The solar home

For over twenty years now, Dr. Thomas Eastler has been heating his home with the power of the sun.

Technically, he uses passive solar power, which in his words is “collecting light from the sun and allowing it to heat [your home] without any additional input.” As anyone who has ever laid their hand on the dashboard of a car after leaving it in the sun in August can attest, heating with ‘just’ the sun is nothing to laugh about.

Eastler’s house itself is facing to the south, with six-foot high windows to capture as much sun as they can. An open design interior makes sure that the warm air keeps circulating throughout the entire system. When it’s dark or cloudy out, window quilts roll down to cover the glass, allowing the windows to retain heat as well as many stickbuilt walls.

From the top of the ridge, Eastler, who ran an active cattle farm for twenty four years, has a view of fields that have been used for herd grazing for more than two hundred years. Beyond that, the river valley as it runs to mountains in the distance comes as a bonus to his high-efficiency home. The house is wired for electricity, but that’s only used for heating water – laundry and showers, for example. The only active heating system for Eastler’s house is a seven-hundred pound soapstone woodstove. He goes through two cords of wood in a typical year. This winter, which Eastler says has been a bad one, may bump that usage up to two and a half cords. Converted to fair value for when the wood was bought, he paid about $700 to heat his home this winter. Costs for heating with oil (five hundred gallon tank, filled twice during the winter) can run more than $2,000.

Another facet of passive solar heating doesn’t apply to the open air of the home. With a few dozen feet of black rubberized hose, at simple water heater can be rigged up. The hose is mounted atop a south-facing roof, yielding a roof-full of water that can be more than 120 degrees when it’s decanted. With a big enough roof, there’s certainly enough water there for a quick shower. This could be a passive solar setup – with no active mechanical component – but more likely it would be active solar, utilizing pumps to move cold water into the heat-collection zone on top of the roof and move the warm water down into an insulated reservoir. According to Eastler, if he had installed such a system when he renovated his house in the 1970s, he would have saved himself thousands of dollars, with the system paying for itself in a few years.

Looking at the small greenhouse that Eastler has attached to his home – heated to a comfortable 50 degrees, on a day where the high has been less than 10 – one can see striations in the wood; a characteristic of heat damage. This room gets hot enough in the summer to scorch.

There are a variety of ways to increase the amount of sunlight entering your home. Designing it correctly helps, obviously. If your home is built along an east-west axis, then larger windows in the south side of the house will let more sunlight in: in the northern hemisphere, the sun will spend most of the year in the southern latitudes, so more southern exposure means more sun. Also, smaller windows and more insulation on the north side of the house means that the Nor’easters coming down out of Canada and the Atlantic are battering themselves out against a solid wall.

Many of the farmhouses around New England are a testament to this strategy. Often, they’re built on the east-west axis. Heating with wood, our ancestors knew what they were about. When you had to cut all the wood you needed for a winter, you did your best to minimize it.

An important feature of a good passive solar home is the window setup. Cheap windows may be tempting, but spending the extra cash to get high-quality windows is worth it. Buying the right kind of windows: low-emissivity, high solar gain, allows more energy to get through – as much as eighty percent. Once the sun has gone down, insulated curtains with a high heat-retention value are lowered to help prevent heat going out. Windows similar to the ones that Eastler uses were first developed in places near to the equator, in cities that were more concerned with keeping the sun out than keeping it in. The idea was to make a film that would bounce the heat from the sun out, while letting the light from the sun in. These windows are basically the same thing – just backwards. They have a coating on the glass that allows infrared radiation in from the outside, but not out from the inside.

In the winter, the solar input can be greater, Eastler says, because the snow on the ground reflects light. Thus, when the direct sunlight hits the windows or the southern wall of the house, it gets let in or absorbed, and when that light hits the snow, it gets bounced into the walls or windows, effectively allowing half again or double the amount of energy into the house. In a New England winter, on average, there are more clear days than there are cloudy ones.

The house is hooked up to the electrical grid, and electricity is easily its biggest expense. Future improvements, Eastler says, could include the installation of photovoltaic solar cells (the ubiquitous solar panels) or wind power.