In our household we like hot showers—or at least one of us does. The other one prefers a more temperate cascade but tends to dally under it. In the old days—which ended two years ago when we installed a solar hot water system—the duration of his shower, or the temperature of hers, could spark a “discussion.” Now we mostly talk about how we’ve become our own, privately held utility, producing every drop of hot water we use in the summer from the two solar panels perched on our roof. (We also have an array of photovoltaic cells up there that makes much of our electricity, but that’s another story, for a different day.)

In the winter, when the sun shines less and the ambient temperature here in the Green Mountains of Vermont often dips below freezing, we still make about half the hot water we use, an amount that increases by half again the rest of the year. These days, when the rising cost of heating oil and natural gas and electricity makes the news, we reflexively do the math: not of how much money will be going down the drain in the coming year, but of how much energy—which is to say how much money—we’ll be saving by using the sun to heat our water. Last year, when energy prices were significantly lower than they are now, we spent hundreds of dollars less in the shower than we would have by using conventional fuel. This year that number is bound to go higher. We expect that our $8,000 solar hot water system—which would have been considerably cheaper if we lived in a place where winter wasn’t five months long—will have paid for itself five years from now.

Solar hot water relies on rather simple technology: a couple of big glass panels installed on a south-facing roof, with a dark absorbent material sandwiched in between and liquid running through it. The dark panels absorb the sun’s heat, which is transferred to the liquid, which is then piped down to a holding tank. “It works on pretty much the same principle as the one that makes the inside of your car heat up on a sunny day,” Dori Wolfe, co-owner of Global Resource Options, told us one day last fall when she stopped by to give us a “tour” of our system.

Our tank is in the basement, a few feet from the boiler. On a good day the water in there is so hot—about 180 degrees—that the boiler never turns on. Even a partly sunny day is money in the bank, since the panels preheat the water well above the 55 degrees at which it comes out of the ground, giving the boiler a 40-to-60-degree—or more—head start. U.S. solar hot water got a bit of a bad reputation after the energy crisis years of the 1970s, when, spurred by a massive federal tax credit, a large number of contractors jumped into the solar business. Hard as it may be to believe, some of these contractors were in it for the money, and when the federal subsidies dried up, many got out of the field, leaving people with orphan systems. In the past few years, though, solar hot water systems have been making a steady comeback. Even before energy prices began their recent spike, many states, worried about the cost of building new power plants or trying to cut greenhouse gas emissions, were willing to subsidize part of the cost. And now the federal government is chipping in, offering up to a $2,000 tax credit to anyone who is willing to take the solar water plunge.

There are other ways to reduce domestic hot water costs, and before Wolfe and her colleagues spent a day climbing around our roof and dropping pipes into our basement, we pursued them. We made sure our faucets had flow restrictors, that our washer was a front-loading water miser, that our dishwasher had the highest energy star rating. We were conscientious about how often we did the laundry, and of how full the dishwasher had to be before we pushed “start.” And then we hit a wall. We had reduced consumption, yet we were still living high off the energy hog. The only way to set it free, we realized, was to capture the warmth of the sun.

To be honest, the one of us who likes extreme showering was skeptical that a couple of pieces of glass mounted on the living room roof were going to provide sufficient heat. (If the one who dallies had his own concerns about being rudely interrupted by a downpour of frigid water when the solar stream ran out, he kept them to himself.) But we went ahead anyway, reassured by Wolfe’s facts and figures, and spurred by a desire to make our household as pleasantly energy efficient as we could. It’s two cold winters later and we’ve never run out of hot water. Not once. We’ve operated the dishwasher and the washing machine and the shower simultaneously and have never been brought up short.

We’ve run the dishwater, the washing machine, and two showers and have had hot water to spare. We’ve run the dishwasher, the washing machine, two showers, and the hot tub—no problem. Okay, the hot tub is wood-fired, but you get the point. We have never not had hot water when we needed it. Which brings up an interesting point. Environmentalists sometimes worry that a new supply of low-cost power from the roof will simply encourage homeowners to use more energy. Why not a four-hour shower? Why not a washer for whites and one for colors? But if our experience is any indication, solar power has just the opposite effect.

Suddenly energy goes from something abstract to something homegrown. It’s like canned tomatoes from the store or ripe beefsteaks from your own garden. When the fuel bill comes every month we hold it up with pride. We did this, we say, with a nod to the sun.

Sue Halpern’s most recent book is Introducing Sascha Abramowitz. Bill McKibben’s is Wandering Home.

article source : www.houseandgarden.com