Building Green

At some point, I hope to own a zero energy home. (My wife is not as enthusiastic, so I have some persuading to do). Until then, I will cheerlead for those who are building green. I have previously written about my friend Jerry Unruh’s solar home in Colorado.

Now here’s a very low energy home in Fort Worth. You may have heard of Heather’s Home, which has been featured in numerous media publications and has won lots of awards.

The home’s features are:

  • Structural Insulated Panels (SIPs)
  • High Efficiency Heating and Cooling System
  • Solar Hot Water System
  • Energy Star Doors, Windows, Appliances, Lighting
  • Fluorescent and CFL Lighting
  • Non VOC Interior Finishes
  • Green Sustainable Products – Trim, Countertops, Floor Coverings, Finishes, etc.
  • Fiber Cement Siding
  • Passive Solar Design
  • Proper Shading of Windows and Doors
  • Attic Fan for a “Thermo-Siphoning” Effect
  • Metal Roof
  • Organic Landscaping
  • Rainwater Harvesting

I would really like to know more about that heating and cooling system, but I couldn’t find anything on the site. Maybe one of those news articles talks about it. The site says her average heating and cooling bills are expected to be about $15 for this three bedroom, 2,000 square foot house. It can get terribly hot (and humid) in Fort Worth in the summer, so it will be interesting to see how she fares then. I suppose with a couple of solar panels, she may have been able to have a truly zero energy home. That would be an incredible achievement in that climate. I wouldn’t have thought you could do it without being miserable.

You can find a wealth of information on building green, including best practices for various parts of the U.S., on the Department of Energy’s Building America site. Even if you can’t afford to do everything at once, there is a lot of good information on projects that can reduce your energy usage.

28 thoughts on “Building Green”

  1. I’d like a zero-energy home, but I am kind of put off by the fact that most of us who retire out of southern California also move to colder places.

    The opportunities for “infill” zero energy homes are very low.

    (I went mountain biking yesterday in shorts and shirtsleeves.)

  2. Odo – I have thought about this a lot lately too. For my retirement home I will be able to use my engineering skills to design something that is much more efficient.

    The builder picks the HVAC, appliances, and energy efficiency. He is trying to maximize profit at closing and less concerned about total energy costs. For a modest cost increase you could upgrade the wiring, HVAC, and other systems to be a bit more energy efficient.

    We are looking at adding zone cooling to our house. At night we could just cool or heat the bedrooms instead of the entire house. It is very expensive to retrofit an existing home.

  3. How about some “Truth in Advertising”?

    A true “zero energy home” is a cave with no fire in it. If we have to dig a hobbit-like hole because there is no convenient cave, then it is no longer a “zero energy home”.

    When people say “zero energy”, they are too often ignoring the energy invested in building the home and the energy invested in annual maintenance.

    We have to evaluate the total system, not simply the energy used for heating & lighting. How long does it take to recover the additional energy invested in all the features of one of these “zero energy” homes versus a similar conventional home?

    I’m not knocking the desire for energy conservation, which is good. Simply pointing out that the house with the lowest heating/cooling energy requirement may NOT be the house which minimizes total life-cycle energy consumption.

  4. Maybe it’s better to call it a zero Delta energy home (i.e. it produces as much as it consumes). What would argue that a truly green house recycles what is there. Find a home in some urban neighborhood, rip out the interior, add lots of insulation, use recycled materials for flooring, walls etc.. Then watch the fun when you try to get planning board permission to cut down the trees shading your solar panels, even having solar panels on the roof at her house if the roof does not line up perfectly north-south, and don’t even think about putting up a tower for a wind turbine.

    While it may cost more money to go this route and take longer to build, reusing existing property and land should minimize environmental impact. Of course, this all get shot in the head if you have lead paint all over the inside but you can walk away from that property.

  5. I agree with Kinuachdrach, the total cost of inputs, not just the “operating costs” have to have equal weight.
    Project 14 on my “do list” includes a solar clothes dryer, to replace the “solar dryer” we already use 90% of the time, the clothes line. I already have the materials purchased. Essentially it is low low cost solar collectors that heat air, with that heated air brought to a rotating drum. It would be great to have that rotation “powered by the sun”, but it is uneconomic, even at 2x the rate of charge for mains electricity.

