In this episode, I geek out with David Goldstein, founder of Hydronic Shell Technologies, about a novel building retrofit technology that wraps old multifamily structures in insulated panels with built-in HVAC systems. Goldstein's approach allows for energy-efficient upgrades without interior disruption, potentially solving a major challenge in building decarbonization.
Text transcript:
David Roberts
Hello, everyone. This is Volts for September 25, 2024, "A new way to retrofit old buildings from the outside." I'm your host, David Roberts. One of the biggest and most difficult problems in building decarbonization is what to do about old multifamily residences — anywhere from four stories to a few dozen — that are poorly insulated, expensive to heat and cool, and uncomfortable to inhabit.
Most retrofits, especially anything that would even approach zero-emissions, are prohibitively expensive for the owners of these buildings, not to mention invasive, especially if, say, heat-pump minisplits must be installed in every residence. But what if you could insulate a building, dramatically reducing its energy demand, and update its HVAC systems, dramatically reducing its emissions... all without messing around inside it at all?
That is what a New York City startup called Hydronic Shell Technologies is doing. It begins with attaching a new facade to the exterior of the building in the form of standardized, insulated facade panels. Think of them like Legos or Tetris pieces — they fit together snugly to create an airtight seal around the building, in the process replacing flimsy old windows with hyper-efficient new ones. Insulated facade panels are not new; they were pioneered in the Netherlands years ago.
What's new is, Hydronic Shell is embedding HVAC components into the panels so that the facade itself becomes the distribution system for central heat pumps connected to individual window units.
It's called Facade-Integrated Mechanical Systems, or FIMS (for those of you who love new acronyms). There's a lot more to say about this clever idea. But, I have David Goldstein, the engineer who developed the technology and founded the company, with me, so I'm going to let him tell it.
With no further ado, David Goldstein, welcome to Volts. Thank you for coming.
David Goldstein
Thank you so much for having me, David.
David Roberts
I have to say, just upfront, reading about this technology really, like, tickled my, whatever you call it, my geek funny bone. Very pleasing. I have no idea if it's going to work as a business strategy, but just conceptually, it's just very satisfying, I have to say. So before we jump into it, let's move back a little bit and talk, just for two or three minutes, about what is the problem that this is attempting to solve. What is the problem that these FIMS are meant to solve? Let's talk just a little bit about what kind of buildings we're talking about and their current state, and sort of like the other retrofit alternatives on the table.
David Goldstein
Yeah. Well, as a fellow geek, I'm excited to have this conversation with you because I'm equally excited by it. So, let's start zoomed way out. And I'm sure you and many of your listeners know this, but buildings are obviously a huge contributor to greenhouse gas emissions. And, you know, something like 40% of global emissions come from buildings. So, we have a huge challenge ahead of us with the number of existing buildings that need to be retrofit. You know, we have all these net-zero targets, net-zero by 2050. But that's going to require a huge amount of these retrofits in a very short period of time.
And so, our focus is on multifamily buildings, especially old multifamily buildings. These tend to be some of the largest emitters just because of their age and their poor condition. So many of them built without any insulation, they're very leaky, and they tend to have these old boiler systems distributing steam or hot water throughout the building. And that's very inefficient as well. So, these buildings have really high emissions. And not only does that make them so important, they're also extremely challenging because they need all this significant work to be done in order to decarbonize them. But people live in them.
And that's really the crux of the challenge. I mean, you explained it well in your intro, but, you know, doing work, doing construction in an empty space is one thing, but when you try to do construction in an occupied space, and not just an occupied space, but someone's home, you know, people's living rooms, people's bedrooms, it becomes a much bigger challenge, especially for multifamily. Like, if you think of single-family homes, for example, someone wants to do a retrofit. When they start with that retrofit, you know, the homeowner is on board. It was their decision to retrofit their home.
But if you're talking about a multifamily building with 100 people in it or 100 families, they're not necessarily all on board. And they don't, you know, have an opportunity to meet the contractors and choose which one they want . To them it's just a random contractor coming into their home to do work. And so this creates a really challenging logistical situation, which is not good for the people who live in the buildings. It's not good for the contractors. The contractors don't like to be working in that kind of situation, and it's definitely not good for the building owners because it makes the work much more expensive, makes it take much longer, and it just makes it a lot riskier.
You end up with a lot more unknowns associated with the project. And so, the whole idea of what we're doing is to kind of eliminate that major challenge, as you said, by doing the work on the exterior.
David Roberts
If I'm the owner of, I don't know, a ten-story multifamily residence, and I'm looking to do like I want to — I take New York City's new regulations to heart and I want to go zero emissions. What's on the table now? Like, what will people do for me now? What is the sort of standardization go to if I'm geared up to do it?
David Goldstein
Well, that's a really good question.
David Roberts
Is there even an answer? I mean, is there a standard?
David Goldstein
Exactly. Exactly. There kind of is no standard to go to, you know. That's something I would say the industry is trying to figure out right now.
David Roberts
Yeah.
David Goldstein
If you talk about old multifamily buildings undergoing deep energy retrofits and decarbonizing, I mean, how many of those projects have actually been done? I don't know the exact number, but, you know, it's a small handful.
David Roberts
And so many left to do, as you say, in such a short period of time. Yeah, this is really one of the thorniest — I mean, you know, people talk about difficult-to-decarbonize sectors. I've always thought that, like, buildings should be first on that list, just because, as you say, it's like a logistical problem and just a mechanical, physical problem and an economic problem, because, like, these are not necessarily wealthy people who own these buildings. They don't have a ton of spare capital lying around. So then let's talk about your alternative then. So there are four basic components to your system, and I kind of want to walk through them all one by one.
But just to list them, there's the central equipment, which is producing the heat or cooling, which I think is most often going to be a heat pump, but theoretically could be anything that creates heat and cooling. Like, what are the alternatives here for the central unit?
David Goldstein
Yeah, I mean, in an ideal scenario, and I would say the vast majority of the time, it will be a heat pump, but it's sort of agnostic to what the source is in terms of the functionality of the system. So, you know, theoretically, and these are just some random examples, but if a building owner has a new boiler that they just installed and they don't want to get rid of it yet, maybe you'll hook the system up to that new boiler, for the time being, until the end of that boiler's life, and then you'll put in a heat pump.
David Roberts
Or a ground source heat pump. Presumably, you could —
David Goldstein
Well, yes. So, a ground source heat pump is definitely an option, and I hope to do a lot of those.
David Roberts
Yeah, or I guess if you're really lucky, there'll be some sort of district heating or centralized network to hook into. And you could do that too, right? Basically, roughly agnostic to the source of the heating and cooling.
