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What is the purpose of insulation?
Insulation works to keep your home cool in the warm months of the year and warm during the cold months of the year. It prevents your “conditioned” air, either warm or cold, from leaving your home. Essentially, insulation resists the flow of heat. The laws of thermodynamics dictate that heat will always flow from where it is warmer to where it is cooler. This means that without insulation, all the heat in your house would migrate outside where it is cold. Conversely, all the cool air you have just created for your comfort would then attract the heat from outside where it is hot.

By managing the flow of heat, and preventing it from moving where it shouldn’t, you’ll save a great deal on your energy bills.

Sound control is one more reason for using insulation. One of the biggest reasons for adding extra insulation is to keep bathroom sounds from migrating throughout the house, and home theaters or “teen rooms” are other popular rooms to add an extra sound barrier of insulation.

When do you know if you have a problem with your insulation?
It is good to look for insulating problems by evaluating whether you have insulation that meets the minimum standards for each area of your home. Always make sure you have plenty of insulation up in the attic area. This is an area where you have plenty of room for extra insulation and it will pay off in a big way by preventing heat from transferring in the wrong direction.

Other areas to check in addition to your attic are basement walls, areas above crawl spaces, cathedral ceilings, the short walls in a finished attic (called kneewalls), between interior walls to muffle bathroom sounds, floors over unheated porches or garages, and any place you may wish to have additional sound control.

How much insulation is needed in each area of your home?
The U.S. Department of Energy (DOE) and the IECC (international Energy Conservation Code) have established insulation levels for each climate zone. Check the climate zone where you live to evaluate whether or not you have the necessary minimum required levels.
What does R-value mean?
R-Value stands for “resistance to heat flow”. The higher an insulation’s R-value, the greater its insulating capability will be.
What are my choices in terms of insulation?
There are several different types of insulation that is used for home insulating purposes. Most everyone is familiar with the paper backed fiberglass insulation. In addition to that there is cellulose, cotton, foam, and mineral wool.

When making the choice of which insulation to use for your home you need to make sure that you not only meet the minimum necessary requirements, you also want to choose the best insulation for the project. Given the difficulty of reaching certain areas of your home, you are not likely to want to go in and replace insulation in these hard to reach places every year or so. It is best to insulate them properly from the beginning.

Fiberglass does not settle much over time, nor does rock and slag-wool insulation. Cellulose, on the other hand, will settle by as much as 20% and sometimes as much as 50% if it were to ever get wet. When using cellulose insulation, the Insulation Contractors Association of America recommends using 25% MORE insulation in order to avoid losses in your R-value over time.

Which choice is the safest?
Safety in insulation is usually evaluating how combustible it is. Cellulose, made from wood fiber and shredded newspaper is very combustible. Even though they are treated with fire retardant chemicals, it is not fireproof, and its fire retardant capabilities diminish over time. Cellulose has even been shown to fail the standard test only six months after installation.

For this reason, most people tend to choose fiberglass both for its noncombustible nature and the fact it is made of sand and recycled glass, both of which are considered to be renewable sources.

Which choice is the most energy efficient?
Neither choice is either more or less energy efficient than the other. What you’re looking for is R-factor, which can be combined with various levels of insulation to get the required number you desire.
Which choice is not affected by water?
Cellulose will compact and lose a great percentage of its R-factor when it gets wet. Even when it dries, it will never return to its original R-factor. If cellulose is used to insulate an area that stays moist, you could develop a very real mold problem. Fiberglass does not compact or lose its R-factor rating when it gets wet.
What is the environmental impact of using insulation?
Because more people are asking for environmentally friendly building techniques and materials, builders are becoming more conscious of their choice in building materials. Insulation is one of those materials. Fiberglass is made up of recycled products, and the fiberglass industry recycles more material by weight than any other type of insulation used. Cellulose insulation seems like a good recycling choice, but it uses recycled newspaper and cardboard that could instead by recycled to be reused as paper goods rather than felling more trees. Because it takes three times as much cellulose material to produce the same R-factor of insulation, it is not considered to be the wisest choice. Fiberglass is made from sand, which is considered to be a rapidly renewable resource.
What is air infiltration?
Air infiltration represents loss of heated or cooled air due to leaks you may have in your home. Up to 40% of your energy can be lost due to air infiltration. Sealing electrical outlets with gaskets will help. Identifying areas around windows, doors, fireplaces, ductwork, and perimeter joints will help too. Seal these leaks before you put any insulation in place. If you just rely on insulation, you will suffer severe increased energy costs.
Do you have to remove insulation to put new insulation in its place?
No, you do not. The R-factor of insulation is additive. This means that if you have a layer of insulation in your attic, but you want to add more, placing an additional layer of insulation will add to the existing R-factor already in place. To get the best result, place the rolls of insulation at right angles to the existing rolls. This way you can tighten up on any potential air gaps.
Are there any rebates for insulating your home?
Check your local area to see what rebates or tax breaks you might qualify for. Many states offer financial incentives to increase the insulation in your home.