Open and closed cell foam are two types of insulation that provide excellent energy efficiency. But which one is best for your project? We’re about to look at open vs. closed cell foam along with their strengths and weaknesses. By the end of this page, you’ll have a much better idea of which product is best for your project.

What is the difference between open cell and closed cell foam insulation?

Open and closed cell insulation are high-quality insulations that have excellent longevity. They are both liquids that, once sprayed on a structure, rapidly expand into a foam. However, the bubbles, aka cells, that make up the foam have different characteristics.

  • Open cell foam has cells that are intentionally left open. It results in a soft, flexible foam that is easy to work with.
  • Closed cell foam has bubbles that are closed over. This type of insulation doesn’t allow any moisture or air inside; it is dense and rigid.

Which has the best R-value?

R-value is a measure of an insulation’s thermal efficiency. It varies depending on the type of insulation and also by brand.

Closed cell foam has a much higher R-value than open cell foam thanks to its density. It usually ranges from R-6 to R-7 while open cell won’t usually get much higher than R-4. Based on R-value, closed cell foam does a better job of keeping warm air inside during winter, and Australia’s hot air out in summer.

It’s important to understand though, that R-value isn’t the only consideration. Open cell has its own benefits which may appeal, depending on the job.

Do they expand differently?

Open and closed cell spray foam expand in a much different way. You’ll find that the expansion rate of open cell foam is much higher than closed cell. This makes open cell useful in hard-to-reach places like wall cavities. Its rapid expansion also makes it a useful low-cost option for those on a budget.

Closed cell foam may only expand to a third of the thickness that open cell does. This means it is possible to spray two or even three layers of foam, a useful strategy for increasing the R-value even higher.

Are they both water permeable?

Open cell foam is permeable to water. The amount that gets through will vary by product. Closed cell foam doesn’t allow any water through as it is 100% moisture impermeable.

Which is best for reducing noise levels?

Insulation is useful for dampening sound levels. If this is an important criterion for your project, then you may want to consider open cell foam. It is a much thicker material that does a better job of keeping noise out (or in).

Cost considerations

Pricing an insulation job can get a little complicated, as each one is unique. However, insulating with open cell foam will work out cheaper than closed cell. To discuss costs, get in contact as we’re happy to provide an obligation-free quote for your project.

Should I use open or closed cell foam insulation? 

As you can see, there is a range of factors to consider when deciding which type of foam is best for your needs. Open cell foam is a super-handy option for getting into challenging areas that are hard to reach. It’s also a good low-cost option for those on a budget.

Closed cell foam does a better job of insulating thanks to its superior R-value. It is rigid, providing added support to the structure, and it’s much better at keeping water out.

We’ve touched on some of the main differences between open and closed cell spray foam. With so many considerations, we recommend consulting a professional to ensure you get the best insulation for your project. Contact us today to get started.