David Goldstein
Yeah, exactly. Especially in the dense urban environment where you have a lot of these big multifamily buildings packed together, the idea of doing a district thermal network is extremely attractive.
David Roberts
Yeah, we're extremely into that here on Volts. Okay, well, let me just get to the list real quick. So there's the central equipment, there's the ducts and pipes that lead down or up from the central equipment to these, you call them terminal units, little heating cooling units in the windows, and then there's the facade panels that are covering the ducts and pipes and the terminal units. So that's the four pieces, we're going to go through them one at a time. Central equipment, as you say, could be a heat pump, could be a boiler, could be anything really.
Could be located on the roof of the building, could be located in the basement of the building, or anywhere else. Can it be inside the building, or do you almost always want it outside the building somewhere?
David Goldstein
It certainly can be inside. The example you gave of a geothermal heat pump, in that situation, you probably want that geothermal water coming into the cellar of the building, and then you can have your water-to-water heat pump in the cellar.
David Roberts
Talk a little bit about your decision, like, say, for, I don't know, like a twelve-story building or whatever. You're not just trying to install one giant heat pump to cover all the units, you're doing this zone thing. Talk a little bit about that.
David Goldstein
So, when you look at heat-pump options, there's kind of two ends of the spectrum. You can have unitary heat pumps, which is kind of one extreme where you actually have one little heat pump in every room of the building, or you can go to the other extreme and have one big heat pump serving the entire building. There are pros and cons of each one, but the way we approach it is to kind of find a sweet spot between the two. So, it is a central system, but it doesn't necessarily make sense to have one big central system.
If you think about a building with a large footprint, certainly for at least a significant part, we'll be looking at large buildings. If you were to put one large heat pump, say, in the center of the roof, that becomes a very big, heavy heat pump that requires a lot of structural support to support it. But then you end up with a lot of distribution piping to get all the hot water and chilled water from that heat pump to all ends.
David Roberts
Loud, too, yeah?
David Goldstein
Yeah, exactly. You know, it's more complicated to operate and maintain a very large unit like that. So, the idea is we're not at large commercial size equipment. We're more like light commercial kind of size equipment. It's equipment that's easy. You could fit it in an elevator and lift it up to the top of the building in an elevator. You don't need a huge amount of structural support to support it on the roof. It's not necessarily visible from the street. You don't have this giant thing sitting on the roof that's an eyesore from the street. And again, it just makes the distribution simpler because you're not distributing to all corners.
David Roberts
And quieter, too.
David Goldstein
Yes, and definitely quieter.
David Roberts
Not to obsess over the noise issue here, but I'm going to bring it up repeatedly. It's quieter. So, you have these, like, zones where you'll have a sort of smaller heat pump that serves, I don't know, like how many— I mean, I don't know if there's a rule of thumb, but just like, how many sort of apartments are you gonna hook up to an individual heat pump?
David Goldstein
Yeah, so it's one of those things, you know, one of the challenges with buildings is that every building is unique, and there's kind of no one size fits all. So, it'll really depend a lot on the specific building and the height of the building in particular. But, you know, one of the beautiful things about taking an approach where you not just install heat pumps, but also insulate the building and air seal the building, is you can actually get the heating and cooling loads very low in the space. So, you don't need a large heat pump to heat a large number of apartments.
So, kind of the layouts we're working on right now, just to give you a sense, I would say one heat pump on the roof might serve 14 to 25 apartments. It could be more than that if you're dealing with a taller building, but I would say in that sort of range.
David Roberts
So, for a really big building, you could end up with three, four of these on the roof, theoretically.
David Goldstein
Yeah, exactly.
David Roberts
Okay, another question while we're talking about the central thing. You have these zones, just conceptually, do you need to cover the entire building? Like, you don't get the insulation and the air sealing unless you're completely wrapping the building, right? Like, you couldn't do this in just one zone. You sort of need the complete wrap, do you not?
David Goldstein
Well, to your point about zoning the central equipment, I mean, theoretically, maybe even more than just theoretically. Practically, let's say you have a building with four wings. You know, you have like an X-shaped building with four wings. You could do one wing of the building, insulate that one wing of the building, and put your central equipment on the roof to serve that one wing of the building. You don't necessarily have to do the other wings. I mean, obviously, the intent would be to do the whole building. But if, you know, maybe for financial reasons, the project needed to be phased, it's certainly possible to do an approach like that where you do kind of one portion at a time.
David Roberts
So, you can still get a decent air seal if your facade is sort of running up against the building at one end of it, and not another facade panel. If that makes sense.
David Goldstein
Yeah, it's one of those details, you know, that you have to look at and make sure you do carefully. You have to make sure, wherever that interface is between the retrofitted and the non-retrofitted portion, you probably want to take extra care to make sure it's properly sealed, but it should be doable.
David Roberts
Okay, so a couple of heat pumps up on the roof. Not unfamiliar. So, coming down from those heat pumps to individual window units, and we'll discuss the individual units in a minute, are pipes and ducts. Explain what they're doing and what they're carrying.
David Goldstein
Yes, so the pipes are doing heating and cooling to this space. They're carrying hot water if the system is in heating mode, and they're carrying chilled water if the system is in cooling mode.
David Roberts
Not refrigerants, which is a little bit of a hassle when it comes to normal heat pumps. Right. This is all water.
David Goldstein
Exactly. And that's an important point. You know, refrigerants are fine for some applications, but as you know, there are certainly issues with refrigerants, whether it's environmental issues, safety issues around flammability, things like that. In general, there can be issues when you have refrigerants, especially in larger quantities. And so when you get to bigger buildings, where you have bigger systems with longer distribution lengths, you're not just distributing 20ft from an outdoor to an indoor unit, but it's a hundred-foot-tall building, you have much more distribution. So you're talking about much larger quantities of refrigerant. So, using refrigerant becomes more and more of a problem.
So, especially for larger buildings, water really becomes a much more effective way to move the heat around the building.
David Roberts
Right. So, you have pipes carrying heated and cooled water. And what are the ducts doing?
David Goldstein
So, the ducts are addressing the ventilation needs of the building. It's important to talk about that a bit because we're talking about electrification, decarbonization, and heat pumps. But it turns out, ventilation is actually an extremely important part of the larger puzzle.
David Roberts
Yeah, I should have mentioned that in my intro, actually, especially if you're going to wrap an air sealing around the entire building. We had an episode on passive house standards a few weeks ago and sort of learned about this. Like if you're going to insulate the whole building with an air seal, obviously getting fresh air into it becomes much more important.
