A first-person account of building a solar-heated, earth-sheltered house.
The control of nature is a phrase
conceived in arrogance, born of the Neanderthal age of biology and
philosophy when it was supposed that Nature exists for the
convenience of man.
~ Rachel Carson, Silent Spring, 1962
It’s nearly 40 years since I first read Silent Spring, but I think Rachel Carson would be pleased that my wife, Mary, and I are finally here in the country trying to fit into nature, not control it.
As I write this, on February 10, 2001, I’m looking across the Hockley Valley toward the Niagara Escarpment. The sun is still strong and high at 4:30 p.m. Outside, the temperature is –8° C. Inside our sustainable house, it is 14° C. Slightly cool perhaps, but what’s remarkable is that Mary and I have just arrived home after four days absence. While we were away, the only warmth generated in the house came from the winter sun.
How did the house stay warm?
First of all, our house is built into the hillside, not on top of it, and the hillside keeps us warm. Below the frost line, the year-round temperature is approximately 10° C. We tapped this free heat by positioning the north and east sides of our house, to the top of the second floor, below ground. Our ground floor sits on grade. There’s no basement.
The sun is our free furnace, thanks to 174 square feet of R8 ‘heat mirror’ windows on the south and west sides, and building materials that form a huge thermal mass or ‘heat sink’. The sun’s short rays heat up our interior brick walls and tile floor, while the filter in the windows keeps the heat from escaping through the glass.
For our first three winters here, whenever we were away, we recorded the interior temperatures during our absence using a hydrothermograph. In the coldest weather, with the house unoccupied for up to a week, the inside temperature never fell below 10° C.
Of course, on our arrival home, we do have to bring the temperature up to a comfortable level. We do that with our wood-fired Scandinavian-style masonry heater. Its seven tons of fire-brick and cement are slow to heat up, but once they’re hot, they will radiate heat throughout the house for 24 hours.
Our second-floor master bedroom also benefits from the hot exhaust pipes that run through the drying closet. The thermal mass of our airtight house means that it keeps an exceptionally comfortable and even temperature. As a bonus, the earth sheltering helps keep the house cool in summer.
Fresh air in the winter is supplied by a ventilation system — which also gives us natural cooling in summer. We placed the fresh air intake behind the house. On its way into the house, the air travels for 37 feet through that constant underground 10° C, warming it up in winter and cooling it down in summer. No expensive equipment is needed — just two 25-watt fans run by our solar electric system, using no more power than a bedside light.
Our electric system looks like that in any other house: 120 volt AC outlets, wired into a circuit breaker panel, and a 240-volt submersible well pump. On this moderately windy late afternoon in February, our 33-amp wind generator is producing about a third of its potential charge for our eight golf cart batteries. The solar photo-voltaic panels (like the ones used in space) are producing six amps. But the seven solar P.V. panels above our roof can produce as much as 35 amps when the sun is higher and stronger from spring to fall.
In the event that there is no wind and no sun, the gasoline-powered generator (which we used to help build the house) can be started up to boost the batteries. However, this past winter, we used only 50 litres of gas for that purpose.
“I went to the wood because I wished to live deliberately.”
~ Henry David Thoreau, Walden, 1854
If “wood” were replaced by “hills”, Thoreau’s goal is one to which many of us in this region still aspire a century and a half later. Thoreau said he wanted to “front the essential facts of life”. Unfortunately, for many of us, the obligations and expenses of work and family tend to overwhelm the opportunities to pursue a philosophy or realize our dreams. Happily, in 1996, after early retirements, Mary and I, along with our three children, had the opportunity to help design and build a sustainable house.
The project was not inexpensive and there were many obstacles and challenges, although our local tradespeople were wonderful. Building a house that will last for generations takes a lot more time than putting up a pre-fabricated house. Fortunately, we were able to spend two years coaxing our project along step by step. We commuted from our house in the city and boarded with friends nearby — all the time watching much larger houses sprout around us in a matter on months! We watched some of those houses sell for $225,000 — approximately what it cost us for a much smaller, 1,600-square-foot home in which we did a lot of work ourselves.
