Tuesday, February 22, 2011

A passive solar bermhouse

We live in a passive solar berm house. It was built as an off-grid home in the 70's during a time when back- to-the land-homesteaders inhabited the back roads and hollows of Maine. Driving around in the more remote parts of the state we have found many alternatively built homes from that time. We feel fortunate to live in one ourselves.

Because of the oil shocks of the 70's, building for energy efficiency was a serious consideration and this can be seen in our homes construction. Because it is a passive solar home the first thing to notice is that the house is south facing. We have some windows on the east side and one small window on the west side. As the sun passes over our dome during the day the sun shines in our windows most of the day. The over hangs from the roof provide some shade from the sun during the summer when the sun is higher in the sky. But I am, also, working on shades and room darkening curtains in order to keep the sun out during the height of the summer day. During the winter, when the sun is lower in the sky it shines right in the house, warming the house nicely. Most winter mornings we have been able to shut down the wood stove and rely on a slow burn from the stove and the sun to keep us warm during the day. This really cuts down on the amount of wood we have to use.

A second feature of a passive solar home is its ability absorb heat. We have concrete floors, a stone hearth, a concrete wall in Evan's room and the brick chimney in our bedroom. These features absorb heat during the day from the sun, the heat generated from our woodstove and other heat generating appliances like our fridge, cook stove and freezer. At night the collected heat is slowly released.

The final feature of our home is the berm. This is hill of dirt that is built up around the east, north and west sides of the house up to the top of the first floor. It insulates the north side of the house, which is the coldest side of the house. It cools the house in the summer and helps to maintain a constant temperature. Our cold room is located in the berm and keeps pretty cool in there.

The windows that are on the east, north and west have homemade shutters. These shutters have a thick layer of insulation in them and we keep these closed during the winter. The rooms are small and efficient to heat. The door at the top of our stairs is also insulated. When we need to get the house warm we close this door and only heat the down stairs

Because the house is over 30 years old there are some updates we need to take care of soon. The doors into the home are handmade with a thick layer of insulation between some fancy wood work. But you can see light . We have tried weather stripping around them for this winter but we have noticed that is has started to wear away with use. So it would be best to replace them. Our windows are double paned but original to the home and are foggy. We have grander plans to extend the foot print of the second floor to the full size of the first floor. But in order to maintain the integrity of the passive solar design we will find an architect to help us with this. Finally we need to work on some ventilation for the cold room so that it is a room we can use for 4 seasons. Because it is basically underground, condensation creates problems in the summer when temperatures swing from warmer day to cooler night. Eventually we would like to tile the concrete floor on the first floor but for now this is not a priority.

Living in a home like this has been a lesson in not only how one lives in a house but how one uses a house to its maximum efficiency. Our house was originally built as an off-grid home. The person we purchased it from had power put in it 2o years ago. One day we hope to return the home to off-grid but before we do that we should learn to not need as much energy as we use. Learning to use our home in the manner for which it was designed is one step in this process.


Wendy said...

So awesome!

We're hoping to do some renovations that would help us make better use of solar energy for heating, for cooking, and, perhaps, electricity generation, but like you, we need to cut our usage to the bare-bones before we attempt to install power generation equipment.

Being off-grid is my dream, too. I'd love to be one of the first 'off-grid' suburban homesteaders ;).

Robj98168 said...

You can get heat absorbing clay tiles for your concrete floor. Very cool design y'all