David Goldstein
Yep, exactly right. I mean, even with the leaky buildings we have today, these older, often neglected, multifamily buildings already have big indoor air quality problems. This was one of the things that really opened my eyes when I had my first experience working on a project like that in one of those buildings. But it really is, I would say, a huge public health emergency that people are just forced to breathe really poor air quality day and night, and there's nothing they can really do about it. And like you said, as soon as you seal that building, the problem is only going to get much, much worse.
So, really, we can't do this kind of work without addressing the ventilation needs of the building as well. And so, part of the way our system works is that we provide a complete ventilation system. So, that includes ventilation air. So, that's outside air that gets treated by a central ventilation unit. So, it's filtering the air, it's tempering the air, so heating it in the winter, cooling it in the summer, and it's also dehumidifying the air. And we're distributing this fully conditioned air down that distribution within the facade so that it can be supplied to every living room and every bedroom in the building.
David Roberts
So, the same window unit that we're going to talk about in a minute is bringing the heat, bringing the cool, and bringing the fresh air. The same unit is the source of all those things.
David Goldstein
That's right. So, we have that distribution, the ductwork, and the piping running in the facade. The terminal unit is essentially plugging in to that distribution network. So, at the window, you have this terminal unit that plugs into the piping, and it plugs into that ductwork to be able to deliver that heating, cooling, and ventilation into the space.
David Roberts
Yes, this is an area where I feel like the audio nature of this medium is a disadvantage. It's very helpful to look at a picture of this. So, you have these facade panels that you're hanging on, basically hanging on the front of the building. And so, just for listeners' benefits, you can imagine the sort of, there's a facade, and then there's the original facade of the building, and there's a little gap between them, basically. And that gap is where all the ductwork and piping goes. So, I'm guessing you are either buying or making your own extremely narrow piping and ducting.
I mean, what do you have, like, six inches there to work with?
David Goldstein
That's right, six inches. And so, fortunately, the ducting and piping are all very standard components that you can get at any HVAC shop that any contractor is familiar with. Sheet metal ducts, galvanized sheet metal, will have a depth of it being anywhere from four to five inches so that it can fit within that six-inch cavity. And that's standard ductwork in the industry. And then the piping is also quite small. Again, the loads in the building are very low. So that means you don't need a lot of hot water and chilled water for the system.
David Roberts
Yeah, this is worth emphasizing again and again. I just want to say it one more time. Like, if you are insulating the whole outside of the building as part of this process, you're just dramatically reducing the need for both heat and cool. So, you can have smaller equipment.
David Goldstein
Right. On a conceptual level, that's key to making this whole system possible.
David Roberts
Right.
David Goldstein
If you're going to jam a whole HVAC system into a little cavity in the facade of a building, you can't do it unless the loads are very low. So, the two really work together.
David Roberts
All right, so you have this narrow ducting and piping that's coming down behind the facade and hooking up to this terminal unit. So people can think of it sort of like the window in the original apartment gets popped out. You put this facade over the top of it. That's got this newer, better window in it. So, in the little gap between where the old window was and where the new window is, that's where this little terminal unit fits in. And I guess from the resident's perspective, you sort of walk over to your window, look down at the window sill, and there's like a grate, basically. That's what the unit looks like to the resident, basically a grate underneath the window. So, let's talk about these terminal units. Like, what are they doing? What's on them? What do they look like? How do you interact with them?
David Goldstein
Yes. So, the terminal unit is a relatively simple device in terms of what it's doing. There are very few components, actually, in the unit. And in the industry, we call these units "fan coil" units, and the reason we call it that is because that's exactly what's in it. There's a fan, and there's a coil. So, I mentioned that you have hot water and chilled water coming to this unit. So, that hot and chilled water runs through a coil, which is like a finned metal heat exchanger that you see on any AC unit, either an outdoor unit or an indoor unit, very common in the HVAC world.
So, it's that coil, and then you have the fan sitting right next to the coil that's circulating the air over the coil. So, if you're heating the space, you have hot water running through that coil, and then the fan is circulating the air over that coil so that the air will get warmed up by that hot water. And so, the air comes in from the space, runs over that coil, gets heated up, and then gets blown back into the room. So, it's recirculating the air.
David Roberts
And I'm guessing these fans in the terminal units are relatively quiet.
David Goldstein
Yes, exactly. You know, one of the good things about having a unit that has no compressor is that, usually, with HVAC systems, it's the compressor that's creating the noise. So, with a central system, the compressor is up in the central unit.
David Roberts
Right.
David Goldstein
So, in the actual terminal unit in the room, the only moving part is that fan.
David Roberts
Got it.
David Goldstein
And because there's no ductwork, you know, there's no real resistance to the airflow. It's not like you're pushing air through, you know, an elaborate snake of ductwork. There's very little resistance to airflow. So the fan doesn't need a lot of power; it doesn't need to generate a lot of pressure to circulate the air. So, it ends up being a very quiet fan.
David Roberts
And just to clear this up, like, do I have individual controls on my window unit? Like, I can specify the heat level in my unit individually?
David Goldstein
That's right. So, I mentioned two main components in that unit. There's the fan and the coil. But the third component is a control valve. So, that's a valve that opens and closes to either start or stop the flow through the coil. Each room will have its own thermostat. A wireless thermostat will be on the wall. We do wireless so that, you know, again, the idea is to be non-invasive. You don't want to run wires through space. So, a wireless thermostat on the wall will tell two things to that unit: It'll tell the valve to open or close, telling it to, you know, if it needs water or doesn't need water, and it will control the fan speed.
So, you know, the units are sized for the peak load, but most of the time, you're not at peak load. So, to your point about being quiet, if you don't need to run the fan at full speed, you can save a little bit of energy and make the unit even more quiet by slowing the fan down.
David Roberts
Right. So, I'm not messing with the unit itself. The only way I interact with it, basically, is setting my thermometer where I want it.
David Goldstein
That's right.
David Roberts
Is the idea that one of these units in one window of one room is going to heat and cool the entire apartment, or is the idea that each room with a window to the outside is going to have one of these units?
David Goldstein
The latter. So, basically, every room needs at least one of these. Most rooms will need one of them at the window, and it will serve that room. But, you know, if it's a very big room that has multiple windows, you might need two.
David Roberts
Got it. And I'm guessing these window units, I mean, the way you describe them, they sound quite simple. I'm guessing they're relatively cheap. Like, it's not a big problem to have a bunch of them. To have them on every window.