On the other hand, our ongoing costs are relatively low. Because we’re not on the electrical grid and we don’t use propane, oil or gas for heating, we have never had a utility bill. There is quite a lot of hardwood on our four-acre lot, but we have bought firewood for our wood-fired masonry heater and cook-stove. The cost of wood could reach about $500, if we were heating non-stop through a long cold winter.
Heating with wood also requires a little education about which are the best woods to use, when they’re ready to burn, and how to avoid creosote problems. Carrying firewood may seem a bothersome chore, but we found that a plastic toboggan loaded in the woodshed glides over the snow with little effort, right through the front door to where we need it. As our pioneering ancestors used to say, wood warms you three times: first when you split it, then when you carry it into the house, and finally when you burn it.
The ongoing maintenance of our sustainable house might not be everyone’s cup of tea, but Mary and I enjoy it. We are both well accustomed to composting food waste, using composting toilets, and being able to boil water on our wood stove in less than ten minutes.
We are also very pleased with our solar hot-water system and grey water purification. All the waste water from our sinks and shower passes through and irrigates our indoor garden — and gets purified by the plants’ roots before going into our wetland.
Many people have told us that they too would love to build a sustainable house, and many are doing so. More than simply reducing expenses, the motivation appears to arise from a genuine desire to reduce the “sustainability gap”.
There is a growing understanding that our lifestyles in the West are possible only because the majority of humanity consumes so little. In fact, as people are learning, we would need about four more planets like earth to enable all six billion on this planet to live the way we do in North America.
Alas, there are no new territories let alone planets to which humans can emigrate. We simply have to reduce our consumption of resources and live more simply. We humans don’t need to melt the ice caps, deplete the ozone layer, or allow urban sprawl and new provincial super-highways to cover our precious fertile farmland and forests. Although many of our city-dwelling friends and politicians may not understand the urgency of conservation, we can teach them. As Ulysses says in Tennyson’s famous poem, “’Tis not too late to seek a newer world.”
Give away your hair dryer and toaster! They use between 1,000 and 1,500 watts each and will run down your electrical supply. However, our 12-cubic-foot SunFrost refrigerator uses only 55 watts and compact fluorescent lights use between 7 and 17 watts. Generally, one has to avoid electrical gadgets, conserve and keep an eye on the battery levels.
Saving non-renewable heating fuels—and $$
Imagine a balloon surrounding your house in winter. Puncture it with one tiny pinhole and out goes your heat or cooling in summer. Most of our houses have heating leaks the equivalent of an open window. To find your leaks, pick a cold windy day and use a smoke pencil (or a smoking incense stick or candle) along cracks, joins, windows, doors, fans and fireplace flues to locate the drafts. In summer, it’s more effective to place a powerful fan in your main door (sealing the space around it) in order to exhaust the air from the house and show you where the leaks are coming in from outside.
In North America, we waste nearly half of all the energy we use to heat and cool our houses. It pays to get good insulation and seal every crack, including electrical outlets. Windows can be a big source of heat loss; our ‘heat -mirror’ windows are rated R8 and our insulation is R40. The warm insides of our walls have a vapour barrier, but the outside cladding allows air to migrate. Our south and west foundations are only two feet deep because we insulated underground to prevent the frost from penetrating.
Composting, grey water, plants
We use the Clivus Multrum system of composting toilets and grey water purification through an indoor garden. Outside, we’ve landscaped with plants that thrive in drier conditions, so we rarely have to water. Our low sheep’s fescue grass does not require fertilizers, pesticides, or even mowing.
Recycled and natural materials
We tried to examine the life cycle of the products we used. Many products such as weeping tiles use chlorine (a threat to the ozone layer) and plywood emits formaldehyde gas. Much of the interior trim was made from recycled wood and our kitchen counter tops consist of natural, inexpensive floor tiles. The interior side of the walls have a vapour barrier, but the outside is stucco which allows the air to migrate.