The Tiny House Is Under Construction

The tiny house is under construction!

Here’s the nearly completed design for my first tiny house build. I came up with most of it, with help from my partner, Erica, who is also building a tiny house. My friend, architect John Fitzpatrick, set it all up in CAD, including the framing plan. Great to have real plans to work from. I bought the 26′ trailer from Iron Eagle Trailers in Gresham, Oregon.

tiny house construction

This is getting close to finished; just details left.

 

tiny house construction

The first wall sections are coming together on Erica’s project

 

Whole Tree Structures by Roald Gundersen

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Architect and builder Roald Gundersen builds what he calls “whole tree structures,” including homes and commercial buildings. Lately he and his team have been testing the design properties of branched columns at the Forest Products Lab in Madison, Wisconsin.

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Low-Tech and High-Tech Homes—At A Low-Cost

Substandard housing is a worldwide problem—and opportunity. Some places face natural disasters, such as earthquakes, hurricanes, and tsunamis, that wipe out peoples’ homes. Other places face huge population growth, with more and more people packed into crowded slums every day. How do all those people provide shelter for themselves?

As we’ve always done, many people build a home themselves, in the vernacular style. You also see plenty of creative options for healthier, more sustainable housing. Some make use of new technology, such as re-working shipping containers. Others use manufactured materials in creative ways. And still others use mostly low-tech methods with a dose of technology. But all over the world, people are building low-tech and high-tech homes—at a low-cost

Examples of Low-Cost Homes

This one is called The $500 House.

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Masonry Homes in the Vernacular Style

Locally made bricks are used all over the world.

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High-Tech But More Expensive

This M.I.T. project has been built. It looks good but the cost came to $5925.

 

Here’s a very impressive shelter made from a shipping container. With two fold-out wings, it goes from approximately 160 square feet to about 480 square feet. Great engineering!

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Not quite as cheap, but uses standardized components and goes together quickly.

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Low-Tech and Slow But Cheap, Functional, Durable, and Sustainable!

Here’s info about poly bags for earthbag building. Just $.06 each!

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Are Earth Bag Homes the Best Low-Cost Housing Option?

Some friends of mine travel to Nicaragua a few times per year to provide medical care and other help to people near the city of Matagalpa. Some volunteers build homes, too. The current home-building project builds small concrete-block homes at a cost of about $4000 each. Donations cover the cost.

Here’s an example of the existing homes:

Exterior view of a village home in Nicaragua.

Exterior view of a village home in Nicaragua.

Interior view.

Interior view.

And here’s an example of a new concrete block home.

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A new concrete block home.

Would earth bag homes be better?

I haven’t investigated earth bag and cob homes much, but I wonder if those methods would be appropriate for a project in Nicaragua. It seems that earth bag homes would be much more sustainable and far cheaper than concrete blocks. It seems that you could ship a few truckloads of earth bags to a village and build several homes for the same cost as one block home.

 

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Here’s a method that uses earth bag knee walls with bamboo framing. Teaching the villagers how to build this way would be ideal.

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And here are some examples of pretty nice homes:

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We Need Cheap Green Homes

A Cheap Green Home is a right-sized, energy-frugal house made from materials that represent the greenest practical choice. With a hefty budget, of course, anything is possible. A tight budget, though, demands ingenuity. And an affordable green home—the “holy grail” for homebuilding in this land of bloated plastic McMansions, is now a reality.

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This modern home built from a shipping container solves multiple problems. Factory assembly is more efficient, faster, and thus cheaper than traditional on-site construction. The foundation can be anything from a full basement to a system of posts. If you need more space, add more modules.

What is “green” anyway?

I think of “green” in terms of design elements, material choices, and methods. A green house builds in green features that are hard to retrofit later. It’s easier to site a house for passive solar gain than try to capture solar gain with renovations later. In contrast, you can add a photovoltaic system later with little hassle.

