A Cleantech Blogger's Home Energy Audit - The Results Are In
Posted Oct 11 2010 10:01am
A few weeks ago I blogged a very bad experience trying to get an energy audit done on my home. The vendor, Standard Renewable Energy , part of Gridpoint , just didn't do the job. After our blog article, the company came back to do the audit right for me, complete with a IR camera looking for hotspots, blower door test, and duct test.
I just got my report, and wanted to share the experience. Consider it kind of like our cleantech blogger CSR report. I've posted the full energy audit report on our Cleantech.org Yahoo! Group for your reading pleasure.
For those of you who want to blog your own home energy audit, I'd love for you to join the Cleantech.org Yahoo! Group and send in a message with your experience or report in attachment.
If you're looking to sort through what kinds of products are available, our sister site www.greenhome.com/ has a ton of them including
The results were mixed, not bad over all, but a lot of room for improvement.
I apparently have a pretty low energy rate house, at 23 kBTUs/Sq Ft, apparently a little over half the average . Not bad for a 55 year old ranch house. This despite very little insulation in the attic, none in walls, and not particularly efficient appliances. But for better or worse, with our total summer energy bill in the $125/month range ($8.9/kwh) plus gas bill for hot water at less than $20/month, not much makes economic sense to do. I think we may just be very boring in our energy use!
We didn't do so hot on the blower and duct tests (that's where they pull a light vacuum and measure how leaky your house envelope and duct work is. The combination is a measure of how much your system is air conditioning things other than your home). We are about double the recommended levels of leakage, and that's after redoing the windows.
And we haven't insulated the attic (current R value is estimated at 13, something like R 38 is desirable). The nearly $1800 attic insulation quote I had gotten previously was looking like a 5-7 year payback, and unfortunately paying to seal the ducts and replace the air return looks like it would be marginal as well. Sealing the ducts probably would pay off, however, we have an old house whose air return is way undersized and very poorly sealed, probably a vestige of the original heat only return pre air conditioning, meaning I'd need to tear up my hallway and put a new one in the ceiling to do it right. The other big move would be to do some sort of an attic fan to do active attic ventilation , and keep my cooling load down.
One bathroom is basically an energy black hole, sucking my energy straight out to somewhere, but except for attic insulation they didn't have a lot of good suggestions for this one. Since it's my bathroom not hers, my wife just didn't seem as concerned as I was.
The big contributor to be honest is likely not even in the house - we bought a very well shaded moderately sized house with 4 huge oak trees and 1 magnolia shading it, and keep the AC in high 70s in favor of a lot of ceiling fans.
And apparently, despite having big pretty windows and lots of light, we don't have a high window area/square foot ratio, and all but one are pretty shaded. We did replace them with energy efficient double paned windows this summer, which besides an Energy Star washer/dryer was our only major energy efficiency move so far. Even more than the energy, replacing the windows made a huge difference in comfort, while still keeping the AC temperature fairly high.
On the negative side, I added 26 recessed can lights to the ceiling (I can't help it, I like light!), about doubling the lighting capacity of the house to 5kW with very few CFLs . But each room has multiple lighting systems (eg, ceiling fixture plus recessed or recessed plus lamps) on different switches, and we are pretty good about keeping on only what we need, so it really didn't drive up the usage.
We've got a couple of small, cheap items that definitely make economic sense . Only 1 of the 4 outside doors is weatherstripped (and one has a huge south facing single paned window that failed the IR test badly), and caulking along the base boards/sealing the various light switches (they make basically soft gaskets you can put on yourself that do the trick) and attic stairs would help seal the living area a bit (maybe just offsetting all those lighting cans!).
The south facing roof is mostly shaded by trees, and that plus our low electricity and hot water usage and low electric rates means solar is pretty much out.
The one thing I was really excited about which the auditor just didn't seem to think was worthwhile was an attic radiant barrier. They recommended simply attic better ventilation as a first step.
In any case I'll blog the results in a couple of months and give the blow by blow on whatever we end up doing.
It's hard to really find a lot things that were economic and environmental no brainers. Most of the big items looked to be "on the bubble." Lots of little things from CFLs to those little light socket gaskets and weatherstripping need to get done. And I do need to bite the bullet on some big items like the insulation.
Part of me really wants to see how far down I could get my energy usage. Is 300 kWh/month possible without self generating? I'm going to have to do some calculations.
One of the problems with a house like ours is that when you start with moderately low usage, and plan on doing all the small cheap items, your bill gets so low you can't payback any of the big ones. So maybe energy efficiency retrofits is only really the province of the true energy hog or those who just believe.
Neal Dikeman is a partner at cleantech merchant bank Jane Capital Partners LLC , chief blogger of CleantechBlog.com , and is responsible for starting companies in carbon, superconductors, solar and fuel cells, as well as launching Cleantech.org . He is a Texas Aggie, and his grandfather and great grandfather were both refrigeration and air conditioning engineers.