Q–We would like to put a sun room on our house so we can grow plants all year. A sun room should keep our house warm in winter and looking good all year. What do you think?
A–The decision to build a sun room depends on where you live.
If you live in the South, you may end up with a lot more heat in the house than you want or need. Sun rooms work great in the North, where there is a fair amount of wintertime heating, and the heat gain from the glass room keeps the house more comfortable.
Sun rooms or greenhouses are typically built in the south wall of the home. Incoming heat is stored in a thermal wall and thick floor. Tanks of water also can be used for heat storage. At night, when the temperature in the room drops, the stored heat is released by the thermal mass.
Note that in the summer, you can use the sun space to help with cooling by allowing heat to escape through its vents, and the storage wall absorbs heat before it can get into the home. If your climate means that your home uses a lot of air conditioning even in the winter months, though, you may have an overheating problem.
If you want the sun room for heat, then growing plants is going to cut down on that benefit. Depending on the type of plants you grow, evaporation from the leaves can cut the heat from the sun space by as much as 50 percent. If you live in a dry part of the country, the plants can provide the benefit of acting as natural humidifiers and adding to your home’s comfort.
Think about why you want a sun room. If you live in a cool climate and want to take advantage of winter heating benefits and grow some plants, then it can be a super idea. If your climate is hot and you try to keep heat out of the house even in the winter months, then you need to consider the consequences before building the room.
Q–We’ll need a new roof soon, and I would like to get the kind of roof that will keep my house most comfortable. What do you recommend?
A–The best recommendation I can make is to begin with aesthetics. What type of roof will look best on your home? I’m convinced that energy efficiency will never become popular if people have to use products and building styles that they don’t like or want for their homes. Once you’ve decided on the type of roof that will look best, then you have some flexibility in the specifics.
Here’s what I mean. Researchers have found that both the color and the type of roof material affect energy consumption and the comfort level in the home. They measure the performance of roofs by looking at the solar absorptances of the materials–the extent to which the surfaces will convert solar radiation into heat. A solar absorptance rating of 1 means the surface will convert all the solar radiation into heat; a surface rated at zero will convert none of it.