The green approach can be perplexing at times. Adding insulation enables the house to maintain a comfortable temperature with less energy. Some types of insulation, however, contribute heavily to global warming in their manufacture. You can see that it’s a balancing act, as each building has an impact on the planet. How small can we make that impact?

We can follow some standard practices:

  • Make it the the right size.
  • Make it tight.
  • Insulate.
  • Ventilate.
  • Use passive solar heating and passive cooling as much as possible.
  • Use the most durable materials you can afford.

Here are some examples of different approaches to a Green Home—cheap or not.

The “Standard” Green Home

You can build a remarkably efficient house with mostly standard design, methods, and materials. The Bircher Home in De Pere, Wisconsin, is a fine example. The house design incorporates passive solar gain and passive cooling, but looks like a conventional suburban house, apart from a small PV system and a solar thermal system.

Standard framing with 2×6 studs and cellulose insulation yields R-20 walls and R-44 roof. The house is well sealed, using foam and caulk, an infiltration barrier, and vapor barrier. A blower-door test rated the infiltration rate at 765 cfm, about half the typical rate at the time.

The result? The home uses 40% less energy than a comparable home in the area, and the $100/square foot cost, in 1999 dollars, is reasonable. You can get a normal-looking, high-performing house for not a lot of extra money.

The Advanced Green Home

The easiest way to get into a green home, if you can afford it, is to simply buy one from an innovative builder like Carter Scott. You’ll get a very green home that will perform well. And even though some of the green features, such as photovoltaics, add to the cost, you may be able to get an Energy Efficient Mortgage (EEM). This specialized mortgage increases the amount you’re able to borrow for a house that has energy-saving features that add to the up-front cost. The price? Market rate homes start at $289,900.

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Scott’s company, Transformations, builds zero energy homes in the Northeast U.S. They’re fairly small and a basic rectangular shape, with R-50 double-stud walls and R-64 roofs with spray foam and cellulose.

For heating and cooling, Scott has been using two mini-split heat pumps for the entire house. That’s a great cost savings over a furnace/AC system, and results in a simple, efficient, compact system. A photovoltaic system is sized to produce all the electricity each home needs. The homes are grid-tied, so excess electricity can feed into the energy grid.

What’s not green? His windows are cheap and they may not last long. The homes use vinyl siding, but you can go with fiber-cement siding for about $10,000 extra. Overall, Transformations is determining what works and what doesn’t in green home construction. And this approach is how we learn the most, from a production builder who tries new ideas and evaluates those ideas and the home’s performance after a year.

The Funky Green Home

The main floor of the NewenHouse.

The main floor of the NewenHouse.

Other ways to create a green home, cheap or not, I’ve covered with Jon Passi’s self-built, off-grid home, and with Sonya Newenhouse’s Passive House. Neither is actually cheap, but each is a functional and attractive way to a green, net-zero home. I can’t really evaluate how green they are from a materials standpoint, but Sonya’s house has a small footprint at about 25 feet square, so it’s definitely greener than a larger home. Jon’s home was framed with locally cut wood, which is a green choice. His house would be greener, in a way, if if were grid-tied, so his excess production could go to use and not to waste, but it’s very green as is.

Another approach is architect and builder Roald Gundersen’s “whole tree” building method. This approach uses unmilled, small-diameter, fast growing trees for the framing. Walls are often done with earth plaster, and roofs are often green. These are custom creations, but with extremely green materials choices.

A small, whole-tree building by Roald Gundersen.

A small, whole-tree building by Roald Gundersen.

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Another of Roald Gundersen’s whole-tree structures.

Resources

Bircher home

Pretty Good House

NewenHouse

Passi Home

99K House

Carter Scott

Seattle’s first net-zero home

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The House as Machine

I found these two articles interesting, and have been considering a similar idea recently: the house as machine. One commenter even used the same phrase.

Shades of Green

Solar vs. Superinsulation

My point is this: homes of the past did a better job, in some ways, of adapting to the changing weather. Houses in hot climates incorporated high ceilings and transom windows, with multiple windows arranged to encourage breezes to flow. Homes in cold climates incorporated small rooms around the heat source, and sometimes were earth sheltered. Actually, earth-sheltering is an effective strategy in all climates.