    This is an example of how the equation should be done, not with a “zero outside” cost goal, but a “minimum cost” goal.

  6. Some years back,I had the opportunity to buy a 4 bedroomed property at a very much reduced price.

    It is situated in a traditional west England, Somerset village, with pub, church and post office/shop.

    The property was built after WW2 and once was owned by the local council.

    However, due to a major structural flaw, which affects all the 8 properties in that street, it is now in need of some major internal structural work.

    This will entail removing the inner wall brick skin, repartitioning the rooms for a better layout and replacing the inner wall with a highly insulated timber frame structure – but retaining the outer local stone walls.

    The room repartitioning work will allow the whole of the ground floor area to be insulated and underfloor heating installed.

    The removed inner brick walls will be recycled and used to build a detached garage with a south facing roof for solar water heating and possibly some pV.

    Whilst I was first concerned about the magnitude of the work involved, when I discovered the structural defects – I now see this an enormous opportunity to create a low energy eco-home within a rural village location -something that I could not afford by any other means.

  7. I suppose with a couple of solar panels, she may have been able to have a truly zero energy home. That would be an incredible achievement in that climate. I wouldn’t have thought you could do it without being miserable.

    No misery required :). If you ever get out to Colorado, be sure to check out the RMI headquarters in Snowmass. At elevation, where lows get to -40, their heating system consists of a small woodstove which they use only a few days a year. And they have an integrated greenhouse where they have harvested bananas in midwinter.

    This building was, in truth, fairly expensive to construct. But it was done in the early 80’s, when, for example, high performance windows were rare and expensive. A similar level of performance is fully achievable, and much more economically, these days.

  8. $15 to heat/cool isn’t much. Figure $0.10 per kWh that is only 150 kWh per month. That implies to me some kind of ground effect heat pump. Given that during the summer nightime temperatures in Fort Worth can be as much 75 or 80 F traditional A/C is going to cost you a lot more in power even if it is 18 or 20 SEER.

    Passive solar heating is a LOT easier to do than cooling. You can’t compare homes in the rockies to Texas. It gets damn hot in the summer here.

  9. I agree with Kinuachdrach, the total cost of inputs, not just the “operating costs” have to have equal weight.

    Fair point, but the reality is that building operations use vastly more energy than what is embodied in the construction materials. Per EIA, building operations (all sectors) is about 40% of annual national energy use, while embodied energy in construction materials is about 8%. And of course the embodied energy is paid once, while the operating energy occurs year after year, so the integrated impact over time favors increasing embodied energy to reduce operating energy.

    Also realize that most green building options don’t imply a huge increase in embodied energy. Solar PV has a big embodied energy impact, but other technologies have embodied energy margins that are much smaller, or frequently zero or negative.

    For example, the marginal increase in embodied energy for a Turbocor centrifugal chiller with magnetic bearings vs. a recip chiller is going to be fairly small — both machines contain about the same amount of materials — while the operating energy difference can be 50% or more.

    Better, spending more money on design up front can reduce your total embodied energy (and capital cost) by removing unnecessary capacity. If you can reduce the chiller from 200 tons to 50, that’s a net win on the embodied energy side as well as on the operating energy.

  10. RR-
    You have stepped into a very interesting topic.
    I happen to doing some PR work for a shop that specializes in “green architects.”
    Green has become mainstream in the last three years. Every builder and architect is going green. There is something referred to as a “LEED” rating, which rates a build’s greeness. I would say the majority of new major projects are vying for the green label.
    There is an incredible amount of square footage that will be built new, or revamped, in the coming 20 years.
    Long story short: Expect the built environment in the USA to use less, not more, energy 20 years from now.
    New lighting systems are amazing, LEDs and other light use 10 percent of energy used before. Incredible new glass windows screen out heat but not light. Seems like magic, but I have seen such windows with my own eyes and skin.
    This is yet another reason why we will not have an energy shortage, or crisis. Energy demand can easily flatten, for decades, while living standards go up.
    To KingofKaty: I lived in Texas for two years. It is hot, and humid, except when it is damp and cold.

