Free Heat Forever!
Posted on June 1, 2008
Filed Under Eco-Tips |
Free heat for your home forever. Sounds too good to be true.
Maybe not.
By using passive solar design principles, you can heat your home using the sun as your heat source and your home as the solar collector and radiator.
With passive solar heat, you can create a comfortable, warm, and beautiful space that corresponds with the environment. Passive solar heating along with a well insulated home can cut down your heating costs by as much as 75%, and on many days eliminate heating costs altogether.
4 Design Principles
There are four important basic design principles to start taking advantage of the sun’s free heat:
- South facing glass
- Thermal mass
- Heat distribution
- Building insulation
South Facing Glass:
The orientation of your house relative to the sun is the first step in taking advantage of the sun’s free heating. You should face the long side of your house towards geographic south. This south side should contain anywhere from 60-85% windows (glazing). The amount and location of glazing is determined by wall size, how much sun reaches the house, how much heat gain you need and any natural sun blockage that may exist.
Thermal Mass:
To avoid large temperature swings and to keep temperatures consistent, the glazing should be supported by integrated thermal masses within the house. Sunlight entering through the glazing is absorbed by the thermal mass which creates a “heat sink” that absorbs heat during the day and radiates heat into the home long after the sun has gone down. The thermal mass could be a concrete floor, masonry wood burner, adobe fireplace surround or even water placed in an appropriate area of the home. It is an appropriate material suited to your home design. The size of your heat sink is determined by the volume of air you intend to heat and the amount of cooling of that air that takes place through the shell of the house.
Heat Distribution:
Also important to passive solar design is heat distribution throughout the house. Natural convection, the process by which air rises or sinks because of differences in temperature, will distribute the heat throughout the cooler areas of the house. Designs to facilitate this natural airflow allow for various venting schemes such as window placements near the floor and the ceiling.
Insulation:
Insulation is the key design principle that keeps all the free heat absorbed within the house. The performance of any passive solar system can be directly related to the attention paid when insulating the walls, floors and ceiling of the house. Performance can also be greatly enhanced by choosing materials with high insulation values and employing moveable insulation to cover south windows during long winter nights.
These basic design principles keep you warm and comfortable for the life of the home and are NOT connected to the continual rise of fossil fuel costs. Your ongoing heating costs remain low or non-existent. Passive solar design should be considered with any new home or remodel.
Geoff Clarke is a local contractor specializing in sustainable home construction and with partner, Carla Zezula, owns Natural Energy Designs, Inc. a consulting firm dedicated to sustainable building.
