The Value of Insulating Your Home

Your household temperature should not be easily affected by the temperature outdoors. You can insulate better to prevent outdoor temperatures from easily penetrating through your walls, ceilings and floors.

Although most of us have a general idea of the value of having a well insulated home, it may not be as obvious as to how much a little insulation can help, especially if your walls and ceilings are not insulated at all.

OLDER WOOD FRAMED HOMES

Most homes built within the past forty to fifty years are nearly guaranteed to have some insulation in the walls and ceilings, but when you start getting into homes built prior to the 1950’s, things can change radically.

A good example is with ‘company homes’ that were thrown up quickly to offset a housing need brought on by area industry. These homes often lacked insulation of any kind and were inherently drafty since there was no true seal between the indoors and outdoors other than a layering of boards that served as its siding.

When looking at these older homes, the outside wall construction would generally consist of a layer of plaster and lath boards, a four inch empty space, wooden shingles, tar or asbestos shingles and perhaps an overall layer of aluminum or vinyl siding. Even if you round the values up, the wall R-Value might be as low as an R-2.

What is an ‘R-Value’? R values are values assigned to materials with respect to how easily heat can pass though them. The easier it is for heat to pass through, the lower the ‘R’ or ‘Resistance’ to heat value. Likewise, the harder it is for heat to pass through, the higher the ‘R’ or ‘Resistance’ to heat value.

In newly constructed homes, the typical wall R-Value is on the order of R-20 to R-30, which is at least ten times higher than many older homes. Based upon this alone, you could see how the walls of an older home could allow up to ten times the amount of heat to escape, as compared to a newer home. This is why the simple act of insulating an older home can create such a major impact on heating and cooling costs. Whether you do it yourself or hire a professional, your savings could be substantial.

Insulating the walls and attics/ceilings in older homes can be performed in a few ways:

Blown In Insulation - This involves drilling two inch holes into each bay within each wall and using an insulation blowing machine to force pulverized insulation into the wall cavity. This can be highly effective, but it's impossible to guarantee that the full wall cavity gets protected since any obstruction within the wall, such as piping, wiring, plaster and fire stops, will prevent filling the cavity as completely and as tightly as possible. Even with its drawbacks, for a three inch to four inch deep outside wall, this could increase your R-Value from R-2.0 to R-13 and save up to six times the amount of heat that had easily escaped before.

Mild Renovation - This involves adding a one inch sheet of foam board (R-5) to your existing inside walls and then covering them with new drywall. It's not as effective as filling the wall cavity and requires that electrical devices, window frames, door frames and moldings get adjusted to work with the new wall depth, but it can be done at any time of the year by anyone with some handyman skills. Adding one inch foam board and half inch drywall to a three inch to four inch deep outside wall would increase your R-Value from R-2.0 to R-7.5 and save almost four times the amount of heat that had easily escaped before.

True Renovation - This involves totally ripping down any old plaster wall sheathing and then properly sealing and insulating the wall space with insulation bats or foam insulation. Overall, this is the best option since this would allow you to fill the entire wall cavity and also seal any cracks, thereby reducing outdoor cold air infiltration as well. If combined with also replacing the siding, you could increase your R-Value from R-2.0 to R-20 and save up to ten times the amount of heat that had easily escaped before.

OLDER BRICK CONSTRUCTED HOMES

Another experience I have had with older homes is with brick home construction. Four inch bricks have an R-value of .8, so even when they are doubled, your R-Value is only 1.6, plus brick allows heat or cold to travel through it at a much greater rate than wood.

Not only do these older brick homes have no insulation, there isn’t even any space provided to add insulation or blow it in. The inside walls may look like the same plaster walls on wood framed homes, but they are just an eighth of an inch away from the brick itself.

When faced with insulating the outside walls of an old brick home, your only recourse is to rip off the old plaster and either build a entire two by four wall in front of the brick so that you can install R-13 insulation and add wiring, or, if you are very limited on space, you can frame the wall with two by twos and fill the voids with 1 ½ inch foam board (R-7.5).

ATTIC SPACES

In addition to insulating your walls, the attic space needs to be thoroughly insulated and sealed. For colder climates, you want to stop your heat from rising out through the attic space, and in warmer climates, you want to stop the baking heat of the sun from transferring down into your home from the attic space.

In Older Homes - Attic spaces vary greatly in old homes whether they are single, double or row-homes, but the same principles as described for wall insulating could be applied. Many attic roofs on older homes, follow the roof line and could simply be treated the same as a wall space where the only deviation is where there may be small crawl spaces around the borders of the roof where it meets the floor. These spaces could easily be insulated using either insulation bats or blown in insulation. Since heat rises up, it is very important to not neglect adding insulation to the attics of older homes.

In All Homes - The one primary issue with insulating attic spaces is with ensuring you maintain some level of outside air circulation so that condensation build up does not occur. At no time should the insulation block airways from the eaves or be in direct contact with the inside of the roof layer.

A common problem in many attics, especially in modern homes, is that we have chosen to use them for storage. We keep our Christmas decorations up there, old toys, baby furniture, etc., and that’s all fine, except, these items generally get stored on top of plywood sheathing that was laid down on top of the ceiling joists.

The very moment anything is laid down onto the joists in the attic, any blown in insulation was crushed and its r-value value was diminished, plus, moisture can often get trapped under the plywood sheathing, regardless of insulation type, and result in mold growing on the drywall ceiling below.

Alternatively, you can have a contractor build elevated storage spaces in the attic that do not crush the insulation nor trap condensation. This process generally results in less storage space, but it will result in your attic insulation doing the job it was designed to do.