March 13, 2008
Big Energy Savings Possible By Better Building Design

A commission sees the greatest energy conservation potential in better building design.

Promoting the green design, construction, renovation and operation of buildings could cut North American greenhouse gas emissions that are fuelling climate change more deeply, quickly and cheaply than any other available measure, according to a new report issued by the trinational Commission for Environmental Cooperation (CEC).

I've long thought that cars get a disproportionate amount of attention over the energy they use. We should focus harder on building efficiency over car efficiency for a few reasons. First off, buildings last longer and cost more. Decisions made about building construction stay with us for a longer period of time than decisions about which car to drive. As the effects of Peak Oil hit with full force we can shift to motorcycles, bicycles converted to electric power, and very small cheap cars. But houses and office buildings can last for 100 years and longer.

A second reason to focus more on buildings is that most measures for making a building more efficient (e.g. better insulation and sealing, multi-pane windows facing southward, ground sink heat pumps) do not make buildings less comfortable. In fact, they can make buildings more comfortable. By contrast, most people prefer bigger cars for greater comfort and safety. They won't give up the big cars until gasoline goes up even higher.

Very few of the new buildings get built with the most efficient designs possible.

North America’s buildings cause the annual release of more than 2,200 megatons of CO2 into the atmosphere, about 35 percent of the continent’s total. The report says rapid market uptake of currently available and emerging advanced energy-saving technologies could result in over 1,700 fewer megatons of CO2 emissions in 2030, compared to projected emissions that year following a business-as-usual approach. A cut of that size would nearly equal the CO2 emitted by the entire US transportation sector in 2000.

It is common now for more advanced green buildings to routinely reduce energy usage by 30, 40, or even 50 percent over conventional buildings, with the most efficient buildings now performing more than 70 percent better than conventional properties, according to the report.

Despite proven environmental, economic and health benefits, however, green building today accounts for a only small fraction of new home and commercial building construction—just two percent of the new non-residential building market, less than half of one percent of the residential market in the United States and Canada, and less than that in Mexico.

I am expecting energy price rises to drive a push toward more efficient building construction. If you are thinking about building a house or commercial building think about future energy prices when you choose your design.

Share |      Randall Parker, 2008 March 13 08:59 PM  Energy Policy

greg said at March 14, 2008 7:07 AM:

I'm finishing my "green building" now (ICF technology), and its thermal behavior so far is nothing short of fantastic. It maintained around 50F inside through the entire winter (New England), and its only heat source was an old oil furnace heating another small house adjacent to it (i.e. the new house used only heat losses from that furnace). I also plan to have a geothermal heat pump installed, and I'll have a solar heat on the roof assisting it. I'll let you all know the results next spring.

Brock said at March 14, 2008 9:58 AM:

The reason that this is still a problem though is that increasing efficiency increases up-front costs to the builder and the sale price per square foot. Buyers who quickly scan down a list of prices without looking further into the matter pass up these opportunities. It costs them in the long run to do this, but people generally pick lazy over rational.

I've long been a proponent of taxing pollution and other undesirables. A nice big up-front sales tax on real estate (both new construction and resale) that is based on the expected energy usage of the building would go a long way in correcting for the somewhat irrational behavior of real estate purchasers. A similar tax on retail electronics, appliances and white goods (washers, dryers, refrigerators, etc.) would also do wonders in this respect.

Tj Green said at March 14, 2008 5:51 PM:

Air drawn from underground pipes, using solar powered fans, would cool a house in summer,and glass on the south side of a house would heat it up in the winter.

Randall Parker said at March 14, 2008 7:43 PM:


Can an entirely passive design keep a building above freezing?

What is ICF technology?


On the south side what is needed is an outside covering of multipaned glass with black material behind it to capture all the light as heat. A passive circulatory system could then bring the warmer air inside. The air vents to this outside layer could be closed at night.

Engineer-Poet said at March 14, 2008 8:39 PM:

RP just reinvented the Trombe wall.

I recall an article (in Home Power?) about a passive-solar house in Vermont which stayed in the 50's in winter despite cloudy conditions and no supplemental heat.  I would call that a success.

beowulf said at March 15, 2008 2:07 AM:

This isn't difficult, just add the green standards to the local building codes. If "green design" is presently cost-prohibitive, you could limit the green requirements to no more than, say, 10% of the total construction cost. So a $200,000 house wouldn't have the same environmental requirements as a $1 million house. In theory, building codes are local matter, but Uncle Sam has sort of blown up the whole federalism idea by the use of revenue sharing.

According to a 2004 Gregg Easterbrook TNR article, Uncle Sam sends state and local governments over $400 billion a year. In other words, you can explain away the federal deficit because of the federal government subsidizing states and cities. So Uncle Sam can condition a portion of its funding on states setting green building codes (its because of such strings on highway money that every state has a 21 year old drinking age).

greg said at March 15, 2008 7:57 PM:


Yes, I believe a passive heat design can keep a house above freezing in winter. This particular house has a full basement where the slab is below grade by ~6 ft, so it's a moderate source of underground heat. I'm planning to use the solar heat that is absorbed by the roof surface for heating the interior, but at this stage it's not clear how much of it would be useful without installing thermal solar panels (which probably don't qualify as "passive"). Using the thermal solar might bring as much as 100 KWh per day at average in winter, i.e. around 16 000 btuh - that's certainly not enough for heating, but would cut energy use quite a bit.
ICF stands for "Insulating Concrete Forms". It's a building technology where concrete is poured into a wall consisting of two layers of extruded polystyrene. In addition to providing a good insulation, it also has a high thermal mass allowing it to accumulate heat during day and dissipate it during night - which eliminates need for heating and cooling in spring and autumn.

