What Is the Solar Potential of Your Home?
- Posted by: Zach Frechette
- on December 29, 2008 at 6:43 pm
A popular story in The New York Times this week documents the rising trend of “passive houses“—homes that are built without furnaces and instead are constructed to retain heat generated by the sun, appliances, and the occupants themselves. They’re slightly more costly to build, but the savings—both financial and environmental—are pretty staggering.
It’s an exciting trend, to be sure, but not everyone is in the market to build a new house. So what can you do to your existing abode? One answer is to add solar panels. Historically, this has been an intimidating prospect, mainly because of the high cost associated with installation. But a new site, RoofRay, let’s you estimate how much power you could potentially generate from the sun, and how much it could save you each year. You input your address, then use RoofRay’s tools to map out the shape of your roof. In addition to estimating annual savings, the site lets you compare various different installation options and chart your return on investment. At worst it’s a fun awareness tool—I, for example, feel great about my 8.97 watts-per-square-foot potential—but at its best, it’s a way to understand the options available to you when purchasing a new house, or renovating your current one.
DISCUSSION: 3 Comments
Thanks zach. Roof Ray is really cool. It looks like I could get a peak power output of 26,000 watts DC which would more than offset my power usage, and put me as much as $1700 in the black on my power bill. (Thanks to a large flat, downtown LA roof.)
How does that work? Can you actually sell your power back to the power company? How fun would it be to see your power bill became an invoice.
Either way, if their calculations are at all accurate, it’s really compelling to look into solar panels.
There’s also a start-up in Berkeley called Sungevity that does something similar on their website. And they provide quotes.Casey – 26kW !!! You must have something like a 4,000 sq.ft. roof ! In any case, you will unfortunately not see bills become invoices under the current rules. But for instance you can still be given a credit for your excess production in the summer months that LADWP will apply against your winter usage when the production from your solar system falls short from covering your flat’s electrical needs. They won’t cut you a check.
In addition, they probably won’t let you install too big of a system anyway: there’s a formula under the California Solar Initiative (PG&E, SDG&E, SCE) for maximum size and I expect LADWP to have something similar. And finally you’ll be happy to have a <10kW system from a process standpoint, larger systems have a more complicated process to go through…
Thanks Raph. That’s helpful stuff.