28 August 2009

Green Blog, Green House

As we have explored building materials, design, components, and techniques, we have gotten really excited about building a "green" house. It just makes sense that, given this opportunity to decide what to put on this patch of earth, we would make it as socially responsible and minimally burdensome on our world as possible. Little did we know when we started down this road that Austin is a (if not the) leader in green building. In addition to it generally being kind of an outdoorsy hippie town that embraces this sort of thing, our hot climate and resulting energy needs have led the city and its municipally owned utility, Austin Energy, to devise creative strategies for reducing our energy use. Instead of having to build new power plants -- a very expensive undertaking -- Austin Energy has chosen to offer a myriad of incentives for individual customers to adopt energy-saving measures. For existing homes, they offer sizable rebates and zero-interest financing for all sorts of energy-efficient upgrades, such as new air conditioners, water heaters, insulation, appliances, etc. To reduce our water needs (Austin is currently in the second year of a major drought), they even give out free high efficiency toilets. Since codes tend to mandate these more efficient systems for new construction, the city isn't as generous with new homes, but they do have big rebates for solar panels and limited other energy-efficient components. I don't know how much they have spent on rebates (or how much a power plant costs), but they have already saved themselves the need for a whole power plant through these programs.

Austin Energy also offers a quarterly all-day workshop, Green by Design, for people considering remodeling or building homes. The workshop is a part of the green building program, which rates green houses from one to five stars. Our house will probably get four stars (the things you have to do for five stars get pricey, and we're not the Rockefellers). In addition to what you would expect (recycling of construction waste, efficient installation of systems, etc.), some of the things they give points for are things you wouldn't expect:
  • not having carpet (which wears out and creates waste when it's replaced)
  • building on a lot where utilities have been in place for at least 25 years (infill construction in developed areas theoretically reduces urban sprawl)
  • termite-proof construction, such as steel studs or barrier systems (so that the property does not have to be treated with chemicals that would seep into water sources)
There are even some things that aren't really about green building at all -- lever door handles, for instance, which are a component of accessible design (maybe this is like carpet; if a disabled person moves in later, the old handles won't end up in a landfill).

Anyway, the workshop covers a lot of this stuff. Unfortunately, we had just missed the spring workshop when we started thinking about our house, and by the time we went to the workshop two weeks ago, we had already discovered much of what they presented. We did learn some new things, though. For instance, we've been trying to decide what kind of water heater to use. The trend right now is tankless water heaters, but studies have shown that they don't save as much energy as you would think, and they're pretty pricey. Plus, since we're going to be installing enough solar panels to hopefully cover our electrical needs (there are HUGE Austin and federal rebates right now), it's hard to justify installing a gas appliance when electricity will be free and we don't know where the price of natural gas may go. A builder planted the seed of a solar water heater in our minds, but we have certain reservations about that, too. Green by Design introduced us to another option, which might be a winner: the heat pump water heater. It extracts heat from the ambient air and uses it to heat the water in a traditional tank. Even in the winter when the air is freezing, there is enough heat in the air to heat the water more efficiently than any other kind of water heater. Pretty cool, huh? (Since our house is about 70 feet wide, and the water heater -- near the master bathroom -- is on the opposite side from the other bathrooms (with the kitchen in the middle), we will have an on-demand recirculating pump so that we won't waste all that water waiting for the cold water to drain out of 60+ feet of water line.)

Other energy efficiency measures we have worked into our plans:
  • spray foam insulation (as I've written about previously)
  • high efficiency air conditioning equipment within the "thermal envelope" of the house -- because the spray foam goes on the underside of the roof, instead of at the bottom of the attic space, the attic will stay cool and the air conditioning equipment won't have to work as hard because it won't be trying to route cold air through an oven
  • standing-seam metal roof (which reflects heat, also helping to keep the attic cool, and also provides a great surface on which to mount the solar panels)
  • highly efficient windows that will help to keep heat out
  • wide eaves/overhangs, large porches, and an "awning" roof over one large, south-facing window (all of which will keep the summer sun off of the windows)
  • solar tubes in the kitchen (like skylights, but much more energy efficient)
  • high windows to bring light into certain rooms without letting in much heat (referred to in the biz as "daylighting")
  • toilets from the EPA's "Water Sense" list
  • Energy Star appliances (of course)
I'm sure there are more I'm forgetting, but I'm sure I'll write more about them as they are built/installed.

All of the builders we are considering have done green houses, and at least two of them have participated in the city's star rating system. One of them is even currently working with the city on updates to the energy code for construction. An interesting thing about all of this green stuff is that what is considered "green building" today will someday -- probably sooner than you think -- be just "building" as the codes catch up to the best practices that are currently considered cutting edge but also just make plain sense.

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