Sunshine on my double-glazed low-E windows makes me happy
Posted by Daniel Hall on February 15, 2008
Economist.com’s Tech.view columnist has a great article up today about his research into putting solar cells on his own home. The article provides an accessible overview of photovoltaic technology as the author goes through the calculations of home installation. His conclusion? Even living in sunny southern California, he estimates that going solar would cost him “$600 a month for ten years, even after setting the interest charges against tax. And all that just to feel good about saving $75 of electricity a month.”
Although the article doesn’t state it explicitly, it sounds as if the downfall of solar technology is not only the expense — around $65,000 at his home, before any subsidies or rebates — but that there are easier ways to go green. We get a clue here, as he talks about the electricity needs of his home:
It’s not even as though the place gobbles electricity. When the house was being rebuilt five years ago, the new roof came with over a foot of thermal insulation. The floor-to-ceiling windows along two sides of the structure were replaced with double-glazed “low-E” glass (the sort that blocks infra-red radiation), and thermal linings were included in all the exterior walls. Even during the summer, the air conditioner usually stays off.
Admittedly, the architect went overboard on lighting. Fully illuminated, the house demanded seven kilowatts of raw lighting-power before fluorescent lights replaced thirsty tungsten filaments. Overall electricity consumption is now a reasonable 8,300 kilowatt-hours (kWh) a year.
Based on this description it sounds like his home is already pretty efficient. And those efficiency improvements were probably undertaken primarily because they made financial sense — the installation cost was less than the expected savings on energy. But given the author’s interest in going solar and his exactitude in calculating the cost, it’s also likely that he’s much more environmentally aware and economically savvy than your average homeowner. There’s a lot of research suggesting that many other — less savvy — property owners are leaving money on the table by failing to increase the efficiency of their buildings.
From the viewpoint of both the homeowner and the electricity company, efficiency improvements and solar technology look very similar: they reduce a home’s demand for electricity from the grid. Given the large subsidies regulators seem ready to give out to solar panels — perhaps $14,000 in this author’s case — it’s easy to think that regulators could be getting a much better deal if they figured out how to buy some energy efficiency with those dollars.