About House Insulation

With rising energy costs, house insulation is becoming a very popular subject. It's much easier to make sure it's done right when building a new home, than when you're trying to upgrade an older one.

In either case, if your house insulation is not fully encasing your home, a sizable portion of your heating and cooling costs are going directly to the great outdoors. So "encase your living space."

How well your insulation will keep the cool air away from the warm air is measured by something called an "R rating." Different insulating materials have different R ratings. There are recommended minimum R ratings for various locations depending on climate.

If you live in a warm climate, you could get by with an R-11 rating in walls and R-19 for attic insulation. Colder climates could be as high as R-38 in the walls, and attic insulation could be as high as R-49.

House insulation should be put into any cavity located between heated and unheated spaces, in essence, creating an envelope. Attic insulation is the most important.

It has been calculated that fuel bills can be cut by as much as 30% by properly insulating an attic. Remember that a well insulated attic MUST be properly ventilated as well.

Types Of House Insulation

The list below lists the various types of insulation and the R ratings for a typical attic floor with 10" high joists, and a typical wall with 4" wide studs. The only item on the list which you could think about doing yourself is the fiberglass batt & blanket. Other than that, leave it for the pros.

Any material that is blown or poured should not be used in walls, since it will settle over time, leaving a gap at the top of the wall. Sheathing is the 3/4" boards used as the faces of the walls where there is no sheetrock (beneath the siding).

You should therefore add the rating of the sheathing to the rating of the adjacent material. Here's the list.

Fiberglass batt & blanket: 1" = 3.27; 10" floor = 32.7; 4" wall = 13.08

Rock wool batt & blanket : 1" = 3.2-3.7; 10" floor = 32-37; 4" wall = 12.8-14.8

Fiberboard sheathing: 1 sheet = 1.32; at wall = 2.64 (2 sheets)

Blown in fiberglass: 1" = 2.2-4.0; 10" floor = 22-40; 4" wall = 8.8-16

Blown in rock wool: 1" = 2.9-3.6; 10" floor = 29-36; 4" wall = 11.6-14.4

Blown in cellulose: 1" = 3.2-3.8; 10" floor = 32-38; 4" wall = 12.8-15.2

Poured vermiculite: 1" = 2.27; 10" floor = 22.7; 4" wall = 9.08

Poured perlite: 1" = 2.7; 10" floor = 27; 4" wall = 10.8

Sprayed polyurethane foam: 1" = 6-7.3; 10" floor = 60-73; 4" wall = 24-29.2

This type of house insulation has to be installed by a professional with special mixing equipment. This material doesn't shrink or settle.

It blocks any air infiltration because it conforms to the shape of the walls, and it acts as a moisture barrier. This is relatively expensive, but compared to what they will save in the future, they are your best bargain.

NOTE: You probably don't have this option because it's no longer legal, but you might see urea-formaldehyde foam insulation, which has a very high R rating. This should not be used because it gives off toxic fumes when burned. So if your house burns, you neighbors die from the toxic fumes.

There are other insulating materials which I have not included here because they are not typically used in homes. There are reasons for these things. Although, if you live in the desert, you might consider wrapping your house with aluminum foil.

When speaking to your architect, make sure he/she specifies the material you want (and the R rating) for house insulation - in particular, for attic insulation.

Once the builder sees it on the construction documents, he will act accordingly. Also discuss the proper ventilation. It all works together to provide proper air quality and energy conservation.

And, of course, if you have any specific questions about house insulation, or attic insulation, contact me here.

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