To answer the question of what insulation is best for your home, we must first determine your goals. Whenever we look at improving insulation, we will ask you some questions about your goals, home comfort issues, and energy costs. Each of these factors and many more will help determine which insulation is the best fit. When we inspect the attic, we also look at the existing types of insulation that are in the home and the construction features that may impact what kind of insulation would work best.
There are three main forms of insulation; blown, batt, and spray foam insulation. Each of these forms come in a few main types of product. Let’s look at each of these and in what applications the perform the best.
This is a type of insulation that comes in a bag and requires an insulation blowing machine to fluff it and blow it through a hose into the house.
Blown insulation is mainly used in flat attic areas but can also be installed in walls and floor systems. There are two main materials that blown insulation is made from.
Blown Fiberglass - This insulation is an excellent choice for a new or existing home to bring the insulation levels up to the ideal level for peak performance. Fiberglass insulation is a very clean product and has come a long way from the old, itchy insulation that the name may bring to mind. The insulation we install feels almost like cotton. The two biggest benefits of fiberglass insulation are that it is very low in dust and it doesn’t settle, hardly at all, over time.
Blown Cellulose – Cellulose insulation is a great product because it is made from mostly recycled materials. It has been treated to be fire resistant and can also help deter bugs. If there is already cellulose insulation in the attic, this is a great product to use to upgrade the insulation levels.
By far, the most common form of insulation for walls, crawlspace, and many attics is batt insulation. It is usually made from fiberglass and is formed into pieces that fit between the spacings of wall studs or the floor and ceiling joists. Batt insulation is a great product because it can be easily cut to size and comes in a consistent thickness giving an even insulation layer.
When batt insulation is installed in walls, that face the attic (also called knee walls), it performs best when covered with an air barrier. The insulation factor (or R-value), that is given to a batt of insulation doesn’t consider air moving through the insulation. Since fiberglass batt insulation is porous, it only performs at it’s peak when accompanied by an air barrier on all 6 sides. This is why it is so important to seal any penetrations from wiring and plumbing and install an air barrier over the back of the insulation if it is facing the attic.
Spray Foam Insulation:
The unique feature of spray foam insulation is that it both insulates and stops air flow. This means that it can achieve the best energy performance in a home because it stops air from escaping and significantly slows heat transfer. It is sprayed onto the walls, attic or floor and immediately expands when it contacts the building surface. To achieve the right thickness a few applications of the foam may need to be applied. Since this product rapidly expands it will often extend out further than the wall framing. When this happens, a tool will be used to shave it even with the wood framing so that the drywall can be installed over it.
Spray foam is a great product for installing in attic when the floor of the attic is mainly decked. It is typically installed on the roof deck and insulates the entire attic area making the space much more comfortable for storage as well as greatly reducing the heating and cooling cost for the home.
No matter what insulation product you use, the most important thing is how it is installed. Any of these types of insulation can be almost useless if they are improperly installed. To get the best efficiency and performance from your home, your insulation should be an even coverage, without gaps, and installed in the right location. And remember, the best insulation is the product that fits your home and your goals the best.