Back before we had abundant and portable energy such as natural gas and oil, buildings were built to be heated and cooled without machines specific to those tasks. There was no machine to add to the house that would provide abundant cool air, for example, and an affordable heater was a wood stove. Most of those homes were quite small by today’s standards.

Homes of the past certainly had problems, as air-sealing and insulation were not well understood. They tended to be drafty, and therefore well ventilated. Many homeowners created a fire hazard by extending their wood stove chimney in all directions to capture the most heat possible before the smoke escaped outside. People who could afford one employed a metal pan called a bed warmer, often filled with hot coals.

In the last few decades we’ve replaced good, regional design with more machines. More machines require more energy, and that leads us to the energy-guzzling homes of today, with homes all over the country adopting a more-or-less standard suburban architectural style (McMansion) that wastes energy like mad.

A home in the desert southwest, for example, should minimize the number of windows that face the southern and western sun. Most homes built in suburbia don’t consider such ideas, though, and are oriented to the street, with a huge air conditioner blasting away much of the year.

As the two articles state, the oil embargo in the 1970s got the efficient-home movement rolling, with great advances made. Builders and architects used superinsulation and passive solar design to cut down on energy requirements. These remain two of the most important components of efficient homes today.

A funky passive solar home with shading, solar gain, and thermal mass. A machine that works. Creative Commons license.

A funky passive solar home with shading, solar gain, and thermal mass. A machine that works. Creative Commons license.

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This earth-sheltered, passive solar home with photovoltaics uses only a fraction of the energy of a normal house. Creative Commons license.

The house as machine. Now it’s the house of machines—energy sucking machines. That’s not sustainable, but it’s easy to do so much better.

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A Visit to A Zero-Energy Home

A few weeks ago I attended a class called “The Zero Energy House.” Jon Passi taught the class for the Driftless Folk School, and is the owner and builder of the zero-energy home we learned about. The house is located a few miles outside of Viroqua, Wisconsin, and was built over the last five years or so.

Jon did a bunch of the work himself, including installing the photovoltaic and solar hot water systems. He said he spent about $180,000 and the house is off-grid, so there is a fair amount of hardware included in that price.

 

Here's a view of Jon Passi's zero energy home showing the front door, the sun room, and the solar thermal system to the left.

Here’s a view of Jon Passi’s zero energy home showing the front door, the sun room, and the solar thermal system to the left.

Construction

Jon built his home mostly conventionally, with poured basement walls, two inches of foam insulation below the slab, two inches of foam insulation on the exterior, and three inches of foam insulation on the interior. The solar hot water system feeds into a preheating tank, and then into a radiant heat system in the slab. There’s also a propane-fueled water heater, a small inline pump, and a backup boiler for baseboard radiators that Jon installed on the main floor and upper floor. The backup boiler system has never been used, but Jon said he installed it in case he wants to leave for an extended time during the winter sometime in the future. Jon reports that the radiant heat in the slab does an excellent job of controlling moisture in the basement, and I can attest that it was clean, dry, and warm on a rainy October day.

On top of this relatively standard basement, Jon built the framing with locally milled lumber. However, he said he would not do so again, as the lumber was not uniform in size, so he ended up milling every piece to size. You can imagine how time-consuming that was. The walls are insulated to about R-30 with open-cell spray foam, and the ceiling is insulated to R-50 with cellulose. Jon used Hardyplank siding and has been very happy with its durability and low maintenance requirements.

Heat comes from solar gain in the sunroom, and a woodstove on the main floor, in addition to the solar thermal heat in the basement slab. As for electricity, Jon installed a 3 kW photovoltaic system, with panels installed on the roof and on a ground mount. He said he really would need only about 1 kW for his needs.

Here's a view of the ground-mount PV on the left, the solar thermal system farther on, and the recycled windmill in the distance.

