If you're building a new house, insulation is one of the most important steps to creating a comfortable and affordable home environment. It definitely will pay to better insulate as it is being built than to retrofit later. Don't cut costs on insulation. To save money on the installation, insulating is a simple process that for the most part can be done by the homeowner. If you already have a new home that is built, you can't do much to change the basic wall insulation without it costing a lot of money, but you can better insulate parts of your home yourself.
Insulate your walls. You can use traditional thick and fluffy fiberglass insulation, or you can use the new foam-type insulation that comes in thin, efficient batts. However you do it depends on your preference, your environment and the space you have.
Insulation is measured in R-values, and there are charts to show how much R-level insulation you need to maximize your insulation efficiency, depending on the environment you live in. If you live in the north you could need R-19 in your walls, but if you live in the southern United States you could need only R-13. (See Resources.)
You can also use loose, blow-in insulation, but that is a bit more complicated and requires the rental of blower equipment. You can get the fiberglass insulation with or without a paper backing that acts as a vapor barrier, but you will need to install some kind of vapor barrier. Insulating your home needs to happen before the drywall goes up and while the studs are exposed. If you need to fit higher R-value insulation in your walls, 2-by-4 wall studs won't hold more than R-13 fiberglass batts, and you will either have to use the new foam style of insulation or use 2-by-6 studs for your walls. You may also need 2-by-6 walls if you use blow-in insulation. If you're not sure of the difference between 2-by-4s and 2-by-6s, the first is actually 1 1/2 inches by 3 1/2 inches, and the latter is 1 1/2 inches by 5 1/2 inches. You can use a standard tape measure to check. Fit the insulation in between the wall studs, and cover with a plastic vapor barrier. Staple the plastic or paper barrier in place.
Seal your windows and doors. Use the same type of insulation to fill in areas around your windows and doors. If there is an area that is too small to put in insulation, you can use cans of spray-foam insulation, but you must be careful because the foam usually expands a lot. Be very conservative and find foam that doesn't expand much. This foam cannot be used in some areas, such as around heaters, because it is extremely flammable when applied. Use weatherstripping around doors to help make your openings airtight when they are closed. Though it is commonly used for doors, you can also apply weatherstripping around windows to close any leaks.
Consider the rest of your house. Insulating crawl spaces is controversial because just as many experts say that it should be ventilated as those that say it should be sealed. Depending on whom you talk to, insulating there has some prerequisites and may cause a problem with radon gas. Is it is also debatable if insulating a crawl space does much to better insulate your living area. Research before deciding.
Insulating attics is becoming more popular, and some say it can save you 35 percent on your energy bill. Insulating your attic usually requires much higher R-value insulation such as R-39, because there will be no drywall or anything else covering the insulation. Use the same techniques to insulate your attic as your walls except that if you have an opening in your attic, such as with a vent cap, and you want to keep air flowing to the opening, you will have to use some plastic batts underneath the insulation to keep the airway channel opened. The air flow is important to help keep snow from melting on the hot parts of your roof and then cooling and forming ice dams on the cooler part of your roof. This can cause leaks and destroy your shingles and your roof.