David Goldstein
Yes, all of the parts that are going into this unit are really commodity pieces within the HVAC world. None of them are expensive. So, this is a unit we developed ourselves because what's unique about the unit is really the form factor. It's creating a unit that can sit within that six-inch cavity that's narrow enough to fit in there. Not only that, but once it's sitting in there, the only way you can access that unit is through that top grill that you described. So, you have to kind of arrange all the components in there so that all the maintenance, you know, if you need to replace a valve, if you need to replace a fan, everything is accessible through that top grill.
And even if you need to replace a unit, you have to be able to kind of disconnect the unit from the piping and ductwork, slide the unit out, and drop a new unit in. So, it's a simple unit, but the form factor of it is unique.
David Roberts
And so, it could be replaced with relatively little disruption then. You just sort of, like, unplug the old one and plug a new one in, more or less?
David Goldstein
Yep.
David Roberts
Very cool. One other interesting aspect of this is the space itself. The cavity space between the original facade of the building and the new facade you've hung on. One of the questions that popped up in my head, which you answered in one of your videos, is, I'm thinking "This space between the old facade and the new facade is effectively outside. So, is it not going to get cold in the winter, for instance, and freeze all that water that's going through all those pipes?"
But then, it turns out that this space is conditioned. So, talk a little bit about how you're thinking about that cavity space and what you're using it for. Because it comes in handy in a couple of different ways.
David Goldstein
So, when we put this new facade on the building, this new outer shell, you can basically think of that as the building's new thermal barrier. So, anything that's inside of that shell is essentially indoors. Now, the tricky thing is, when you overclad a building, what you tend to do is you run the risk of trapping moisture between the old facade and the new facade because you're creating this airtight, watertight environment.
David Roberts
And you're moving hot and cold water, too. Seems like an invitation to condensation.
David Goldstein
Exactly. So, that's actually been a big issue with these types of overclad retrofits. You mentioned in your introduction that these kinds of overclads started in the Netherlands, and became more popular in Europe. But, this issue of trapping moisture and condensation becomes more of an issue when you get into colder climates.
David Roberts
Yeah.
David Goldstein
So, if all you do is overclad the building, you could run some real risks there with moisture in that cavity. So, the way we get around that is by actually conditioning that cavity and specifically dehumidifying it. And the way we do it is conveniently, we're delivering dehumidified ventilation there to each apartment through the ducts. So, we already have that distribution right through the ducts that are already sitting in the facade. So, essentially what we do is we say, "Hey, let's just take a little bit of air off that ductwork, and let's supply it directly into the facade, into that cavity."
And so, we're effectively dehumidifying that cavity, and it really only takes a very small amount of air to do that because it's not, you know, the space itself is not a large volume, and it's not like you have moisture loads, like, constantly pushing moisture into that space. So, really, just a small amount of dehumidified ventilation air can keep that space nice and dry.
David Roberts
So, that's warm, dehumidified air basically circulating in that cavity, keeping it dry.
David Goldstein
I would say it's tempered air. It's probably around 60 degrees. I mean, it depends on the season. It depends on how you want to operate your building, but it'll probably be in the 60 to 70 degree range, that's the air that you're circulating.
David Roberts
Talk a little bit about how you're making use of thermal storage, which I found fascinating. Like, the main heating of the indoor spaces is through this forced air through this unit. But then, there's also this supplement. Talk a little bit about that.
David Goldstein
Yes, so, like you said, this is a pretty interesting aspect of what we're doing. So, I just talked about dehumidifying that cavity and kind of tempering it. But we then take it a step further where we can actually heat the cavity. We have hot water running through the facade in the wintertime, and we can put a small heat transfer element using that hot water to actually heat the cavity itself. And so, what that does is it creates this really interesting condition. So, we have this cavity. On one side is this super-insulated new facade. On the other side is this old, uninsulated masonry wall.
So, the heat in that cavity is going to conduct through the uninsulated side, and it's essentially going to warm up that wall.
David Roberts
Right. The masonry is just going to absorb some of the heat.
David Goldstein
Exactly, exactly. And we're not talking about it getting very hot. We're talking about the temperature in that cavity maybe being 80 degrees, 85 degrees, and then that wall maybe is warming up to 75 degrees, which, you know, the typical set point in winter time for a space is around 70 degrees. So we're just talking about getting that wall a few degrees warmer than the air temperature in the space, but that's enough for that heat to essentially radiate from that wall into the space. So, you may be familiar with radiant floor heating. So, this essentially becomes radiant wall heating.
So, it's a very comfortable, very efficient way to heat the space.
David Roberts
Yeah, cause this is a phenomenon. I forget what the name for it is. But, like, even if the air inside is warm, if the surfaces you're near are cold, you're sort of getting radiant — you're like losing heat that way. So, warming the walls is actually not a small thing, comfort-wise.
David Goldstein
Yeah, what you're describing, what it means is that, say I have a traditional heating system in my room. I need it to be 72 degrees to be comfortable, and that might be because my window and my wall are cold. So even though the space is 72, I have those cold surfaces affecting my comfort. If all of a sudden, you heat that wall. So now that wall is not cold, now that wall is actually warm, and you have a super-efficient window, like a triple-pane window that's not really getting cold. And now, because I don't have those cold surfaces, instead of needing 72 degrees to be warm, I can have the room at 70 and feel just as warm, or 68 and feel just as warm.
So, you're able to keep your space temperature lower, but feel the same comfort. But you mentioned thermal storage, and so where it gets really interesting is once you've heated up that wall, that's a massive masonry wall, it has a lot of thermal mass, so you're actually storing the heat in that wall. So, if you think of an example where you want to do demand response, which is, you know, the grid is seeing a peak. You know, it's a really cold winter night. The grid, you know, is experiencing a peak, and the utility wants people to curtail their demand, just as an example.
And, you know, utilities pay people to do this. This becomes very simple for the building. Now, all they have to do is turn the system off, and the heat that's in that wall will just continue radiating into the space and continue heating the space. And again, going back to the super-insulated building, bringing the loads way down. Just that little bit of heat can actually keep the space comfortable for a long time because the loads are so low.
David Roberts
That raises a question that I had about electricity, because you have this super-insulated shell. So, ventilation is super important, and the ventilation is being achieved by an electric heat pump or a fan. What happens if the electricity goes out? Do you not get very sort of clammy, oppressive air pretty quickly once the ventilation stops? Like, what happens in the event of a brownout or a blackout?
David Goldstein
Yeah, well, I mean, that's a very good question. As you said, if everything just turns off, thermally, you'll probably be fine.