Here’s a view of the ground-mount PV on the left, the solar thermal system farther on, and the recycled windmill in the distance.

Water comes from a well located 100 feet or so from the house, up a small hill. The windmill is an old model, perhaps 100 years old, and was refurbished and sold to Jon by an Amish man who specializes in old windmills. It feeds into a concrete cistern, which will be full in just six hours on a windy day. The cost for the windmill and cistern were around $8000, and Jon reports that they work well and he’s happy with them.

My impressions

Two main ideas are sticking with me about Jon’s house: how normal it seems, and how feasible the whole project seems. I think most of us could pull this off.

Jon’s house looks utterly normal inside and out, with just a couple clues that it’s not. When you enter the main floor, you might notice the thick walls; the window sills seem to be about 12-15” deep. And as you walk around to the back of the house, you’ll see the photovoltaic panels and the solar hot water system. That’s about it.

Jon’s house, at about 2,500 square feet, seems oversized for one person. But it’s a more flexible size than a tiny home of 500 square feet, and is roomy enough to easily accommodate a family. And it seems that most families could handle this house just fine, as long as one person is willing to learn how to run the PV, solar thermal, and electrical systems. A smaller house would be cheaper to build and easier to heat, but this one may be easier to sell for use as a full-time home.

The main floor houses the woodstove, kitchen and dining area, and sunroom. The sunroom can be opened up and closed off with glass-paned French doors. I have had a similar space in one of my previous homes, and can attest that a properly designed sunroom can provide a great amount of free heat in cold, sunny weather. Without doors to completely close off the space, though, the sunroom will drain heat from the rest of the house after the sun sets.

The kitchen is the heart of the main floor.

The kitchen is the heart of the main floor.

The built-in dining table anchors the kitchen area; french doors to the sunroom are visible beyond.

The built-in dining table anchors the kitchen area; french doors to the sunroom are visible beyond.

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The sunroom, with thermal-pane windows, warms up nicely on sunny winter days.

The second-floor has a bathroom and a couple large bedrooms, with a large open area that Jon uses like a living room.

The second floor houses two bedrooms, a bathroom, and this living area.

The second floor houses two bedrooms, a bathroom, and this living area.

I like the solar thermal-radiant floor heat system, as the basement was quite comfortable. In warm weather you can simply shut it down and let the concrete mass cool. In cold weather the system can provide a substantial amount of heat, then automatically store it in the slab. I wonder about the cost, though, and its effectiveness in warming the second floor of the house. I also wonder if it would be cost-effective to install a loop for a wood boiler. It would be a redundant system, but would be functional when it’s cloudy. That’s a discussion for another day.

My main question in living with this house would be cooling. Sleeping in hot and especially humid weather is pretty sketchy for me. The bedrooms are upstairs, and I wonder if the windows can provide enough cross-ventilation. Fans can help a lot, but when it’s wicked hot out they’re just not enough. Maybe a mini-split system system would work to just cool the sleeping areas at bedtime. I’ve seen systems that draw only 900 watts or so in cooling mode, but more in heating mode. If that draws too much power from the PV system, I suppose I could sleep in the basement.

Diagram of a ductless mini-split heat pump system. Creative Commons photo courtesy of 3tonairconditioner.net.

Diagram of a ductless mini-split heat pump system. Creative Commons photo courtesy of 3tonairconditioner.net.

The main ideas to remember with this house are these:

  • A superinsulated and methodically air sealed house can look conventional yet work very well for creating a net-zero home.
  • Superinsulating, air sealing, and passive solar design make heating the home much easier.
  • The solar thermal and photovoltaic systems are more complex to manage than grid power, but it’s not that complex; just about anyone can learn how to run the systems in this house.
  • Jon learned it all when he decided to build his own house! “I had no idea you could even run an entire house off solar ’til I did it, and the same with solar hot water. The alt-energy stuff still amazes me, because I used to think the kind of house I now live in was an impossibility, or that it only was for super-rich people.”

