Tiny Cottage in the Sun
We haven’t had a fire in the woodstove for the last two days. Not that it has been warm outdoors – Quite the contrary. The temperatures have been about -11°F at night and only raising to the low teens in the day. But it has been Sun-days and we’ve been warm in the cottage.
Passive solar heat warms our house wonderfully even though we don’t have the best of exposure angles. The same thing happens in the animal hoop houses although they have the added advantage of warm toes from their composting bedding – something I’ll not do directly in the cottage!
Due to our location on the mountain we fast a bit east of south rather than the west of south that would be better for our climate. This gives us the morning sun that warms us early. There are other locations on our land that would have given more sun but the trade off would have been a lot more wind – a major thief of heat across windows.
Many passive solar houses experience overheating on sunny days. For this reason it is recommended to limit the amount of windows on the south of a building. (Perhaps I should say sunny side for those in Australia and other places south of the equator.) We have far more glazed area than recommended for our floor square footage yet we don’t over heat. Why? On sunny days the incoming solar radiation is soaked up by the cottage’s 100,000 lbs of thermal mass. Then the warmth is slowly released from the masonry and back to us over a period of days. As the sun gets lower in the sky during the winter it reaches further back until it kisses our back wall. Then with spring it retreats to the front windowsills to keep us cool in the summer.
The cottage is able to actually stay above freezing all winter without any inhabitants. We found this out the first year before we moved in. That was when it had been freshly built in the early winter and hadn’t even had the benefit of summer time warm up and pane glass windows.
The solar gain is part of how we only burn less about 3/4 cord of wood a winter despite the fact that our roof still only has minimal insulation as demonstrated by the ice dam. Someday we’ll berm the roof and at that time we’ll also add a bit more insulation. We also plan to make super-windows like I made down in the old farm house. I must admit that I was surprised that so little insulation, just two sheets of foil-bubble-bubble-foil, is sufficient to keep us so warm. Of course, most of the time we also have quite a snow load up there which insulates us like an igloo.
The above mentioned ice dams are actually rather useful. They keep the snow on the roof rather than letting it slide off the arch. This gives us more insulation and protection from the wind. I purposefully had made lips at the edge of the roof to retain the snow but the ice further improved on my plan. The final roof will gull wing out even further to enhance this effect.
Outdoors: 70°F/60°F Sunny
Tiny Cottage: 11°F/-11°F
Daily Spark: I declared, “I’m innocent. Innocent as the driven snow.” To this my son quipped, “Yes, and blizzards kill a lot of people every year!” Too true.