Brett Bellmore said at March 16, 2008 6:30 PM:

Heck, around here (Southeast Michigan.) the ground temperature is above freezing year around, just three feet down. (The "frost line".) Take that as an existence proof that passive heating can keep your home from freezing. The greater challenge is keeping it comfortable. Which requires not just taking in and retaining as much heat as possible, but also temperature regulation. I don't see how you do that passively, though doing it without very much in the way of power is certainly feasible.

Given the extent to which my home is passively heated by ground heat through the basement, I've wondered about the feasibility of using heat pipes to bring a large chunk of soil directly under the house up to peak summer temperatures. Too bad thermal diodes want to passively *extract* heat from the ground, not store it there.

solardude said at March 17, 2008 8:25 AM:

Greg's ICF house works because ICF is outstanding in preventing air infiltration, with that thick layer of concrete sandwiched by insulation. I've worked with both SIP (structured insulated panels) and ICF, and generally prefer SIP, though ICF does have its advantages. The usual criticism of ICF is that the thermal mass is in the center, surrounded by insulation, when the building's heating and cooling performance would be better if the thermal mass were on the interior side. SIP provides no thermal mass, leaving it to the builder to add thermal mass---usually in the form of a concrete floor with radiant heating.

In addition to ICF walls, Greg's house also has a basement, which is surrounded by a large mass of earth. This earth berm provides additional thermal mass, though for the basement, not for the above ground portions of the house. Earth berming is the surest way of maintaining the interior temperature of a home.

On the south side what is needed is an outside covering of multipaned glass with black material behind it to capture all the light as heat. A passive circulatory system could then bring the warmer air inside. The air vents to this outside layer could be closed at night.

This is a solar air heater configuration, which has enormous COP (coefficient of performance). During the day,it can collect enough heat to warm the entire room behind the air heater. Most people usually try to store the heat for the evening as well, so they pour a concrete floor, and provide an overhead fan to force the heated air to the concrete for energy storage. This set-up is very energy efficient, though it requires a fan. The only drawback is 1) the solar air heater is opaque, so devoting a large portion of the south-facing windows to solar energy collection, would obstruct some views of the outdoors, and (2) the floorplan of the house would have to be largely open to distribute the heated air, so the inhabitants give up some privacy. Solar air heaters are typically used in garages and workshops for these reasons.

solardude said at March 17, 2008 8:32 AM:

Given the extent to which my home is passively heated by ground heat through the basement, I've wondered about the feasibility of using heat pipes to bring a large chunk of soil directly under the house up to peak summer temperatures. Too bad thermal diodes want to passively *extract* heat from the ground, not store it there.

Ground-source heat pumps have a COP of about 3. That is, for each watt of energy used to drive the pump, you get 3 watts of usable heat energy. They are certainly a good choice for low-cost heating, though they are often used only as auxilliary heating for solar homes.

solardude said at March 17, 2008 8:42 AM:

RP just reinvented the Trombe wall.

A Trombe wall consists of a large thermal mass behind a plate of glass. The glass collects solar energy and stores it in the wall; the heat in the wall then radiates to warm up a room behind the Trombe wall. RP notes that the air should be circulated. Openings or ducts at the top and bottom of the Trombe wall are usually created so that heated air ciculates in a thermosyphon fashion, so that this design acts as both solar air heater and radiant heat generator.

The main problem with Trombe walls is that at night all the energy collected in the thermal mass leaks out to the exterior, unless the glass is covered with insulation. A material such as aerogel, rather than glass, solves this problem as it transmits light, but is also an extremely good insulator.

persiflage said at March 18, 2008 5:34 PM:

A study done in Sweden, in 2006 I believe (I read about it in The Economist), purported to show that the the three most valuable anti-greenhouse gas actions that could be taken (that is, those yielding the greatest reduction in CO2 emissions per unit of money spent to achieve it) were 1)improvements to the construction and insulation of commercial buildings, 2)improvements to the fuel economy of commercial vehicles (that is, over the road trucks and off-road construction equipment) and 3)improvements to the efficiency of commercial lighting systems in offices, institutions and factories. The Economist article seemed to imply that the really neat thing about these three actions to increase energy efficiency was that all of them give great bang for the buck, directly benefit the owner of the property or vehicle in question, and none of them require a permanent government bureaucracy to implement.

remy said at May 6, 2008 11:55 PM:

I really need help becasue we have a home project and my dad is getting angry at me. I really need to get it done! Well it's about this house or watever and we have to design it and make it, it is about saving energys and I need some informations so please help me!I'm Remy Harvie and I'm 10 years old please help me

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