What would Jon do differently?

After living in a house, there are bound to be some features that could be tweaked. Jon said that he would make a few changes, as well, if he were to build again.

“I’d put a masonry stove in it to heat it, and I’d probably make it underground, or semi-underground, plus I’d put the well farther up the hill so I’d have better, free water pressure. I bought lots of lumber for the house from the Amish, because I wanted to use local wood, but I had to re-mill every bit of it, so I would probably not use local sawmill wood next time. I guess, other than that, I would probably do lots of things the same,” Jon said.

And now for another viewpoint

Jon’s house is efficient, comfortable, off-grid, self-built, peaceful, and livable. And since technology is changing year by year, and as more and more people are building zero-energy homes, I think it’s helpful to evaluate how the systems work. You’ll find different points of view, even amongst building science professionals, so many questions still don’t have definitive answers. But I’m going to include a couple of links that make me think about the options.

I still don’t know if the solar thermal/radiant heat idea is efficient or a good idea. The consensus online at Green Building Advisor is that a radiant slab is overkill in a superinsulated house; is that true with solar thermal heating it? What about the idea that circulating pumps are too inefficient so off-grid homes don’t use radiant heat?

What if Jon had built without the solar thermal and radiant heat, and instead had used a mini-split system with extra PV to power it? He would also have cooling with this system. His backup system is a boiler and radiators, fed by propane. Could he eliminate that, as well? What would heat the house if he were gone for two months in the winter, and it was cloudy for days at a time? I think one or two propane-fueled direct vent heaters would cost much less than the boiler setup, and would be fine as a backup.

Well, in Jon’s case, he’s already at the mercy of the sun god, as he needs the sun for power and for hot water. That’s why he has a wood stove for heat, as well.

Solar Thermal Is Dead

Heating A Tight, Well-insulated Home

Will One Radiant Floor Heat Two Stories?

My tentative conclusion after reading all these is that solar thermal and the radiant heating are not optimal. A better solution would be more PV and a mini-split system.

And finally, I’m waiting for interior photos and will post them when I get them.

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On Designing and Building Solar-Oriented Cities

This article from Low-tech Magazine is an intriguing overview of designing passive solar cities, or solar-oriented cities, going back to the Greeks and the Anasazi, and with a lot of attention on Ralph Knowles.

Here’s a presentation with some of the same information:

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Do U.S.-made Passive House Windows Measure Up?

I found this blog interesting regarding window manufacturers in the United States. Do U.S. made Passive House windows measure up to windows produced in Europe? H Window Company, located in Ashland, Wisconsin, came out on top in the on-site test of four brands of windows.

Photo of Energate Window courtesy of H Window Company.

Photo of Energate Window courtesy of H Window Company.

What does it take for windows to meet Passive House standards?

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Which other manufacturers are commonly used in Passive House projects?

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More On Passive Houses, LEED-Certified Homes, and Net-Zero Buildings

Are high performance homes viable and appropriate for the mass market? Do they provide what their builders advertise? Are they worth the effort, or is it more greenwashing?

Why do I ask that? According to a 2005 report by the U.S. Energy Information Administration, buildings consume 48 percent of the energy—and over 70 percent of the electricity—used in this country every year. I think that’s a result of cheap energy for so long, but things are changing. “Energy independence” is a new theme, but it’s going to be challenging in the land of oversized McMansions.

Let's hope the time for these is past.

Let’s hope the time for these is past.

We’ve been accustomed to low standards for new construction and for remodeling for so long because of cheap energy. What if, during the housing boom of the last 15 years, homeowners and builders had emphasized energy efficiency instead of flashy items? I’m thinking of things like adding massive amounts of insulation, sealing the house against air leakage, and upgrading windows, rather than Viking ranges and granite countertops and showers with multiple jets, not to mention excessive square footage.

I’m not opposed to those elements (with the exception of excessive square footage), but I do think that more rigorous standards for energy and resource efficiency are more important. We must build structures that are more sustainable, energy efficient, and resource efficient first, and then add the other elements. Simply raising the minimum standards for housing is a huge first step.