David Roberts
Right.
David Goldstein
But your ventilation is going to turn off as well.
David Roberts
Right.
David Goldstein
You know, you can open your window. You always have operable windows as a kind of last resort if the air is really getting stale and you need to do something. But that's where, again, going back to the fact that every building's unique, every project will have different requirements. If that's a concern, then I would say the main way to deal with that is to have backup power, backup generators, whether it's batteries or whatever kind of backup it is.
David Roberts
Yeah, it'd be good to be on a little microgrid or something.
David Goldstein
Yeah, and it depends on how long. If the power's off for a couple of hours, it's probably not a huge issue. But if we're talking about days, then I'd say this one can be concerning.
David Roberts
The one piece we haven't really talked about is the facade itself, the facade panels. I'm guessing that different building owners will want different facades. Like, are you making the facades, or are these like an off-the-shelf product that you can just buy and add your stuff to? Or do you have to make sort of bespoke facade panels?
David Goldstein
So, it's kind of a little bit of both. We are not making our own facades. The idea is, as you said, different people are going to want different things. Whether it's the aesthetic or particular materials or certain levels of efficiency, people are going to have different desires for their individual buildings. And so, our intent is to make the system very flexible, to be able to work with, you know, lots of different facade options. You know, there's no reason you couldn't do it with all different materials, you know, depending on what the owner wants. Of course, you know, you have some limitations.
Like, you can't use super heavy stone. You know, if you're hanging this on the side of an existing structure, you don't want it to be too heavy. You want it to be lightweight. Obviously, you want it to be affordable, but it is generally very flexible. You know, our company philosophy in general is that we're really specializing in developing this innovative HVAC system that kind of unlocks this potential to do these types of retrofits. But that's really where our specialty lies. Our specialty is not as a facade company. My background is as an HVAC engineer.
I'm not an expert in facades, although I'm certainly learning a lot about it through this process. Our strategy is to work with existing facade manufacturers to develop facades that will work for us. There are existing products on the market to do overclads, and essentially those same products will work with our system. There's a little bit of integration work that needs to happen, like maybe some minor modifications to the facade system, some modifications to the way it's anchored, or, you know, things that need to be done to create that cavity. But in general, it is through partnerships with facade manufacturers that will bring this whole system to the market.
David Roberts
The facade itself is not that mechanically complex. It's just kind of like plywood with some material on the outside. Right, I mean, there's not — these don't strike me as, like, a ton of variation possible, other than, like, the look of it aesthetically.
David Goldstein
Yeah, I mean, you know, my initial thought was the same. Although now that, you know, we're getting into the nitty-gritty details of, you know, developing these systems with a few different manufacturers, they actually can be pretty complex. They're not that complicated in the sense that there's no moving parts.
David Roberts
Right.
David Goldstein
It's just an insulated material and a structural material to give it rigidity. And you need some degree of fire-resistant element to it, so it can't spread fire. But the complexity is more around the installation process. It's around the anchoring system. Like, how do you design these anchors to attach to the existing structure? And then how do you design those anchors so that you can easily hang the facade panel to them? And then how do you actually seal between the facade panels?
David Roberts
Yeah, yeah, that's what I was gonna ask. Like, what does it look like? How do you create an airtight seal between these two big chunks that you're, you know, 100 ft up in the air hanging on the side of a building?
David Goldstein
Yeah, so facades, you know, panelized facades are extremely common in new construction. Right. You know, you see a lot of tall buildings, or maybe even not tall buildings going up, where you see people lifting facade panels into place, or even from the interior, putting facade panels on the exterior of the building. So the whole concept of sealing between panels and how that gets done is pretty standard, and it falls into two categories. You have what's called dry seals or wet seals. So a dry seal is where you have some kind of gasket material where the two panels come together and the gaskets form a seal.
And that's good because there's not that much labor involved. It's really just putting the two pieces together. The alternative is a wet seal system, where you put the two panels next to each other, and then you have a wet silicone kind of seal that has to be installed between them. That's a bit more labor-intensive, but a bit simpler. So there's pros and cons to either one, and we can potentially do it either way.
David Roberts
Right. So, if I clad my building in one of these systems with the facade airtight and the ventilation system that you describe, am I going to meet Passive House standards? I mean, it sounds like that's basically what Passive House is, right? It's like an airtight seal and good ventilation. Are you going to meet that standard?
David Goldstein
Yeah, so I would say potentially. And the only reason I don't say "yes, definitely" is because I'm not 100% sure, but I believe, essentially, to be a Passive House, ultimately, the metric is, what is your energy use? So they have what's called the EUI, the energy use intensity. And to meet the Passive House standard, you basically have to meet a certain energy use intensity from your heating and cooling system. Now, there's all sorts of ways to do that. You know, all the principles of Passive House with eliminating thermal bridges and high-performance windows and all these things. But ultimately, I think the question of, "Is your building achieving passive house or not?"
I think it comes down to whether or not you're hitting that energy metric, and so the only reason I say "maybe" for us and not "definitely" is because I wouldn't want to set a somewhat arbitrary metric as, you know, a necessity. You know, let's just pick a random number. Let's say the passive house heating EUI, let's say it's three kBtu/ft2 per year. I don't know if that's exactly what it is, but something like that. If we end up designing a project and, you know, choosing the materials that make sense for us based on, you know, budget constraints and, you know, whatever, and we end up with a 3.3 EUI for heating, I'd say that's good enough.
We don't necessarily need to, you know, hold ourselves to the Passive House as a requirement.
David Roberts
So, let's talk about what buildings can do this then. What are the restrictions? Like, one thing that occurred to me, and I saw you say this in a video too, it seems obvious in retrospect. Obviously, you can't do one of these big all-glass buildings, right? Because you got these panels that have stuff in them, so they have to be opaque, right? So, at the very least, you can't do all glass. Are there other sort of restrictions on the type of building, the type of building facade this works on?
David Goldstein
I'd answer this in two ways. You know, if we kind of step back and look at our longer-term vision, we imagine just this general concept of integrating the HVAC into the facade of a building. We see ways that that can be done for lots of different building types with lots of different physical characteristics. Even an all-glass building, if the building owner is okay with blocking off a portion of that glass in order to have that duct and pipe distribution that's kind of blocking it, then it's certainly doable. And, for an all-glass building that wants to be energy efficient, maybe that's a smart thing to do.
Maybe you don't need to be an all-glass building anymore. So, you know, that's one example. But even looking at other building types, like office buildings, for example, there's no reason that this kind of approach couldn't work for an office building. But it's just different.
