What is Floor Insulation?

Mary McMahon
Mary McMahon

Floor insulation is insulation which is installed in a floor. Installing floor installation can cut down on energy costs, make a home more efficient, and contribute to the longevity of a home. While not ideal for every setting, insulation in flooring can sometimes make a big difference. Numerous materials can be used in floor insulation, including layered materials such as reflective foil to bounce heat back into a home, backed with fiberglass insulation to keep the floor insulated from temperature exchanges.


Historically, floors were not insulated under the argument that heat rises, so people should concentrate their energy on preventing heat loss through ceilings and walls which can occur as hot air moves upward through a home. However, heat loss through flooring can still occur when the area under the floor is not climate controlled. Thus, neglecting to insulate a floor can contribute to higher energy bills because heating systems will need to work harder to keep the space warm.

A floor is a good candidate for insulation if the space below is not heated and is fully vented. Creating insulation between heated spaces, as for example between a finished basement and a house, does not make sense unless people are concerned about noise control. Insulating a poorly vented space can trap moisture in and under the floor, which can damage the house. Likewise, if the area under the floor is wet, it needs to be equipped with proper drainage before floor insulation is installed, or moisture could become a problem.

Floor insulation can be blown in to some types of flooring, or installed manually, in the form of batting. There are a number of approaches which can be used, depending on the flooring. People who would like to insulate their floors should talk to a contractor about insulation options, and ask the contractor to assess their home to make sure that floor insulation is a sensible choice.

One thing to think about with floor insulation is that while warm floors can increase comfort in a home, the cost of insulating a floor properly may outweigh the costs associated with a less efficient home. Small savings may not be worth it, unless people simply dislike the idea of wasted energy, or find cold floors especially frustrating and uncomfortable. An energy audit can be performed to determine how much floor insulation would save in energy costs, and to identify other areas where savings might be found.

Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a wiseGEEK researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

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Discussion Comments


How long will it take me to install an insulated floor in my house?


I recently had an energy audit done on my home. I don't currently have insulation under my floors, since my home was built before it was common. Fortunately, the auditor found that the space under my house is really stable and doesn't allow a lot of drafts.

The extra cost to insulate my floors would have been in the thousands, but my savings would have probably been less than $100 a year, so I chose not to do it.


@jcraig - Like the article mentions, there are several types of flooring insulation you can choose. Fiberglass rolls are probably the most popular because almost anyone can install them. You could also go with rigid insulation panels or blown insulation.

As I'm sure you probably know, insulation is rated using an r-value, which is a measure of an insulation's effectiveness. If you look on the Energy Star website, they have recommendations for what r-value of insulation you will probably need based on your location.

I know that when you install a hardwood floor, you have to lay down a layer of moisture resistant material that may have some insulating properties. Unless there is some special material, I think most types of insulation would make the floor uneven unless they were installed under the subfloor.


What is the best type of insulation to use if you want to install insulation under a pre-existing floor?

I have done a little bit of research online, and most places mention using rolls of fiberglass batting. Are there any potentially better options? Also, what specifications should I look for when I am buying the insulation?

Out of curiosity, are there any types of hardwood flooring or carpeting that come with some type of insulating material already applied? It seems like that might be a popular idea.


We just installed hardwood floors in our home and chose to have insulation installed so that we didn't have to worry about the floor being cold.

The space under our house isn't completely open to the outside, but we have a space under our porch that probably makes the space more drafty. In our kitchen and bathroom where we have tile, we have noticed it can get cold in the winter, which is what sparked our decision.

Hopefully the new insulation will get rid of the problem with cold feet. This winter we should be able to tell whether or not the insulation has done anything to improve the heating bill.

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