  11. the reality is that building operations use vastly more energy than what is embodied in the construction materials.

    Sorry, greenengineer, you are (to be polite) way off base on this one.

    The US builds only a certain number of homes/hospitals/etc each year, and that takes 8% of annual national energy use (says EIA).

    And we operate the cumulative of all the buildings constructed in the last 20 – 50 years years using 40% of annual national energy use.

    Those figures are too ill-defined to prove anything, but they probably suggest that something like 80% of the life cycle energy consumption of an individual building is the energy used in constructing it.

    So if we want what is ludicrously mis-called a “zero energy home”, we should be paying a lot more attention to the energy used in its construction than to the energy used in its operation.

  12. Since I’m currently a community college HVAC/R student I was also curious about the mechanical systems.

    I found mention of PEX on the plumbing page provided by Viega. Seems like Heather’s likely got radiant heat. Cooling wise all I could see was the whole house fans.

    I’ve installed a whole house fan while living in the FL panhandle in a smallish ranch. Considering the apparent extensive architectural work resulting in 2 whole house fans, I suspect in her location that may suffice.

    Much of the heating/cooling load mechanical systems would normally handle have probably be alleviated through what looks to me, well considered passive design elements.


  13. The first place to start this sort of research, in my view, is to study the types of traditional housing originally used in the region you are going to build in. It’s amazing how premodern people solved a lot of problems by choosing certain materials and building in certain ways.

    Once I was traveling through the American Southwest in midsummer. In the hottest part of the day I had the opportunity to take refuge in a building with stone walls about 2 feet thick. When I first walked in, I could have sworn the place was air conditioned. No such thing, the owner assured me. The thick rock walls kept the building cool during the day, and released the heat at night.

    By contrast, traditional Japanese architecture is light wooden construction with lots of open space and few walls (just panels that open and close), with low overhanging eves and high (or no) ceilings. That is suited to the temperate humid climate.

    Once you’ve checked out traditional housing, incorporate the latest technology for further enhancements.

  14. Those figures are too ill-defined to prove anything, but they probably suggest that something like 80% of the life cycle energy consumption of an individual building is the energy used in constructing it.

    Try again.

  15. Keep in mind that vast square footahes are going to be retofitted or rehabbed in next 20 years, I think roughly equalt to the amount built new.
    The rehabbed space does not cost as much to build as new, and usally will consume far less energy, after rehab (since green is a hot rehab fad).
    Oil sinking again. There is the spectre of a recession, but soon the market will learn that demand is going down, not up.

  16. Well lets see if you can poke some holes in this post over here:

    You know, I need to get over there and register. Lots of times I wanted to say something, but then didn’t want to take time to register.

    I notice he mentioned a study by Booz Allen Hamilton. I have seen them lurking on this blog lots of times, but never knew why. Now it makes more sense.

    By the way, I think his 2,000 gallons per acre is probably approaching the theoretical limit (based on solar insolation) of what you could get if you mowed all of the biomass to the ground and could convert it without any energy inputs. The number just isn’t rational. (If I weren’t so pressed for time, I would work it out. Maybe some other time).


  17. If you’re interested in getting more info on this home, I might be able to put you in contact with the homebuilder. I happen to know the guy.

    I would be particularly interested in knowing what kind of cooling system is in the house. Also, how much has business been impacted by the housing slowdown? The Dallas area isn’t looking too good right now.

  18. Kinuachdrach,

    Actually, it’s you who are off base.

    From Architecture 2030, which gets its numbers from the EIA and the US Energy Research and Development Administration:

    There are ~ 300,000,000,000 square feet of building stock in the US.

    These buildings consume about 40 QBTU per year, or 133,333 BTU/sf (0.134 MBTU/sf).

    The annual embodied energy of building materials and the energy used to construct buildings is estimated at 1.146 MBTU/sf of building for new construction and half of this for renovation.

