Friday, November 09, 2007
Insulation will lower heating bills
By Ann Robinson and Annie Vernon
The weather is getting colder, but saving on the heating bill this winter shouldn't mean you have to cuddle under four blankets to stay warm.
If your heating bill is through the roof, then that may be exactly where your heat is escaping — through your roof and walls.
Although insulation is probably not the first thing you think of when planning a remodeling project, it may be just the thing to achieve a warm, comfortable atmosphere in your new rooms.
The right insulation — material added between wall studs or roof rafters to prevent outside air moving inside or vice versa — keeps your home warm in the winter and cool in the summer. The better the insulation, the more energy efficient your home will be, meaning lower energy bills and a more comfortable living space.
When you think of insulation, you probably think of the most common type — that itchy, pink or yellow fiberglass batting. It comes it a variety of thicknesses. The thicker the material, the better the insulating properties. Insulation effectiveness is noted by an "R" factor with high numbers being the best. So, fiberglass that fits into a 4-inch stud cavity has an R factor of 13; a 6-inch batt is R-19; and a 12-inch batt (for roof rafters) is an R-38.
You can get even higher R-values with another insulation option. You can insulate almost every crevice in a wall with spray polyurethane foam. This is fun stuff to watch being applied!
First, the installer dons a NASA-like suit, and, using a gun, he sprays a thin foam mist that sticks to everything it touches. Within seconds, it expands from 20 to 120 times its original thickness, filling the space where it was sprayed.
You might be wondering why the space suit? This protects the applicator from breathing in any foreign substance. Once the foam cures and hardens (which takes minutes at best and a few hours at worst, depending on how well-ventilated the area is), the insulation is relatively inert and does not emit odors or allergens.
SPF systems come in two varieties — high density and low density. High-density SPF is used when you want high-moisture resistance and insulating values. The R values for this type of foam range from 5 to 7 per inch of foam. It typically expands to 26 times its original volume. Low-density SPF systems are suitable when insulation, an air-barrier and some sound insulation are needed. The R value for this type is about 3.5 per inch. This type of foam expands approximately 120 times its original volume.
The low-density foam is an air barrier, not a moisture barrier. It is an open-cell structure that does not wick water but will allow it to enter under pressure. The water then passes through the foam and drains by gravity. It won't trap moisture like other materials, such as wet fiberglass insulation, which is a breeding ground for mold and food for rodents and insects.
When the low-density foam dries out, its thermal performance is fully restored. The higher-density foam has a closed-cell structure that resists water absorption. Thus, it offers a superior barrier against rain or weather.
There are some environmental issues when it comes to using the SPF systems and its blowing agents. Most of the low-density systems use water as the blowing agent, but high-density foam requires a different agent. The insulation industry has made progress, replacing less environmentally desirable agents with a new medium that does not contain chlorine and which has no ozone-depletion potential. Though it may take years for this agent to leave the atmosphere, many feel that this is more desirable than the amount of energy used in producing blown fiberglass insulation, which consumes large amounts of oil and natural gas in its manufacturing process.
We can safely say that whatever type of insulation you choose, it will help lower your heating and cooling bills and will aid the environment by increasing the energy efficiency of your home. So, don't forget to add insulation to your list of decisions you will have to make when you remodel your home. It could save you a bundle on future heating bills. As always, we welcome your home architect design questions at firstname.lastname@example.org.