Beverly Craig of the Massachusetts Clean Energy Center discusses what passive house building principles entail, the benefits they generate for building occupants and the grid, and what it would take to persuade more US builders and policymakers to adopt them.
Having build an almost-passive-house in Vermont in 2012, it's interesting to see the way this discussion is framed. My wife was really into the energy efficiency as an end in itself, and perhaps rightly so. I have to admit that my motivation was more selfish—I have lived in a lot of old houses in cold climates, and they're just so uncomfortable in the winter. It's not even that they're too cold—it's that the only stable temperature you can have in such a house is whatever temperature it is outside. Any other temperature is going to fluctuate.
So in our apartment in Chicago, we had forced air heat with a gas burner, and this was a very effective heater, but the experience was that it would be very cold, and then the heat would come on, and then after a few minutes it would be very hot, and then the cycle would repeat. So you couldn't pick an outfit to wear that you'd be comfortable in.
In our almost-passive-house, I can walk around in bare feet in the winter, and the thermostat can be set for whatever style of clothing we want, whether that's a T-shirt or a sweater. When we've had issues with heat pumps (which we have, unfortunately), and couldn't get an emergency visit to get it serviced, we were able to heat the house with a small space heater. When we had to leave for a couple of weeks during this period (!), we used the space heater to get the house a little too warm before we left, and then just turned them off (we didn't want to leave them running unattended). When we got back two weeks later, the house was still above sixty degrees.
Our current heat pump seems to be quite a bit more reliable, fortunately, but this was a really interesting demonstration of the difference between a truly energy-efficient house and a normal house. In a normal code-compliant house, the only way we could have left the house with the heat off in the middle of winter would have been to drain the plumbing and just let it sink to ambient, which would have happened in probably less than a day.
The downside of this type of construction is that it's hard to say whether we're going to be able to get our money back when we sell it (which we are currently doing). Obviously we would pay extra for a house like this, but until you've lived in one you don't really know what it's like, and so there's a tendency to think of the benefit in terms of dollars and cents. With fossil fuels subsidized to the degree they are, unfortunately I don't think that's sufficient justification.
The reason I mention this is that personally I think if we want to see more construction like this, we really should start talking about it as a luxury that people might enjoy, rather than as a money-saving measure or a carbon-neutrality measure. Otherwise it just feels like a sort of hair shirt exercise, and then people don't see the point of it and don't support efforts to, for example, improve the building codes.
By the way, as a counterpoint to that, if we had it to do over again now, we would probably have gone with a company that has a factory floor where they can manufacture the building materials, because this would have made the dollars and cents work out better. This is pretty common in Europe. The only company I know of in the U.S. who does this is Bensonwood, although I'm sure there are others. You all might enjoy a visit to their factory next time you're in the area. :)
David - Thanks for this excellent episode to introduce your audience to PH. You may not remember it (or have realized it) when we had breakfast together in New Haven, but the place you stayed in for the Yale event, Hotel Marcel, is the first Passive House (PHI) certified hotel in the United States. (in addition to being 100% electric) It is super quiet, air quality is awesome and energy costs are only a third of what they would otherwise be. How did you like it?
Not David, but Andrea and I are Passive House enthusiasts too, so we've made a point of staying there on the way through. It's weird but fun. Honestly the Passive House aspect of it isn't at all obvious unless you're looking for it. Mostly what's interesting there is the design. I guess the fact that the Passive House-ness of it disappears is probably not a bad thing. :)
But that was before the biggest carbon emissions year ever, and the warmest year ever.
Net-zero is so inadequate. 1980 was the last time net-zero was a good idea. Today it's suicide.
If the GHG level stays where it is, the planet's habitability collapses quickly, starting with ocean-acidity driven collapse. Unless you can breath H2S it's time to stop screwing around with net zero buildings.
Only thing that matters now is when we get modular nuclear reactors manufactured.
They need to be dry so there is no fallout clouds to worry about, or containment buildings to delay.
They should be small enough to ship by land transport to repower existing coal and gas facilities. (Which is quite easy with 650C dry reactors of several designs.)
Where are the progressives for progress?
Will we destroy Earth because we are worried about the unintended consequences of saving it?
