Saturday, March 14, 2009

Online resources for green building and green retrofit

Andy Revkin, the NYT's climate change blogger, is asking today for readers to submit online resources for home energy retrofits and green building.

This is what I sent in:

For any readers who are thinking of building new, and who don't believe net-zero carbon is possible in a cold climate, our recent Unity House/Open 2 project, a partnership between Bensonwood timber framing and MIT's Open Prototype initiative, is almost done with it's first winter (in mid-Maine where we still have two feet of snow). This should be a pretty good proof-of-concept for new green building systems in the north.

The idea was to build an relatively affordable modular home that uses passive solar design combined with solar PV and hot water, as well as an innovative two-stage air-to-air heat pump from the Hallowell company of Maine.

The home is now built and in-use, and we'll soon have a full year of power bills, and will be able to see whether it nets out electricity production annually as designed. But I was giving some architects a tour the other day when it was about 15 F and a bitter NE wind. The heat pump wasn't running at all (meaning all the heat was coming from sunshine) and the meter was running backwards at about 4.5KWH. As we gave the tour, the interior temperature warmed two degrees as the sun came higher in the sky, and this was with curtains two-thirds shut on the passive solar windows. We are confident that the home will net out over the course of the year.

This building is now reported all over the Internet. Just google "Unity House," or go to the MIT Open 2 website at

Under the Open Prototype system, the plans are available online for other builders to use.

Other readers will be interested in retrofits that move towards good energy savings and net-zero carbon footprints. My own experience is that for a more traditional dwelling (a Maine Farmhouse), you can get very good results with a program of retrofits taking advantage of the IRS home energy income tax credits, and using the Lawrence Berkeley Lab's Home Energy Saver (HES) to help work out the priority of finances without having to pay for a professional energy audit.

We got our farmhouse's fossil energy use down about 80% using this system. It's a little complicated to use, but a great free resource. It can even help you decide if you need a serious energy audit -- if you start using it and "time-out" because you don't understand it, then you should get a professional. But if you're average at math, and have had a couple of math classes, or been a tradesman, you can probably do 80-90% of what the professional does for free using this software.

The Home Energy Saver is at

The program allows you to save your data (online) and keep coming back year after year (even if you switch computers), to search for new savings or update with new energy prices. So for instance, when propane was cheaper, it wasn't nearly as high a priority for us to switch out our propane hot water system, or add to it, with a new solar thermal system. The HES showed we were better off putting that money into insulation. Since then our consumption on hot water has gone up since we're home more this winter, while the price of bottled propane went up with oil and stayed up for some unknown reason when oil came down. Now it would be more worth the money to add a modest $2,000-$3,000 evacuated tube system, instead of adding insulation.

When I present results like these the irrationality of climate denialism comes right to the front.

If we can get results like this with only a little additional expense, it isn't reasonable to think we even need to go on using fossil fuels for housing heat and power at all, whether we are worried about climate change or not!

1 comment:

Taru said...

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