David Roberts
Yes, why are you focusing on multifamily? There are some reasons you're not starting with offices or commercial buildings.
David Goldstein
Right, so multifamily is really ideal for, I guess, a couple of reasons. One is that they tend not to have deep floor plates. So, we're talking about conditioning a building essentially from the exterior, from the perimeter of the building. So, if you have a space that's, you know, 50ft deep, then that's a lot harder to do. But with multifamily buildings, you typically don't have deep spaces like that. You're typically not allowed to by code or every space has to be within a certain distance of an operable window for light and air. So, from that perspective, multifamily works really well.
The other perspective is that multifamily buildings tend to have small internal loads. So, you know, if you look at the cooling load of a building, you have the envelope, where you have your exterior loads, like the sun coming in and, you know, it's really hot outside and that's conducting through the wall. So you have your perimeter loads of the building and when you super-insulate a building, you can bring those loads way down, but then you still have your internal loads in the space. Things like lighting or people or, you know, your computer and your TV that's plugged in.
David Roberts
These are not commercial machines in the case of a multifamily building.
David Goldstein
Exactly.
David Roberts
Just ordinary appliances.
David Goldstein
Exactly. So, your internal gains, heat gains in a multifamily building are relatively low. Once you super-insulate the facade, your overall loads can be very, very low. But, to your point, with an office building, you can have tons of computers and commercial density of lighting and lots of people packed into a space. So, your internal gains are still much higher. Even though you're super-insulating the facade, you still have all these internal gains. So, your loads in general are higher. And then, the other thing is you need a lot more ventilation air for a space like that.
If you have 30 people in a section of an office, they need a lot more ventilation there than just a living room does. So, when we're talking about squeezing ducts into a narrow facade cavity, it's a lot harder to do that if you need much higher volumes of ventilation there. There are approaches you can take where, and we're not doing this now, but we foresee in the future where you could do this exterior approach essentially just to handle the perimeter loads of an office building, but then still keep your existing interior systems to handle those internal gains. There are ways to make it work. But, multifamily really is the most straightforward for taking this kind of approach.
David Roberts
I'm just curious, from a resident's perspective, if a building owner says, "Yeah, I want to do this," does the resident ever need to move out? Like, you do have to pop the window out. Can you do that from the outside? Can you do everything from the outside? Can the residents just chill inside and not worry about this?
David Goldstein
I would say yes, the residents can chill inside, but not all of the work is happening from the exterior. And that's to your point, it's really the window. So, the way this will happen is the new facade panel will get installed on the exterior and all the HVAC distribution installed on the exterior. But then the window, the existing window needs to be removed from the interior. So, after all that stuff gets installed on the exterior, a contractor will have to come in, remove the existing window.
David Roberts
Oh, so the whole outer facade is put in place and then the original windows are removed?
David Goldstein
Correct. So, the contractor removes the original window, and then you end up with this kind of unfinished window opening that they have to do some finishing work to close it up, to make that whole new window sill look nice and everything. So, the residents definitely don't have to move out. And even when you do retrofits, even when a resident doesn't have to move out, sometimes it's still very invasive, just to have the contractor doing work throughout the apartment. Maybe you have to move furniture around. Maybe you have a big bookshelf here, but the contractor needs to run a pipe across there.
So, you have to move your bookshelf out of the way, and it can still be pretty invasive even if you're not moving out. But with our approach, fortunately, the only access that's needed is at the window, so you don't have to move any furniture around. It's not really a major disruption. And the idea is that it's a small enough amount of work that it could be done in less than a day. So, for the resident, you're going to have one day where a contractor is going to come in, do some work at the window, and then be done.
David Roberts
Sort of the big, obvious question we haven't addressed yet is cost. Just when I think about a big building, an entirely new facade full of HVAC equipment for a big building, that's just a lot of material. It's just a lot of stuff. So, this sounds, on its surface, expensive. So, try to give us some sense of how this fits into the retrofit landscape. What's the pitch to a building owner?
David Goldstein
The two biggest barriers to electrification, I mentioned one, are the invasive nature of the work, but number two is definitely the cost. You can't have a discussion about technology or decarbonization or anything without talking about cost, because ultimately, that's going to be the decider for whether or not these projects actually happen. Now, to your point, putting a whole new facade on the building and putting a whole new HVAC system with distribution is obviously not cheap. But the way we look at it, what we think is the right way to look at it, is to not just focus on the installation cost, but it's about the work being cost-effective, which really has two sides to the equation. There's the installation cost, but then there's the operating cost after you do the installation.
David Roberts
Classic decarbonization story: Big upfront investment, big savings over the long term.
David Goldstein
Exactly. And in this case, it's not just about energy savings. So, obviously, if you super-insulate the building, install this really efficient HVAC system, you will have significant energy savings, which is important. If you just install heat pumps in a building, you probably don't have much energy savings because electricity is generally more expensive than gas. But when you super-insulate the building and bring the loads way down, now, you will have significant energy savings, even though you're switching to electricity. But it goes actually well beyond just your energy savings because you're actually going to see a lot of maintenance savings as well.
And the biggest component of that is actually the facade. So when you talk about these older masonry, multifamily buildings, they actually spend a lot of money inspecting and repairing those masonry facades.
David Roberts
Oh, yeah, right. Interesting. And this will protect that from the weather, I guess. Obviously.
David Goldstein
Yeah, exactly. So, your masonry is essentially indoors now. You never have to look at it again. And you have this new, very low-maintenance, very durable facade material on the exterior of your building. So, you're saving a lot of money on your facade maintenance.
David Roberts
And the HVAC is relatively low maintenance, too. I mean, compared to, I'm guessing, like an old boiler and radiator system.
David Goldstein
Exactly. Yeah. I mean, if you think of an old, big boiler system with steam piping all over the building and steam traps leaking, and just people complaining about too much heat, lack of heat, and someone needs to go and just —
David Roberts
Opening their windows with their radiators on. Classic New York picture.
David Goldstein
Exactly. So, the point here is that you have this upfront cost, which is substantial. You also have the cost savings, operating cost savings, which is substantial. And so, the way to really make it work, from our perspective, is to have financing.
David Roberts
This is, I swear, I have this same exact conversation about every technology. It all comes down to the financing.
David Goldstein
Exactly. Because if you can finance it so that the owner doesn't actually have to pay the money upfront, then that installation cost doesn't become an issue. When the cost savings — if you have significant cost savings, you can use those cost savings to pay the loan payment. Again, very classic example, whether it's with solar or whatever, this is very common. It's just that with buildings, with deep energy retrofits of buildings, it's always been very hard to get that equation to actually work.