Oregon has an alternative "Reach" code that accepts Passive Haus standards as an option to the state energy code. Formerly you would have had to do both Passiv Haus design and review AND state energy code design and review, so a lot of redundant effort.
I'd also like to note that I believe one root of the Passiv Haus standard goes back to the 1977 Saskatchewan Conservation House demonstration project, which pioneered radical (for the time) ideas like airtight construction and heat recovery ventilation for a very cold Canadian climate. Despite some issues with innovative technologies, the overall success of that project inspired many others, for example, the staff at the National Center for Appropriate Technology in Butte developed and sold stock plans for what they termed "superinsulated" houses. It also pushed our Oregon solar community to become more rigorous about airtight construction and fresh air ventilation to improve performance of passive solar houses (topics that didn't get a mention at our "Solar '79 Northwest" conference). A lot of earlier thought and research went into our modern standards.
This was such an amazing episode, thank you! I'd love to hear more about updating current housing to passive housing standards: how it works, some experiences with it, if it can be done incrementally, how to order it.
Your "how to electrify your house" pod started with fixing your insulation. This is the necessary prerequisite that almost all houses are missing. There is so much territory here.
The comment about pre-fab also makes sense to run with, how does that work? Why doesn't the US allow it?
I really wish we talked more about this kind of thing in warm climates rather than cold climates. Everyone gets excited about keeping heat in during the winter, or applying heat pumps to more efficiently warm a home. But in many climates (and for many people), keeping cool in the summer is more important than keeping warm in the winter. For example for me in Indianapolis, we regularly get 95F+ and humid days in the summer but winters don't generally get crazy cold for more than a few days at a stretch. The same issue applies more broadly as people keep moving to the sun belt.
"We" have been talking about cooling load reduction in warm or hot or humid or all climates for 40 years. Smart summer-peaking utilities and PUCs and NREL and state energy offices, all.
Minimum AC efficiencies have been regulated up and up for 30+ years by the feds. Minimum standard windows reject solar gain to a much greater degree than back then.
Some of my earliest jobs were working for subs to the Cal PUC to develop and evaluate/model the value of efficiency measures. Many of the best values to the systems and the consumers were cooling load reductions and cooling system efficiency improvements because all CA utilities have been summer peaking. The utilities offered, and I assume still offer, substantial incentives for both new construction and retrofits. One reason American electric peak demand remained level for many years was probably just end-of-life replacement of cooling systems and windows, and some folks who have realized they should seal and super-insulate the cooling air ducts in their 130F attic.
Probably the reason this is not discussed as much right now is that GHG/kWh during cooling periods is dropping wherever solar is being added to the grid, which may even include Indiana, while there is a lot of heavy lifting to reduce the GHG of heating.
The discussion was mostly about multi family homes in a cold climate, where PassivHaus makes the most sense, particularly considering the grid benefits.
However, they aren’t a magic bullet for all dwellings in all climates (and to be clear nobody on the pod was claiming they are). I’d doubt going full PassivHaus makes economic sense compared to a reasonably well-insulated conventional new build single family home with efficient modern heat pump HVAC in Southern California, for instance. This would be even more the case if California got serious about regulatory reform to make it easier to put rooftop solar in.
I am remembering your 2012 Tedx talk at Evergreen College:
"But we now know, to a fair degree of certainty, that if we continue what we are now doing we will face unthinkable catastrophe." Have this analysis changed?
I have to ask, David: do you now still think we can avoid unthinkable catastrophe? And if not, what purpose this diversion into housing energy efficiency? Surely we face unthinkable realities that cannot be mitigated by efficiencies or new technologies. What is your position?
Has any thought been given to exploring the role of Passive House with onsite generation and DC appliances, in conjunction with city block scale DC microgrids, might play in the energy transition as well as this topologies impact on national security.
As far as needing gas for DHW in multifamily (MF). First, here in the very cold Roaring Fork Valley, SanCO2 DHW heat pumps have been installed for MF and are working fine. There in Seattle, the Ecotope firm has integrated other CO2 cycle HPs for DHW with storage and demand response.