Is the Passive House standard appropriate?

In my last post I explored Passive Houses. I like the Passive House standard because it’s about designing efficiency into the home with a heavily insulated, nearly airtight envelope. It’s so well insulated that the incidental heat produced by bodies and appliances can provide all the heat needed in some climates. Even in colder climates Passive Houses dispense with a standard HVAC system in favor of a heat- or energy-recovery ventilator and a small backup heater.

The Passive House standard is defined by results, not by methods. There are three benchmarks to hit: for air-tightness, for heating, and for overall energy use. There are some principles to follow as well, such as eliminating thermal bridging, and superinsulating, but they’re a means to an end. The three benchmarks are tough to achieve, though, so you tend to see the same methods employed to reach the standards.

A Passive House in Austria shows the typical simplicity of the design.

A Passive House in Austria shows the typical simplicity of the design.

A Passive House is quite simple but not easy, and the house either hits the target or it fails to. Thousands have been built in Europe and more are underway in the U.S., where the standards are under review because of the energy load required for dehumidification. We may see the standards tweaked to address regional differences such as high humidity.

In any case, Passive Houses have shown that it’s possible to drastically cut energy use in a home—up to around 90% in some cases compared to a standard American home with a HERS rating of 100—with building design, rather than additional hardware. Passive vs. active techniques, essentially.

Other standards for improved homes exist, as well. The U.S. Environmental Protection Agency runs the Energy Star program, which requires homes to use at least 15% less energy than a home built to the 2004 International Residential code standard, which results in a HERS score of 85 or better. That’s better than nothing, but doesn’t seem very ambitious. A Passive House should score in the range of 20-30. A net-zero home scores at 0.

LEED takes a different approach

The LEED for Homes standard, in contrast to Passive House, addresses a variety of factors in building an environmentally friendly home. This standard, from the U.S. Green Building Council, aims to “promote the transformation of the mainstream homebuilding industry toward more sustainable practices. LEED for Homes is targeting the top 25% of new homes with best practice environmental features.” The standard will be updated in 2013.

LEED for Homes, which requires independent, third-party verification, focuses on eight areas: indoor air/environment, site development, site selection, water savings, materials selection, energy efficiency, resident awareness of a home’s performance, and innovation. By following the LEED for Homes approach to these factors, you can build a home that:

  • provides a healthy indoor environment with few pollutants and abundant fresh air
  • minimizes water use
  • uses more sustainable materials and uses them efficiently, minimizing waste
  • minimizes energy use
  • is sited and built so as to minimize its environmental impact, and to have efficient access to needed services, businesses, etc.
  • costs less to operate and is sustainable over the long term.

The U.S.G.B.C. has targeted the standards to the top 25% of new homes, but other groups are applying them in the mass market. This is a fantastic idea!

Habitat for Humanity in Kent County, Michigan, has committed to the LEED Gold standard of certification. That’s not as good as Passive House standards for energy use, but it is impressive, especially since Habitat homes are meant to be affordable. (I have not seen a cost/square foot or sales prices for their projects, but have asked for that information. I’ll post it when I see it.)

This page at their site provides a good summary of LEED standards with some research done by the Alliance for Environmental Sustainability. The AES reports that annual savings on electric, heat, and water should total at least $1000 per home. Other Habitat groups around the country are taking the same approach, including LEED townhomes in St. Paul, Minnesota, which I think is a great option, as not everyone wants or needs their own yard and accompanying maintenance. Plus, townhomes can be built to a higher density, making better use of buildable lots, with the potential of preserving existing open space.

I’m encouraged to see the progress LEED, Passive House, and other sustainable techniques are making in improving housing in the U.S. And while no standard can be perfect in every situation, it seems to me that the ideal house project would use the performance standards of the Passive House, and the sustainability criteria of LEED.

Next I’ll have a look at net-zero homes.

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