    So, on average, a new building has about 10 years worth of its operating energy going into construction, while renovations hit this point at about 5 years.

    Since most buildings are designed to last 30-100 years, operating energy dominates the equation. I’m disregarding cheap speculative housing stock that’s maybe good for 10 years, but that never should have been built that way in the first place.

    Obviously, these are averages which will have an enormous standard deviation between different building types and climates. But these figures suggest that there is alot of room to invest additional embodied energy to save operating energy.

    Aside from this, as I previously noted, good energy-efficient design doesn’t have to have a large embodied energy premium, and can easily have a NEGATIVE embodied energy margin. If the designer spends twice the embodied energy to save half the operational energy, it’s a sign that the designer is suffering from a lack of creativity (in most contexts). And it’s still a net win, for the planet if not economically.

    An awful lot of the energy use in buildings is a direct result of engineers who are either lazy or too busy. These are cultural, expectation-based, and economic factors which are hard but possible to change.

  19. Regarding “zero energy” buildings: Yeah, that misuse of the term rubs me the wrong way too. The closest accurate statement of a relevant metric is “carbon neutral in operation”, which is the benchmark that Architecture 2030 uses.

    “Zero Energy” is, like so many things, an imprecise phrase that is essentially a marketing tool for representing an idea to the vast majority of folks who are not engineers. And a building that is actually a zero-net-operating-energy consumer is still a big deal, and a major step in the right direction, so I don’t really have a problem with it, aside from it offending my sense of purity.

    On the other hand, California has started using the term “zero energy” to describe homes that use 40% less energy than baseline, and that pisses me off because it makes the term meaningless.

  20. Lastly, if you want to talk about a building that makes minimal impact in both construction and operation, then the Living Building Challenge is the standard you want to look to. It’s been developed by the Cascadia chapter of the USGBC, and hopefully will someday become the successor to LEED as the metric for green building practice.

    For now, though, it’s a barely-achievable standard and there are no buildings that satisfy it that I know of. Carbon neutral operation is a good first step. Let’s not make the perfect the enemy of the good.

  21. Oh, and I would like to encourage you to register at Gristmill. They have a good community there, and some very good discussions. Quality is highly variable, of course, but generally better than average in the green blogosphere. Your voice would be a very welcome addition.

  22. GreenEngineer wrote:

    Actually, it’s you who are off base.

    You are right. I stand corrected. That’ll teach me to do mental arithmetic when I am tired!

    Thank you for pointing out my error.

    Of course, we still agree on the underlying point — zero operating energy does not mean a “zero energy house”.

    And then there are all the other factors to consider. Build a new house and it is likely to be where land is available in the outer suburbs, which means longer commutes and therefore higher transportation energy use by the residents. Cut down a mature tree to let sunlight hit those roof solar panels, and a carbon sink has been transformed into a carbon source. Etc.

    Unless we get people to think about what the system boundaries truly are, renewable energy is going to continue to disappoint.

  23. As I have read these comments I have seen a lot of very good ideas. Let me add one of my own. The only part of a green home not a zero energy home that I find to be important is to have it built in such a manner as to not allow any heat build-up in the home to escape to the outside. For me it is easy to have a home that runs totally on it’s own power source. What I do not understand is how to dispose of the heat from the inside of the home while at the same time running my air conditioner at full blast. Although the heat I exhaust from my home does not pollute and cause global warming, does it not contribute to warmer outside air and therefore a warmer planet?

  24. This may well be a “zero energy” home, but not much is mentioned about “Heather’s” lifestyle. I would expect that “solar clothes dryer” is also on the list of amenities. (This is the hi-tech term for what my grandmother called a “clothes line”.)

    So-called “zero energy” homes can only be achieved by corresponding lifestyle adjustments by the residents. We should be up front about this.

    There is very little discussion on this site about the true scalability of solar power. For the average reader, all of the listed amenities will not be sufficient to achieve zero net energy usage.

    We should be realistic about the limitations of the solar solution. It is 50 to 100 years away, and the longer we pretend otherwise, the greater security and environmental risk we face.

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