Beverly mentioned how LEED-rated buildings, presumably MF, had actual energy use all over the map. I'm a recovering LEED "Accredited Professional." The underlying standard, the ASHRAE Performance Rating Method, used energy $/yr instead of Btus or GHG emissions. Analysts could trade off better lighting, etc., for a less-than-stellar thermal envelope. And it used defaults for envelope section heat loss/gain, which in some cases required the analyst to over-estimate the thermal performance of steel stud walls with lots of corners and such. Also it compared energy cost of the proposed design to a convoluted "baseline." It was trying to not crimp the style of "creative" architects, who like all kinds of corners and overhangs and whatnot even in "affordable" housing. As I understand it, the PH std requires the design to just use less than xy Btu/sf-yr, depending on climate. Where sf is the floor area, so simple design is rewarded. From what I can see around here, once architects accept that, they still figure out how to add articulation and interest in other ways.
Really important discussion. In the middle of a housing shortage and affordability crisis and biodiversity crisis how do you, on top of everything else, ask developers to also embrace new restrictions on how they execute these urgent projects? And then there will be the really heavy lifting of upgrading existing building stock to be low emission. It is hard to imagine that simple GHG emission regulations are going to fix this, even given another 25 years. There need to be some carrots in the form of cost savings or livability and/or serious financial supports, even for the many people who really do care about climate change.
Passive House, or close to it, should be standard building code at least for multifamily. Less than 5% extra to build and the energy savings are forever. Here in NYC where the city is looking to reduce emissions and Department of Buildings has no problem imposing costs on owners in so many ways, it's almost criminal to allow inefficient buildings to be built.
Thank you so much for sharing Ted. We’re looking at building one at home as my office space/have remote workers come stay. As well as I work on a climate solutions recommender that aims to respond to any context or objective. So buildings clearly feature as a main focus area (42% of emissions across the board). At the macro level passive houses make a lot of sense. But at the micro level (consumer) cost is always the challenge. I can’t find low emissions cement at the retail level. The bits and pieces of assembly makes passive a challenging project. Availability and cost remain the consumer barriers. Energy codes will be the kicker I guess..
In response to some of the comments about how PH would fare in different climates (mild, hot, etc.), the PHI standard is formulated as an "energy budget" with specific allocations in kWh per sq ft of floor area for heating, cooling and overall consumption. This means that in milder climates, you would need less insulation than in colder ones, since it will be easier to stay within the building's energy budget. I'm less familiar with PHIUS, but I believe that the principles are similar.
In hot climates, having a well-insulated airtight building enclosure will help reduce cooling loads. Think of how a thermos can keep your soup hot or you iced coffee cold: it helps maintain the temperature difference between inside and outside regardless of whether you're keeping heat in or out.
Thanks for covering this subject! Please revisit it as more information (ie, building PH in hot, humid climates) comes along for both new construction and retrofitting.
Before Texas’ shocking no-power winter a few years ago and even more so since, my pie-in-the sky wish has been to set myself up so that if my area experiences that level of breakdown, at least I won’t freeze to death or die of heat stroke (I’m in the Deep South and hurricanes are a yearly concern) in my own damn house. Years ago I saw a video on YT of a couple in a cold climate who had a mean temperature in their huge house of 60/65 F with no active heating/cooling necessary. Basically, their PH combined with heat from appliances, light bulbs, and body heat was enough. So that’s been my dream for normal use much less when sources of power aren’t functioning or available during an extended crisis.
I’m open to new construction and retrofit, but there’s no info to even say if I’d get the same benefits as experienced in northern climates, and seemingly no experienced architects or contractors in the region.
This pod finally got me to $ubcribe after listening in for a year.
Having build an almost-passive-house in Vermont in 2012, it's interesting to see the way this discussion is framed. My wife was really into the energy efficiency as an end in itself, and perhaps rightly so. I have to admit that my motivation was more selfish—I have lived in a lot of old houses in cold climates, and they're just so uncomfortable in the winter. It's not even that they're too cold—it's that the only stable temperature you can have in such a house is whatever temperature it is outside. Any other temperature is going to fluctuate.
