It was a comfortable 66 degrees in our house at 3 p.m. Friday, even though it was 12 outside. I had put the last piece of wood in the stove at 8 a.m., and the oil furnace had not gone on.
Unlike solar hot water, which we have, or solar electricity, which we don’t have, direct-gain passive solar heat is cheap and simple to install. It doesn’t involve any pipes, wires or complex systems. When we renovated our house in 1998, we installed south-facing windows in the living room. That was a standard improvement that provided a view as well as some heat.
Our builder and friend, Bick Corsa, left, suggested we install a thermal air panel, which I had never heard of before. This is a 3-by-5-foot horizontal wooden box containing a piece of tempered glass over a piece of black-painted metal roofing (shown above in summer). The sun shines through the glass onto the metal, heating the air, which rises and comes into our living room through a vent at the top. There are inlet vents bringing cooler inside air back into the box from down near the floor, setting up a circular flow as heat rises. Bick put a panel on our second floor as well (shown between the windows above). You can put your hand over the vents and feel the warm air.
Bringing the sun into our heating mix saves us a lot of money. We burn two cords of wood per winter, half of which I cut myself and half of which I buy unseasoned and then age for a year or two. We consume about 130 gallons of heating oil a year, with the furnace going on mainly while we’re sleeping. We have electric heat for our tenants upstairs as a backup, but they seldom need it.
In her book “This Changes Everything,” Naomi Klein writes of visiting a Cheyenne reservation where teams of people were installing “solar boxes” on the sides of buildings. Renewable energy “demands that we adapt ourselves to the rhythms of natural systems, as opposed to bending those systems to our will with brute-force engineering,” she writes. “We need to unlearn the myth that we are masters of nature and embrace the fact that we are in relationship with the rest of the natural world.”
I’m always aware in winter of whether the sun is shining, because that determines whether I’ll keep the wood stove going all day. On cloudy days like Saturday, I’ll keep the shades over the windows all day and keep the stove pumping out the heat.
Bick Corsa, who lives in Northampton, has come a long way from the rudimentary solar panels he installed for us 17 years ago. In 2010 he won a $10,000 state prize for a solar house he designed and built in Turners Falls. It has 1,152 square feet, sold for $180,000, and generates up to two times as much energy as it uses.