Know Your R-Value: How To Choose The Best Insulation For Your Home

R-value of insulation

Want to know more about the R-value of insulation? There are several types of insulation available so it’s vital to choose the best insulation material for your home, location and budget.

Here’s a rundown from Atticare, a leading insulation contractor serving the San Francisco Bay Area, Los Angeles and New Jersey.

How Are R-values Calculated?

The R-value of a material is a measure of how resistant it is to heat. You just divide the thickness of the material by its conductivity to get the R-value. And the higher the number, the better it will insulate.

We talk in terms of R-value for insulation per inch of thickness. So of course you’ll need multiple inches of insulation for it to be effective.

It’s not just home insulation that has an R-value. When considering the energy efficiency of a home we take into account the R-value of insulation as well as the R-value of drywall, concrete and other building materials.

What Is A Good R-Value?

The most appropriate R-value for your home all depends on where you live.

New Jersey

Toughing out the New Jersey winter? Then insulation material with a high R-value is a good investment.

New Jersey weather varies a great deal depending on whether you’re in the north or south of the state. So Atticare insulation contractors can advise you on the R-value of insulation precisely depending on your location. However as a general guide, the insulation should be between R-38 to R-60.

San Francisco Bay Area And Los Angeles

It’s not so cold in California so you’ll do well with around R-30 to R-60 for attics. Again, an Atticare insulation specialist will give you a more precise figure.

It’s worth considering a reasonably high R-value even in California because excellent insulation will help keep your home cool in the summer too.

What Insulation Has The Highest R-Value?

Not all types of insulation perform the same inch per inch, so here’s a ranking of insulation material. according to their R-value.

#1. Rigid Foam Insulation

Rigid foam is the clear winner if you’re looking for the highest R-value home insulation you can get. With an R-value of R-4 to R-6.5 per inch of thickness, it’s ideal for insulating exterior walls, including basement walls.

With such a high R-value, you don’t need such a thick layer to get a great insulating effect either.

Rigid foam insulation is a more expensive choice, but one a lot of people make because of the huge savings on energy bills that come with it.

#2. Foam-In-Place Insulation

You may have heard foam-in-place called spray insulation too. This type of insulation is very effective, even in freezing New Jersey winters. It comes in large cans, and we blow it into place. Once it’s in place it expands to fill every tiny space. This means that it seals all the tiny holes and cracks you never knew were there.

Foam-in-place insulation is made of polyurethane. It’s a flexible foam that you may have already encountered in bedding or carpet underlay.

This variety of insulation comes in two different types.

Closed Cell Foam

The densest option. In fact, closed cell foam insulation has an impressive R-value at about R-6.2 per inch of thickness.

Open Cell Foam

Open cell is less dense than its closed cell counterpart, at about R-3.7 per inch of thickness.

#3. Roll And Batt Insulation

Sometimes called blanket insulation, it’s usually made of fiberglass or rock wool. Roll and batt insulation is the most popular insulation across the United States because it’s cost-effective.

Traditional roll and batt insulation has between R-2.9 and R-3.8 per inch of thickness. However, these days there are high-performance rolls and batts too, which have R-values between R-3.7 and R-4.3 per inch of thickness.

What’s the difference between a roll and a batt? Batts are installed in pieces rather than being rolled out. It’s the same material though, and the R-value of insulation is the same.

#4. Loose Fill Insulation

This one is another one we blow in, so it fits into all the tiny spaces and insulates them.

Loose fill insulation can be made from fiberglass, rock wool, or cellulose. The R-value therefore depends on what it’s made from, ranging from R-2.2 to R-3.8 per inch of thickness.

First time home buyer? Read all you need to know about insulation here.

Which Type Of Insulation Is Most Effective?

Most Effective Insulators

As we saw above, rigid foam insulation and closed cell foam are the best performing types of insulation material you can get in terms of keeping your home the temperature you want it.

How Long Does Each Type Of Insulation Last?

Here’s the good news. As long as you choose a top insulation contractor like Atticare you may only have to insulate your attic once. Good quality insulation needs to be installed correctly, and then you’re on easy street.

#1. Rigid Foam Insulation And Loose Fill Insulation

As its name suggests, rigid foam insulation is good at keeping its shape over the years. Because pests can’t nest or gnaw into it, rigid foam insulation is kept dry and hygienic.

Loose fill insulation as shown above can also last 100 years. However, it does depend on what it’s made from. Cellulose is a good bet because it’s resistant to pests and moisture while being inexpensive and a good insulator, with around R-3.5 per inch.

Loose fill insulation isn’t as attractive to pests as traditional roll and batt insulation because it falls in on itself when they try to tunnel into it.

#2. Foam-In-Place Insulation

Foam-in-place insulation can last from  80 – 100 years. It doesn’t break down over time and won’t change form like fiberglass or cellulose.

#3. Roll And Batt Insulation

Cheap and easy to install, the downside is that roll and batt insulation has a comparatively short lifespan of 20-30 years. Of course it won’t last this long if you have dampness or mildew, or pests.

Learn more about choosing the right insulation for your home here.

What Can Damage The R-Value Of Insulation Material?

If your insulation has seen better days, the actual R-value will be much less than when it was installed. The following will cause the R-value of insulation to drop for all types of insulation.

Pest Infestations

Rodents, insects and birds can all wreak havoc with your R-value.

  1. Tearing up the insulation.
  2. Burrowing into your insulation.
  3. Soiling, which creates humidity and can lead to mold.


Moisture or mold inside or around the insulation means its R-value drops significantly.

This is because air is a better insulator than water. In fact, if insulation absorbs 20% moisture, its insulating properties can drop by over 50%.

Incorrect Fitting

It’s no good getting the best insulation with a high R-value if it’s not fitted precisely. You need a great insulation contractor like Atticare to make sure it’s fitted right.

This means no gaps or cracks where moisture or pests could enter, and insulation that’s laid smoothly over the whole space.

Get A Free Consultation On The Best R-Value Of Insulation For Your Home With Atticare

We live and breathe home insulation so we’ll be happy to go over your options plus which insulation material would be best for your home.

Call our knowledgeable team at (866) 692-5449 in New Jersey, the San Francisco Bay Area and Los Angeles or message us here.


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