So in our apartment in Chicago, we had forced air heat with a gas burner, and this was a very effective heater, but the experience was that it would be very cold, and then the heat would come on, and then after a few minutes it would be very hot, and then the cycle would repeat. So you couldn't pick an outfit to wear that you'd be comfortable in.
In our almost-passive-house, I can walk around in bare feet in the winter, and the thermostat can be set for whatever style of clothing we want, whether that's a T-shirt or a sweater. When we've had issues with heat pumps (which we have, unfortunately), and couldn't get an emergency visit to get it serviced, we were able to heat the house with a small space heater. When we had to leave for a couple of weeks during this period (!), we used the space heater to get the house a little too warm before we left, and then just turned them off (we didn't want to leave them running unattended). When we got back two weeks later, the house was still above sixty degrees.
Our current heat pump seems to be quite a bit more reliable, fortunately, but this was a really interesting demonstration of the difference between a truly energy-efficient house and a normal house. In a normal code-compliant house, the only way we could have left the house with the heat off in the middle of winter would have been to drain the plumbing and just let it sink to ambient, which would have happened in probably less than a day.
The downside of this type of construction is that it's hard to say whether we're going to be able to get our money back when we sell it (which we are currently doing). Obviously we would pay extra for a house like this, but until you've lived in one you don't really know what it's like, and so there's a tendency to think of the benefit in terms of dollars and cents. With fossil fuels subsidized to the degree they are, unfortunately I don't think that's sufficient justification.
The reason I mention this is that personally I think if we want to see more construction like this, we really should start talking about it as a luxury that people might enjoy, rather than as a money-saving measure or a carbon-neutrality measure. Otherwise it just feels like a sort of hair shirt exercise, and then people don't see the point of it and don't support efforts to, for example, improve the building codes.
By the way, as a counterpoint to that, if we had it to do over again now, we would probably have gone with a company that has a factory floor where they can manufacture the building materials, because this would have made the dollars and cents work out better. This is pretty common in Europe. The only company I know of in the U.S. who does this is Bensonwood, although I'm sure there are others. You all might enjoy a visit to their factory next time you're in the area. :)
Another selling point for passive design is that it is just beautiful when done right https://www.nationalsolartour.org/
I dunno, I think ours is rather beautiful! :)
https://www.zillow.com/homedetails/373-Summit-Cir-Brattleboro-VT-05301/122415830_zpid/
Agreed just beautiful. Like I said passive homes look great and are super comfortable as you stated in the original post.
David - Thanks for this excellent episode to introduce your audience to PH. You may not remember it (or have realized it) when we had breakfast together in New Haven, but the place you stayed in for the Yale event, Hotel Marcel, is the first Passive House (PHI) certified hotel in the United States. (in addition to being 100% electric) It is super quiet, air quality is awesome and energy costs are only a third of what they would otherwise be. How did you like it?
Not David, but Andrea and I are Passive House enthusiasts too, so we've made a point of staying there on the way through. It's weird but fun. Honestly the Passive House aspect of it isn't at all obvious unless you're looking for it. Mostly what's interesting there is the design. I guess the fact that the Passive House-ness of it disappears is probably not a bad thing. :)
Seems like a terrible idea.
I used to think it was OK.
But that was before the biggest carbon emissions year ever, and the warmest year ever.
Net-zero is so inadequate. 1980 was the last time net-zero was a good idea. Today it's suicide.
If the GHG level stays where it is, the planet's habitability collapses quickly, starting with ocean-acidity driven collapse. Unless you can breath H2S it's time to stop screwing around with net zero buildings.
Only thing that matters now is when we get modular nuclear reactors manufactured.
They need to be dry so there is no fallout clouds to worry about, or containment buildings to delay.
They should be small enough to ship by land transport to repower existing coal and gas facilities. (Which is quite easy with 650C dry reactors of several designs.)
Where are the progressives for progress?
Will we destroy Earth because we are worried about the unintended consequences of saving it?
Oregon has an alternative "Reach" code that accepts Passive Haus standards as an option to the state energy code. Formerly you would have had to do both Passiv Haus design and review AND state energy code design and review, so a lot of redundant effort.