David Roberts
Right. Well, this is the inevitable next step in this conversation, which is: Is your technology comfortable enough, familiar enough to banks that they will finance it?
David Goldstein
Right. So, that's a big question. Just to back up for a moment in terms of where we are with our technology development, we haven't installed the system yet. We have our first pilot project on a building in Syracuse that will start construction in the second half of next year. So, the question of, "Are banks familiar, comfortable with it?" No one's familiar and comfortable with it yet.
David Roberts
Not even you.
David Goldstein
Exactly. That's part of the challenge of being innovative and trying something new, especially in the construction industry, which is a very risk-averse kind of industry. But to be honest, we're thrilled just to have this pilot project lined up because that is a huge — that's the biggest challenge in itself.
David Roberts
You're going to need a few people to step up and sort of make the big initial investments, some initial. Just to get a first-of-a-kind thing that people can look at.
David Goldstein
Right. It's unlikely to be just your standard bank loan doing it for these early projects. It's going to be some kind of subsidized loan program, whether it's something federally subsidized, like from the IRA.
David Roberts
Yeah, are there IRA...? I mean, I'm not sure exactly how or where you would classify this exactly, but, like, is there money in the IRA somewhere for this kind of thing?
David Goldstein
There is. It's complicated, and I'm not an expert on all the details. You know, the IRA and where we can kind of take advantage of it. But there definitely is money for decarbonizing buildings. And because we're focused on old multifamily buildings, a lot of those buildings are affordable housing.
David Roberts
Yeah, I was going to say there's a real environmental justice angle here that we haven't even really touched on yet. But another good reason to start with multifamily buildings rather than offices is that, like, there's a lot of very uncomfortable, low-income people living in these buildings.
David Goldstein
Exactly. And, you know, like you said, environmental justice is going back to the public health issue and all of that. So, that is, I think, where the opportunity is right now. And that's where, like you said, the need is most urgent right now.
David Roberts
You mentioned this in passing earlier, but I think it's a really intriguing piece of all this, which is that a lot of these buildings, like just take New York City for an example, are on grids that are quite congested and overburdened. And so, you dramatically reducing total load and also spikes — right, like evening out those spikes over time — is a great help to the grid in these places. So, I just wonder, have you talked to utilities and is there any prospect of utilities helping a little bit with the financing?
David Goldstein
There's definitely a prospect of it. And like you said, it's definitely in their interest. You know, I don't have anything specific at the moment where we have specific support from utilities on any specific projects, but it's definitely for the reasons you said. It's in alignment with their goals of controlling the grid, not overloading the grid. And back to another earlier point about district thermal systems. That's a really interesting area for utilities as well, to operate these district thermal networks. And in a sense, what we're doing really unlocks a lot of potential there because I think with multifamily buildings, the biggest challenge with district thermal networks is you can bring that thermal energy to the building, but then how do you distribute it to each apartment?
And so, that's kind of the piece that we help with. We've had discussions, nothing concrete, but we expect that there's going to be a lot of interest from utilities from that perspective as well.
David Roberts
And especially in cold weather climates, because, of course, one of the big vexing problems with electrification is electrifying heat. In cold weather climates, all things being equal, it's just an enormous new load on grids that don't necessarily have a way to meet it. So, dramatically reducing your energy demand while you're electrifying is so crucial in those climates.
David Goldstein
Yep, exactly. It's like a double whammy in cold climates because you have a higher heating load just because it's so cold out, but also the heat pumps operate less efficiently and have less capacity. So, it's like an exponential kind of challenge that the colder it gets, it just gets much, much harder to electrify.
David Roberts
So, a couple of final questions. One is just sort of like, what do you envision for your company? You're trying to show that this whole thing can work. Like, do you envision being the company that a building owner calls and you go do this, or are you going to license this to construction companies that make facades? Or what's the sort of business model you envision?
David Goldstein
Yeah, it could potentially evolve in different ways. But going back to an earlier point we were discussing, we really see our expertise, the real value we bring, is in this kind of HVAC technology and developing this new kind of HVAC approach. We don't necessarily feel a need to be handling the entire project ourselves. I mean, me personally, like we said in the beginning, I'm a huge nerd. I'm a huge geek. I'd be totally happy just sitting there working on the technology, making the technology better and better, while other people worry about managing construction projects and —
David Roberts
Talking to utilities.
David Goldstein
Right, right, exactly. So right now, our model is that we're going to work with partners who will actually implement these retrofits. So right now, we have a great partner called Cycle Retrotech. They are a retrofit solution provider, basically doing deep energy retrofits. And they have experience with overclads. And so they're essentially going to manage these projects.
David Roberts
They must be geeked about this, right? I mean, this is such a perfect complement to their product, right?
David Goldstein
Yeah.
David Roberts
So, it's just like, it makes so much sense.
David Goldstein
Yeah, I'm really happy with that model, with that approach. They'll manage the project. So, the idea is that these will be kind of turnkey design-build projects. You know, these can't be complex construction projects where the owner has to manage all different consultants and then send these projects out to bid, and who knows how the bids are going to come back. Like, these need to be design-build turnkey projects where someone like Cycle Retrotech is going to go to the building owner and say, "I'm going to retrofit your building for this price."
And then they bring the whole team, they bring the whole package. You know, we talked about financing. They'll bring the financing, make it as simple as possible for the building owner. And, you know, if we just have our tiny role of just providing these certain HVAC components, these terminal units, and maybe having a licensing fee that goes along with it, then that works for us.
David Roberts
You just want to do the engineering. I completely sympathize with that. You also mentioned, actually in passing, in some of your materials that you also think that this system would be preferable for new buildings, which I found quite interesting. Like, the advantages for retrofits are obvious to me. But you think even in a brand new building, integrating the HVAC into the building facade is the way to go, even for new build?
David Goldstein
Yeah, I do. I think it's almost just as interesting and just as exciting to think about what it could mean for new construction. You know, we talk about the urgency of decarbonization of our existing buildings, but we also have an urgent problem with housing and affordable housing. And we need to build a lot more housing in this country and around the world, actually. We need to build a lot more housing. We need it to be affordable. We need it to be efficient and healthy and all these things. So, if you think about building a new building, a new multifamily building, and you think about the HVAC work that happens in that building, you think about the contractor in there installing ductwork for the exhaust systems and piping, whatever kind of heating and cooling system it is, and all this work that happens in the building, which is pretty labor-intensive.
