14 May 2012

Adventures in Home Energy Ratings

After writing last week about the various home performance rating methods out there, I came across an old newspaper article about the Microsoft-Hohm home energy rating website.  It seemed like a cool system and a good way to get home performance feedback without spending a lot on an energy audit or HERS rating, so I decided to give it a try.

Microsoft-Hohm rates houses on a scale of 1 to 100, with 100 being maximum efficiency. So I wasn't surprised to find, when I looked up my address and found the old 1960s house information, that it was rated a 52.

Unfortunately, when I arrived at the website, I also learned that it's being shut down at the end of the month due to low participation. But the bigger disappointment was when I updated my house information from the previous house and found that all of our improvements were only worth three points.

Still barely better than average.  (And even after telling it that we have virtually no utility expenses, it still insists that our annual utility expenses total nearly $3,000.)

This is partly because there was no way to tell it about our geothermal system, solar panels, or other green upgrades. When I selected "electric" for our HVAC, the score went down (only as efficient as the original house), so I changed it to "gas" and earned back a few points, but there was no option for "geothermal."  (There's a section that lists suggestions for improving the energy-efficiency of your house, which lists things like low-E wood windows, but no way to tell it that we already have those.)

The website is set up to automatically access utility information, but it doesn't seem like many, if any, utilities signed on, so I could only manually enter my utility info. But even entering electric usage of zero and gas usage of 1 unit per month didn't change its assumptions about our annual utility use. Frustrating.

I don't know if Microsoft is going to make another attempt at a home energy rating system, but if they do, I certainly hope they will take a broader view of possible building materials, techniques, and green upgrades. But if you have a more traditional home and want to see how it rates on this system, hurry over before the end of the month and check it out.

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