I'd also like to note that I believe one root of the Passiv Haus standard goes back to the 1977 Saskatchewan Conservation House demonstration project, which pioneered radical (for the time) ideas like airtight construction and heat recovery ventilation for a very cold Canadian climate. Despite some issues with innovative technologies, the overall success of that project inspired many others, for example, the staff at the National Center for Appropriate Technology in Butte developed and sold stock plans for what they termed "superinsulated" houses. It also pushed our Oregon solar community to become more rigorous about airtight construction and fresh air ventilation to improve performance of passive solar houses (topics that didn't get a mention at our "Solar '79 Northwest" conference). A lot of earlier thought and research went into our modern standards.
This was such an amazing episode, thank you! I'd love to hear more about updating current housing to passive housing standards: how it works, some experiences with it, if it can be done incrementally, how to order it.
Your "how to electrify your house" pod started with fixing your insulation. This is the necessary prerequisite that almost all houses are missing. There is so much territory here.
The comment about pre-fab also makes sense to run with, how does that work? Why doesn't the US allow it?
I really wish we talked more about this kind of thing in warm climates rather than cold climates. Everyone gets excited about keeping heat in during the winter, or applying heat pumps to more efficiently warm a home. But in many climates (and for many people), keeping cool in the summer is more important than keeping warm in the winter. For example for me in Indianapolis, we regularly get 95F+ and humid days in the summer but winters don't generally get crazy cold for more than a few days at a stretch. The same issue applies more broadly as people keep moving to the sun belt.
"We" have been talking about cooling load reduction in warm or hot or humid or all climates for 40 years. Smart summer-peaking utilities and PUCs and NREL and state energy offices, all.
Maybe start at https://buildingscience.com/bookstore?field_book_category_target_id=686
Also https://www.energy.gov/eere/buildings/building-america and you can get way in the weeds on all sorts of cooling efficiency and load reduction and related topics on humidity control or lack thereof.
Minimum AC efficiencies have been regulated up and up for 30+ years by the feds. Minimum standard windows reject solar gain to a much greater degree than back then.
Some of my earliest jobs were working for subs to the Cal PUC to develop and evaluate/model the value of efficiency measures. Many of the best values to the systems and the consumers were cooling load reductions and cooling system efficiency improvements because all CA utilities have been summer peaking. The utilities offered, and I assume still offer, substantial incentives for both new construction and retrofits. One reason American electric peak demand remained level for many years was probably just end-of-life replacement of cooling systems and windows, and some folks who have realized they should seal and super-insulate the cooling air ducts in their 130F attic.
Probably the reason this is not discussed as much right now is that GHG/kWh during cooling periods is dropping wherever solar is being added to the grid, which may even include Indiana, while there is a lot of heavy lifting to reduce the GHG of heating.
Great pod as usual.
The discussion was mostly about multi family homes in a cold climate, where PassivHaus makes the most sense, particularly considering the grid benefits.
However, they aren’t a magic bullet for all dwellings in all climates (and to be clear nobody on the pod was claiming they are). I’d doubt going full PassivHaus makes economic sense compared to a reasonably well-insulated conventional new build single family home with efficient modern heat pump HVAC in Southern California, for instance. This would be even more the case if California got serious about regulatory reform to make it easier to put rooftop solar in.
.
I am remembering your 2012 Tedx talk at Evergreen College:
"But we now know, to a fair degree of certainty, that if we continue what we are now doing we will face unthinkable catastrophe." Have this analysis changed?
I have to ask, David: do you now still think we can avoid unthinkable catastrophe? And if not, what purpose this diversion into housing energy efficiency? Surely we face unthinkable realities that cannot be mitigated by efficiencies or new technologies. What is your position?
Has any thought been given to exploring the role of Passive House with onsite generation and DC appliances, in conjunction with city block scale DC microgrids, might play in the energy transition as well as this topologies impact on national security.
As far as needing gas for DHW in multifamily (MF). First, here in the very cold Roaring Fork Valley, SanCO2 DHW heat pumps have been installed for MF and are working fine. There in Seattle, the Ecotope firm has integrated other CO2 cycle HPs for DHW with storage and demand response.
