How To Insulate Your Home

by heather

I know I’ve already written about how to lower your heating bill for the winter, but I left out insulation because it truly deserves its own article.

Everyone always talks about how much money you can save on energy costs by adding insulation to your home. And there’s no doubt that all the buzz is well deserved. But, how much insulation should you add? Where should it go? Does insulation really save energy? Can it really cut your heating costs and save money?

Those are the questions I’m tackling in this post.

Insulation: What Is It?

Think of the last time you went camping on a really cold night (if you’re not a camper, then use your imagination here). Chances are you had a down or synthetic sleeping bag that was really fluffy once you took it out of your pack and aired it out. Remember how nice it was to snuggle down into that sleeping bag? You probably slept really toasty all night long, even if it was 10 degrees outside.

Well, your home’s insulation works very much like the sleeping bag; it creates a buffer between you and the cold because it’s made of particles that slow the transfer of air.

Heat is always looking for a way out, but when it hits the insulation it gets trapped in the fluffy particles, which means that expensive warm air is still kept inside, keeping your house warm.

Types of Home Insulation

1. Fiberglass Batts

The most common type of home insulation is fiberglass batts. These are the big, fluffy rolls you’ve seen at Home Depot or Lowes, and will usually have a big Pink Panther on the logo.

The neat thing about fiberglass is that it’s actually made of molten glass, which is then spun into those delicate, soft fibers.

Fiberglass batts are made to go in between studs, and underneath ceiling joists and under floors.

Now, it’s important to realize that fiberglass insulation works just like a down sleeping bag; if you crunch it up and cram it into small spaces, it’s not going to keep you as warm. The more open and fluffier it is, the more air it’s going to be able to trap (and the more energy efficient your home will be).

And I’m sure you don’t have to be told, but if you install this, be aware that it’s very itchy. Wear goggles, a mask, long pants, and long sleeves. When you’re done, make sure you take a shower.

2. Loose Fill Insulation

Loose fill is is made up of fiberglass, mineral wool, and cellulose (cut up paper bits). It’s blown in by a professional, usually into preexisting walls. But, it can also be blown into attics as well.

The upside of loose fill is that it’s not very expensive.

The downside? It’s very messy and dusty.

3. Spray Foam Insulation

Spray foam insulation is made of polyurethane foam, and it works by expanding as soon as it hits the surface of whatever it’s sprayed on.

The advantage to spray foam insulation is that it can get right into the tiny cracks and openings that regular fiberglass insulation misses. It makes your home incredibly tight and energy efficient. It also gives you a higher R-Value per square inch (we’ll be going into R-Value in a minute).

The bad news is that it can be expensive. It must be installed by a professional, and costs are around 3 times higher than regular fiberglass. But, most experts say that spray foam insulation will save you 30% on your heating bills, paying for itself in about five years.

4. Cellulose Insulation

Cellulose insulation is made from recycled newsprint that is treated with flame-retardant chemicals. It’s an appealing choice because it’s environmentally-friendly, and also gives a fairly high R-Value per inch.

So, those are the most common types of home insulation. Now, let’s look at R-Value.


R-Value is what measures the insulation’s resistance to heat flow. The higher the R-Value, the more resistant is is (which is a good thing).

R-Value is measured using the insulation’s thickness, material used, and density. And different parts of your home needs different R-Values.

For instance, the attic is the #1 place where heat is lost. So, experts recommend having an R-Value of at least 38-42 for this space. Side walls should have an R-Value of 11-18.

Your specific R-Value requirements depend on two main factors: where you live, and how old your house is.

To determine your specific R-Value requirements, you can check out this nifty calculator the Department of Energy put out.

If you’d like to see recommendations for your specific part of the country, you can check out this great map put out by Energy Star.

Now, measuring the R-Value of your home’s existing insulation can be a bit tricky.

First, measure the depth of your current insulation with a ruler. Then, follow these guidelines:

If you have loose fibers (like blown insulation):

  • Pink or Yellow in color- depth x 2.5
  • Dense Gray or Off-White in color- depth x 2.8
  • Small gray flat pieces or fibers- depth x 3.7

If you have fiberglass batts:

  • Yellow, pink, or white in color- depth x 3.2
So, for instance, if your attic’s blown insulation is 15 inches deep, take 15 inches multiplied by 2.5, which will give you an R-Value of 37.5.

This information comes courtesy of the U.S. Department of Energy.

Where To Add Insulation

1. Attic

If you want to get the biggest bang for your buck, you’ll maximize your home’s energy efficiency by adding insulation in the attic first. This is also the easiest place to start, which is nice if you’re doing this project yourself.

If you’d like more information on the specific steps for adding attic insulation, then don’t miss this informative article put out by the U.S. Department of Energy.

2. Garage

Most people don’t think about their garage when they’re considering energy efficient upgrades, but if it’s not insulated your garage can really add to your heating costs. If you have a small room or apartment space above your garage, then insulation is even more important.

3. Crawlspaces

If you have floors that go over an unheated basement or crawlspace, then you definitely need to add insulation under these areas to ensure that the cold air is not seeping into your living areas. This is only going to cause your furnace to work harder (which, of course, costs you more money).

4. Ductwork

Think about this for a moment: if you have ductwork that goes through your unheated attic or basement, then the air that’s going through those thin metal pipes is going to lose its heat fairly quickly, which means your furnace has to work that much harder to get your home to its preset temperature. The U.S. Department of Energy estimates that the average home loses 10%-30% of energy this way.

This is why insulating your ductwork is so vital. If you’d like to learn exactly how to begin insulating your ductwork, you can check out this great article from the, you guessed it,the U.S. Department of Energy.

5. Exterior Walls

Insulating your home’s exterior walls is tough, especially if you live in an older home that might not have any insulation at all. Usually, you have to use blown insulation, which has to be done by a professional.

Adding insulation to your home doesn’t have to be an expensive job. Start where it counts: in the attic. And then keep going as your budget allows. With all the experts claiming that proper insulation can cut your bills anywhere in the range of 10%- 50%, it’s definitely worth the investment.

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{ 1 comment }

Craig October 10, 2008 at 12:51 pm

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Would you mind replying to me via email and I can share more details for your readers….thought this would be a great fit for your blog.


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