Self-reliance and sustainability in the 21st century.
In Part II of this Series we are going to talk about more design features to be taken into consideration when you design your off grid home.
Windows: I could probably write a whole blog on windows alone but my main purpose in sharing our experiences in building a home for off grid living is to present a broad overview of many of the options we had to wade through and to give others who are following us a starting point to do their own research.
Windows are a critical factor in energy efficiency. Considerations range from the different types of windows to location in the house and the sizes chosen. Double or triple pane? Argon filled and type E? Wood, metal or vinyl?
Passive solar design is something I will cover in depth later on. Window sizes and location are a big factor in passive design. My research suggested that you use the following glass quantities based on square footage of your floor plan:
East side of the house 4%, west side 2%, north side 4%, and south side 7-12%. So if you had a floor plan of 1000 square feet, on the east side of the house you would allow for a total square footage of 1000 SF x 4% = 40 square feet of glass and so on. Always put the most glass on the south side of the house if you can.
Our house faces east by southeast which isn’t ideal. It had to face that way due to the hillside terrain we built on. So we couldn’t strictly adhere to the formula explained above but
The sun is one factor and cold is another. My wife Laurie made insulated curtains for all of our windows and they make a huge difference. Without them we would probably burn an extra 1-2 cords of wood per year.
In a perfect world your home will face south. I have a friend who was able to do just that. Even though they live in the cold country in northern Idaho, if it’s a sunny day, they are able to shut the wood stove down by noon because it gets too hot otherwise. They put most of their windows on the south side of the house and when the sun comes up it heats everything it touches. They have concrete floors and an indoor concrete planter that absorbs the sun most of the day. After the sun goes down, the concrete still continues to emit the heat that it soaked up earlier. Passive heat works and is something that should be considered in every home whether on or off grid.
Above or Underground: One of the best passive insulators is the earth. Anytime you can put part of your home underground you will be money ahead. Earth insulation will help you stay warm in the winter and cool in the summer. One whole side of our house is underground because we built into the hillside. It is a garage wall. With the earth on one side of the garage and our heated house on the other side, our garage never freezes and it has no heat! We get sub zero temperatures every winter. If I had my way, we would have built an underground house but the other half of this off grid partnership needs light and more light so we ended up with the one long wall. I’ll take any small victory I can get. As a bonus, our garage makes a perfect food storage area. It stays between 35 and 40 degrees from late fall to early spring, all with no heat.
Home size: In the case of energy efficiency size is an important factor. The smaller a home, the less energy it will use for both heating, cooling, and electricity. We chose to build a 1500 SF home mostly because the winters can get pretty long here and we thought it prudent to each have our own room to go to when we need to “get away”. I have a traditional man type room with all of my special man treasures and Laurie has a crafts room with a lot of windows and a loom.
Before we bought this property we had a nice cabin not too far from here. It was 800 SF with a 400 SF loft. It was quite comfortable for two people. 1500 SF is nice but the 800 SF footprint would have been better in terms of energy consumption. Many of you will think we built too large and others will wonder how we get along with only 1500 SF. There is a current trend in some circles for really small homes measuring as little as several hundred square feet. Build the home you need but the smaller the better. Note: Due to the 12” wall thickness our floor area is actually 1400 SF.
Eave Length: Another feature of passive design is your roof eave overhang. Design your eaves to extend out far enough in the summer to shield the sun from your windows and in the winter to let the sun into your windows. It’s going to depend on where you are located. Eave length will be different in the southern part of the U.S than the northern. Shielding the sun in the summer months helps to cool your home. Conversely you want to allow the sun to heat your home in the winter. Passive heating and cooling are factors in sizing your off grid system. The less need you have, the smaller your energy system will need to be.
Ceiling heights: The same applies to ceiling heights. Higher ceilings equal heat loss. Many people love the look and feel of spacious high ceilings. That’s nice but you know where the heat goes. It goes up and the higher the ceiling the more heat is required to keep you warm, down where you live. Keeping your ceilings low is an easy way to keep your energy needs lower.
Passive design is a wonderful thing to incorporate in any home being built. Anything you can do to utilize the natural things that are available to us should be taken advantage of. Why pay for heat and light when you don’t have to? We have six solar tubes in our home that allow us to see with natural light all day long. Without them we would have to turn on the lights, even in the daytime, because we don’t have windows in every room. There are many ways to use what’s natural and free to heat, cool, and provide lighting in your home.
Coming up next: Appliances, heating, and electrical fixtures.