Hi Guys,
I Just got my utility bill for the first month of full solar operation. Gas consumption was 0.07 therms / day ($0.29), as compared to a summer monthly average of approximately 0.75 therms/day ($1.40). Why, you might ask, did the cost not go down by 10X like the usage? There’s a flat monthly customer charge of $5.30 for service, which accounted for the bulk of our $8.12 gas bill. As predicted, virtually all the gas we were using in the summer was for heating hot water.
It’s not quite the whole story, since we were away for 10 days on vacation. We probably would have used 0.10 therms/day. But it still looks like we’ll save on average a buck a day, as long as the sun keeps shining.
Other interesting facts: average family usage in the summer in Palo Alto is 30 therms / month. So we started at about 75% of normal usage. Then again, we’re about 75% of the size of the average family. A therm, in case you’re wondering, is 100,000 BTU and will heat 160 gallons of water to approximately 130 degrees. Amazing what you can learn from your utility bill.
The system is working perfectly. Hope you’re installing a bunch of systems. I was walking around midtown Palo Alto and looking at the rows of nearly-identical ranch houses with their unshaded, south-facing, 20 degree asphalt shingle roofs and thinking “That’s a good one…and that one…that one too…” Now I’m obsessed!
See you,
John S.