Beverly mentioned how LEED-rated buildings, presumably MF, had actual energy use all over the map. I'm a recovering LEED "Accredited Professional." The underlying standard, the ASHRAE Performance Rating Method, used energy $/yr instead of Btus or GHG emissions. Analysts could trade off better lighting, etc., for a less-than-stellar thermal envelope. And it used defaults for envelope section heat loss/gain, which in some cases required the analyst to over-estimate the thermal performance of steel stud walls with lots of corners and such. Also it compared energy cost of the proposed design to a convoluted "baseline." It was trying to not crimp the style of "creative" architects, who like all kinds of corners and overhangs and whatnot even in "affordable" housing. As I understand it, the PH std requires the design to just use less than xy Btu/sf-yr, depending on climate. Where sf is the floor area, so simple design is rewarded. From what I can see around here, once architects accept that, they still figure out how to add articulation and interest in other ways.
Really important discussion. In the middle of a housing shortage and affordability crisis and biodiversity crisis how do you, on top of everything else, ask developers to also embrace new restrictions on how they execute these urgent projects? And then there will be the really heavy lifting of upgrading existing building stock to be low emission. It is hard to imagine that simple GHG emission regulations are going to fix this, even given another 25 years. There need to be some carrots in the form of cost savings or livability and/or serious financial supports, even for the many people who really do care about climate change.
Passive House, or close to it, should be standard building code at least for multifamily. Less than 5% extra to build and the energy savings are forever. Here in NYC where the city is looking to reduce emissions and Department of Buildings has no problem imposing costs on owners in so many ways, it's almost criminal to allow inefficient buildings to be built.
Thank you so much for sharing Ted. We’re looking at building one at home as my office space/have remote workers come stay. As well as I work on a climate solutions recommender that aims to respond to any context or objective. So buildings clearly feature as a main focus area (42% of emissions across the board). At the macro level passive houses make a lot of sense. But at the micro level (consumer) cost is always the challenge. I can’t find low emissions cement at the retail level. The bits and pieces of assembly makes passive a challenging project. Availability and cost remain the consumer barriers. Energy codes will be the kicker I guess..
NREL.gov has been doing passive design research for 40 years. They have great information and design tools available to learn about and how to do passive design. https://www.nrel.gov/docs/legosti/old/2933.pdf https://www.nrel.gov/docs/fy01osti/29236.pdf https://www.nrel.gov/buildings/beopt.html
Thanks a lot!
https://studyhelper.com/argumentative-essay-samples
Great episode! I'm pretty sure that the embodied carbon analysis of a Passive House mentioned around the 40-minute mark is my article, which you can read here: https://en.tandemarch.ca/post/embodied-carbon-in-a-passive-house
In response to some of the comments about how PH would fare in different climates (mild, hot, etc.), the PHI standard is formulated as an "energy budget" with specific allocations in kWh per sq ft of floor area for heating, cooling and overall consumption. This means that in milder climates, you would need less insulation than in colder ones, since it will be easier to stay within the building's energy budget. I'm less familiar with PHIUS, but I believe that the principles are similar.
In hot climates, having a well-insulated airtight building enclosure will help reduce cooling loads. Think of how a thermos can keep your soup hot or you iced coffee cold: it helps maintain the temperature difference between inside and outside regardless of whether you're keeping heat in or out.
Thanks for covering this subject! Please revisit it as more information (ie, building PH in hot, humid climates) comes along for both new construction and retrofitting.
Before Texas’ shocking no-power winter a few years ago and even more so since, my pie-in-the sky wish has been to set myself up so that if my area experiences that level of breakdown, at least I won’t freeze to death or die of heat stroke (I’m in the Deep South and hurricanes are a yearly concern) in my own damn house. Years ago I saw a video on YT of a couple in a cold climate who had a mean temperature in their huge house of 60/65 F with no active heating/cooling necessary. Basically, their PH combined with heat from appliances, light bulbs, and body heat was enough. So that’s been my dream for normal use much less when sources of power aren’t functioning or available during an extended crisis.
I’m open to new construction and retrofit, but there’s no info to even say if I’d get the same benefits as experienced in northern climates, and seemingly no experienced architects or contractors in the region.
This pod finally got me to $ubcribe after listening in for a year.