Sustainable Ramona: Building Principles for New and Existing Homes
Sustainable Ramona is a local non-profit organization dedicated to preserving our surrounding environment. By answering your questions each month, we intend to provide you with common sense, affordable, short- and long-term ways to manage issues like increasing water shortages, high heat, rising electricity bills, and reduce waste going to landfills.
This is the second in a series of three articles examining energy efficient buildings with a focus on residential homes, although the concepts work in any structure. See the first one here.
Construction that has openings in the structure can help with energy efficiency.
The placement of windows can make a big difference in solar gain in the winter. By orienting many of them towards the south, you will be able to capture the sun’s heat in the winter to warm your home with passive solar heating.
In this climate with many hot days, an optimal overhang will shade south-facing windows in the summer while allowing low winter sunlight into your home for passive heating during the shortest days of the year.
Study your construction site carefully and determine where the prevailing winds blow, and visit the site at different times of the day and in different months if possible. Plan your windows for optimal airflow and circulation. Open the windows on cool summer nights and close them when it starts to warm up in the morning.
Use solar screens on the outside of any windows that receive direct sunlight without adequate shade. It can block up to 85% of the sun’s heat before it reaches the outside of the glass.
Of course, use double-glazed or triple-glazed windows if they are affordable. Not only do they resist heat leakage in the summer and cold leakage in the winter, but they also make the house very quiet, despite the difficulty of opening and closing them. Add high, operable windows to vent hot air, in conjunction with vaulted ceilings (hot air rises). Do not use windows with metal frames because they conduct heat.
For exterior wall construction materials, the wood framing should be a minimum of 2×6, in order to accommodate the thicker insulation. You can go beyond the insulation required by building code and save on cooling and heating costs in the long run. Other great materials are straw bales, ICF (Insulated Concrete Forms) and adobe.
Some new sustainable products are currently being developed and will be available soon. One company makes alternatives to concrete blocks from single-use plastic. It’s still in the testing stages but it’s a great way to reuse plastic waste.
Land and location considerations
Exterior walls and semi-underground berms take advantage of stable, cooling ground temperatures to insulate your home. The most efficient home is a cave, but it’s not a nice place to live! Caves contain incredible amounts of natural thermal mass and remain at a certain temperature, no matter what you do outside.
The goal is to create an “above ground cave” that looks somewhat natural.
I have built several semi-subterranean homes with some walls as high as 4 or 5 feet into the ground, taking advantage of thermal mass concepts. I have also built houses and insulated the soil from the outside, thus creating an above-ground cave. At least one elevation from the house, preferably on the side of the upper hill where the house is built into the hill, would be an ideal place for the berm. These houses are very temperature stable.
If you have any questions about sustainable building practices or sustainable living, please submit them to the Sustainable Ramona Facebook page and they will be answered in future articles.
Rob Lewallen is an architectural designer and general building contractor specializing in energy efficient design and construction since the mid-1970s. He is a member of the Ramona Design Review Board.