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Insulation 101

February 25, 2013

Insulation – How it Works

To understand how insulation works, we must first understand how heat works.

Heat is constantly trying to move to cooler areas. Think of the rooms in your house: if your upstairs bedroom is a warm 90 degrees but the attic space above that bedroom is a cool 34 degrees, heat will make its way through the ceiling to fill that cool space and make it warmer. This is all due to the second law of thermodynamics. Simply put, higher-energy molecules (warm air) like to spread out to places with lower-energy molecules (cold air).

As a result, your upstairs bedroom loses heat and cools down. Since your heating unit will continue pushing hot air into your upstairs bedroom, you’re letting money float right out into the cold night air. This process is called conduction, and it’s totally unstoppable—unless your home is insulated property.

Insulation fits into the voids of your walls, floors, attic, crawlspace and basement to prevent the unwanted flow of heat—regardless of the season. (This can happen in summer, too; the outside heat is constantly trying to enter your home, so your AC unit works to remove that heat.)

Understanding R-Values

The ability of a certain type of insulation to resist the conductive flow of heat is defined objectively as its “R-value.” This number depends on the insulation’s thickness, density, and the specific components that comprise it. The higher the number, the more effective the insulation is.

And since insulation can be layered, all you need to do to find the R-value of a multi-layered section of insulation is to add them all up. These numbers are important to know so you can follow the federally recommended amounts of insulation for your specific climate and type of home.

How Climate Affects Insulation

Homes in Fargo simply need more insulation than homes in Southern California. Fargo experiences more extreme lows than SoCal, and for that reason heavy-duty insulation is needed to halt the dramatic flow of heat through floors, ceilings, and walls.

However, areas like San Diego do experience unique weather that requires insulation of a certain kind. It is recommended that San Diego homes use R30 to R60 insulation in an un-insulated attic, and R25 to R38 if three to four inches of insulation are already present. In the floor, R19 to R25 is recommended. Moreover, siding plays a part in how much insulation you need: siding protects against convective heat loss (i.e., wind). When you replace siding in San Diego, it’s recommended that you blow insulation into the wall cavity, install R5 wall sheathing beneath the new siding, and put it all back together again.

Here’s the tricky part: knowing what type of insulation fits your home best. And that’s where Bob Jenson’s experts come in.

Types of Insulation

There are several types of blown insulation from which homes in San Diego can benefit. We hope this helps you decide which type is best for you, be it loose-fill insulation or foam-in-place insulation.

  • Loose-fill insulation: It takes special pneumatic equipment to blow this type of insulation into cavities in the floors, walls or ceilings of your home. Loose-fill is made of rock wool, fiberglass, cellulous, or another advanced composite that easily conforms to abnormally shaped spaces like attics.
  • Foam-in-place insulation: This is another type of blown-in insulation that is best handled by experienced professionals. There are two types available for residential use and both use polyurethane as a base ingredient: open-cell foam, which expands for great coverage using air pockets; and closed-cell, which is filled with a specific gas to more effectively help the insulation expand to fill gaps.

Closed-cell foam is twice as effective as open-cell foam, though it also comes with a slightly higher price tag. However, its effectiveness is so great that over the longevity of the insulation, you will have saved that much more money due to decreased heat loss out from and into your home.

The Professional Touch

Since installing insulation deals with chemicals and irritants, it is dangerous to install it yourself, unless you’re a professional. Plus, blowing insulation around light fixtures and other electrical components is difficult, and if done incorrectly, could cause damage to areas of your home that could be costly to fix.

If you’re not sure what shape your insulation is in, or if you notice inefficiencies in your home’s heating and AC, have us check it out. We offer free insulation estimates for any type of home. And when your home is properly insulated, you’ll enjoy both a comfortable environment and a smaller energy bill—all year long.

About The Author

Bob Jenson

For over 45 years, Bob Jenson has been providing quality heating and air services to the San Diego community.

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