Last Updated: Jun 15, 2021
One of the essential aspects of sustainability in any home is related to the issue of energy efficiency. The Energy Information Administration of the United States government has stated that residential carbon dioxide emissions have been steadily growing at around 1% each year. This is true despite the significant advances in increasing the energy efficiency of household appliances, lighting, and other domestic devices.
While switching out your old light bulbs for LEDs is certainly a good start, over 50% of all household energy consumption is related to your home's heating and cooling. To make true strides towards a more sustainable and environmentally-friendly home, we need to find ways to lessen the energetic expense of heating and cooling our homes. One of the absolute best ways to heat your home sustainably is by taking advantage of the sun's energy. And - we're not just talking about filling your roof with solar panels to power your heater.
If you have ever found yourself sitting by a large window on a cold but sunny winter day, you have already understood the basics of passive solar design. We can implement certain design elements that incorporate the natural world's rhythms and patterns. In doing this, we can essentially let the power, heat, and light of the sun warm our homes naturally, even when the temperature outside is below freezing.
Passive Solar Design rests on these main principles:
In the northern hemisphere, you want your house to face southward. During the winter months, the sun crosses the southern part of the sky. By angling your house in that direction, you will maximize the amount of sun your home receives.
To best take advantage of the winter sun, you will want to incorporate large windows on your home's south-facing side (in northern latitudes). Building overhangs over these windows will help keep the sun out of the house when it is high in the air, during summer months, and let the sunshine in, when it is low in the sky, during the cold winter months. At the same time, be sure to insulate heavily on the colder, northern side of your home.
With the right passive solar design that incorporates these three elements, you can significantly reduce the energetic (and monetary) cost of heating your home. You might even be able to eliminate the need to turn on the furnace except during the most frigid cold spells. When designing a new home, look for an architect that is well versed in passive solar design. If you want to incorporate this strategy into your new home design, it is essential to include it in the outset plan.
This home, located outside of Bowling Green, Kentucky, does a great job of incorporating the three essential elements of passive solar design. The dwelling is located in a climate characterized by hot, humid summers and relatively mild winters with the occasional chilly cold spell.
The house is angled towards the south with several large windows that receive large amounts of sunlight. Several large trees in the front yard block the harsh summer sun (when the trees are in full leaf), just like the overhangs mentioned above. Like the overhangs again, these same trees let the sunlight enter into the home during the winter months when they are bare and when the sun is lower on the southern horizon.
Finally, the home has a large stone mantle, which serves as a thermal mass to draw in and store the sun's heat. The mantle acts as a slow-release "heater" of the accumulated heat captured during the day.
Integrating a variety of passive solar design elements into your home is a great way to lessen your residential carbon footprint. At the same time, you will also be saving significant money on the energy cost of heating your home.
Tobias runs an agroecology farm and a natural building collective in the mountains of El Salvador. He specializes in earthen construction methods and uses permaculture design methods to integrate structures into the sustainability of the landscape.