And now, think instead, that the whole structure gets built, the mechanical contractor is not in there doing anything, but instead, all of the ductwork and piping is all prefabricated onto the facade panel. And then you literally just take that prefabricated panel — and these can be big panels, you know, these can be like, 30-foot-long panels, you know, serving a whole apartment — you just take that panel, mount it to the side of the building, and then the work from the inside is just kind of connecting the ducts and the pipes between the panels.
David Roberts
You wouldn't even necessarily need, you know, like plumbers per se, like skilled labor. It sounds like something that, like, anybody could do, basically like stacking Legos. More or less.
David Goldstein
Yeah, so for the HVAC, yes. You know, of course, you still have the sanitary piping, all the plumbing, which probably won't be part of our system. But from the HVAC side of things, yeah, all of that, the work is essentially moving into a factory, which is great for workers. I mean, you know, if I'm a worker, I'd much rather be in a conditioned factory on a stable floor working, rather than on a construction site. So, I think it's better for workers, but it also makes it more efficient. And at the end of the day, again, it all comes down to cost.
We need to build a lot of housing. We need it to be affordable, and this can really reduce the cost.
David Roberts
This is like a custom-built segue to my final question, then, which was about what I like to ask anybody who's got a new technology they're working on, which is: How do you see costs coming down over the long term? What are the sort of channels through which you're going to reduce costs? Because in a sense, a lot of the... just mechanically, there's not a lot that's super complicated here. These are not like, these are not. I mean, that's sort of one of the benefits of the whole thing. These are pretty simple pieces you're assembling here.
So, it's not like small fans are going to dramatically reduce in price over the course of December. So, where do you see opportunities to reduce costs for the whole thing?
David Goldstein
That's a great question.
David Roberts
And what might help, actually, what might help policy-wise, if I can tack that on, too.
David Goldstein
Yeah, the biggest opportunity to reduce cost: So, like you said, the materials themselves, they are what they are, but really, the biggest opportunity is in the labor cost. So, making the installation process more efficient. The more that we can automate. So, you know, let's think about what one of these installations will look like. You essentially scan the exterior of an existing building. You can automate much of that. You take that digital information and send it to the facade manufacturer, who can now fabricate their panels to perfectly match the existing building's physical conditions.
And again, much of that can be automated. Then, you have an anchoring system that we need to make as simple to install as possible. Installing these anchors on the building and then, you know, having your lift or crane or whatever, that's bringing the panels onto the building, we can make that process very efficient. And taking a lot of labor out of the equation. And taking the labor, not just taking it out, but moving it to the factory where it's more efficient.
David Roberts
Yes, as all Volts listeners know, anything you can do that's modular, replicable, and doable in a factory is going to lend itself to a declining cost curve.
David Goldstein
Yeah, exactly. So, if you think about it, if you're doing retrofit work in the apartment, there's no way to take that to the factory. But when you're doing it as part of an exterior panel, now you can take it to the factory and then just bring that panel and slap it on the side of the building. One of the biggest chunks is just improving the processes so that we can make the labor component as efficient as possible. And then the other piece is just economies of scale. You know, when we're doing one building here, one building there, then the cost of those facade panels is going to be a lot more.
And if we're doing 100 buildings, 1000 buildings, so I think economies of scale are the other area where we'll get cost savings, which, again, is something you get with a modular, offsite kind of approach that you don't necessarily get with traditional construction. So, I think those are the two main things. You asked about policy. To me, the hardest part of reducing that cost is getting to that economy of scale, because if it's —
David Roberts
Another familiar story.
David Goldstein
If it's expensive now, then how are you going to get the volumes up to where you can reduce the cost? To me, that's where policy can come in to help support the earlier projects, help support manufacturers to scale up their capacity so that we can actually get to those economies of scale, because I think ultimately, organically, we could potentially slowly get to economies of scale.
But we don't have the luxury of time. We need this to happen today.
David Roberts
In New York City, that's where you're sort of —
David Goldstein
Yep, we're based in Queens, New York.
David Roberts
New York, in particular, has laws and regulations about rapid decarbonization of large buildings. Are there New York state subsidies in particular available or assistance available in New York?
David Goldstein
So, in New York State, we have NYSERDA, the New York State Energy Research and Development Authority, I think something like that. So NYSERDA, you know, that state agency, they're providing a lot of support to kind of get this market going. And we've gotten significant support from them, and they're actually helping to support the pilot project that we're planning in Syracuse. So they, I think they recognize the need and they are trying to help support that market and get that market going. You know, we have laws in New York City, essentially requiring buildings to decarbonize.
David Roberts
They're very aggressive.
David Goldstein
Right. But the way those laws work is essentially, buildings get fined, you know, if they exceed emissions limits. But unfortunately, you know, right now and for the foreseeable future, as much as building owners don't like paying fines, paying the fine is probably easier and cheaper than doing the retrofit. So, you know, a lot of them will probably just be upset and pay the fine, but it won't achieve the desired goal. So certainly, fines like that are not enough to push the market where it needs to go.
David Roberts
Just occurs to me, this is a very random question, but I forgot to ask it earlier. It occurs to me that if you have a building that is newly clad on the outside with a network of pipes carrying water, is that fire prevention? Like, are you, if you thought about that angle at all. Like, is there a fire angle to this?
David Goldstein
Well, I like the way you think. I mean, it certainly could be, you know, fire is a big thing, actually. You know, that's actually one of the big kind of issues we have to deal with is, you know, how do we ensure that this is going to be safe from a fire code perspective? And I think that's a really cool idea. How can we kind of leverage that water in there to help with the fire safety? I hope you don't mind if I use that.
David Roberts
No, please. I'd love to have some small, geeky contribution to this whole thing. Well, David, this has been absolutely fascinating. Such a geeky pleasure. This is real fun work you're doing. I hope it takes off. I mean, it seems like something like this — this is how I always feel when I hear about a cool new tech idea — something like this seems inevitable to me on some time scale. Just like working from the outside rather than having to schlep around inside is such a big thing. Somebody's gonna make it work. Thank you so much for your work and for coming on today.
David Goldstein
Yeah, thank you so much. Really enjoyed the conversation.
David Roberts
Thank you for listening to Volts. It takes a village to make this podcast work. Shout out, especially to my super producer, Kyle McDonald, who makes my guests and I sound smart every week. And it is all supported entirely by listeners like you. So, if you value conversations like this, please consider joining our community of paid subscribers at volts.wtf. Or, leaving a nice review, or telling a friend about Volts, or all three. Thanks so much, and I'll see you next time.
A new way to retrofit old buildings ... from the outside