radiant heat flooring with insulation 1

Can I use AtticFoil® Radiant Barrier in my radiant heat flooring system?

Yes! If you are using radiant heat tubes under a floor, then you need a radiant barrier to direct the heat upward into the floor.

There are typically two different cases for radiant floors:

  • Over a conditioned space. Example: a finished basement 
  • Over a non-conditioned (or cold) space. Examples: over a non-heated basement or over a vented crawl space. 

The concept is really pretty simple. The tubes are attached to the bottom of the subfloor and they get hot from either hot water or glycol running through them. When the tubes get hot they act just like a hot light bulb. The heat wants to go both upward into the wood, and downward to the space below. However since the goal is to heat the floor above the tubes, we need to find a way to prevent heat loss to the room below the tubes.

A radiant barrier will act like a REFLECTOR (just like a mirror) and direct the heat that is going downward back UP towards the floor to make the radiant heating system more efficient.

For both methods, the installation is pretty much the same for the foil so the difference is whether or not you need to add traditional insulation.  

Is Radiant Barrier the only option?

There are other products that are made from aluminum fins which clip on the radiant tube. These products help carry the heat by conduction into the floor. These products are expensive compared to AtticFoil®, and there are usually gaps between the clips that allows the heat to radiant downward.

Additionally, once the floor gets warm, the whole floor wants to radiant heat both upward and downward. You do not want to lose the heat going downward, this is where a radiant barrier comes in:  a radiant barrier will reflect the radiant heat back upward. This is the same concept as an attic installed radiant barrier. The roof will get hot and we do not want the radiant heat to enter the attic. A radiant barrier installed in the attic will reflect heat upward towards the sky just like it will reflect the heat upward towards the floor in a radiant flooring application.

Installation

Just like the radiant heat flooring over a conditioned space installation, you will add the foil first.  The difference is that you will add the foil between the floor joists (the ceiling joists from the basement side), taking care to leave an air gap between the foil and the radiant tubing (this is similar to the Cathedral Ceiling installation method). Then, once you've achieved an air gap between the foil and the tubing, you will add insulation below the foil; this will give you a layered system.  The radiant barrier will reduce radiant heat loss and the traditional insulation will redice conductive heat loss.  Below the insulation you will usually want to finish it out with drywall or another product that will help hold the insulation in place and provide an air barrier for the insulation.

Installation Photos

flooring radiant heat pex tubes with insulation 1 flooring radiant heat pex tubes with insulation 2
In this application a foam strip is attached to the subfloor to ensure the air gap above the foil is not compromised when the insulation is added. It's not necessary, but it can help. The standard layers coming from the floor down should be subfloor, radiant heat tubing (Pex tubing), air gap, radiant barrier foil, and insulation.
flooring pex tubes and radiant barrier over conditioned space 1

Can I use AtticFoil® Radiant Barrier in my radiant heat flooring system?

Yes! If you are using radiant heat tubes under a floor, then you need a radiant barrier to direct the heat upward into the floor.

There are typically two different cases for radiant floors:

  • Over a conditioned space. Example: a finished basement 
  • Over a non-conditioned (or cold) space. Examples: over a non-heated basement or over a vented crawl space. 

The install methods are the same for the radiant barrier foil, however over a cold space you will also add traditional insulation to further reduce conductive heat loss.

Using radiant heat is a great method to heat a home. Putting heat into the floor produces a very comfortable source of heat. The challenge is how to most effectively get the heat from the tube into the floor without losing heat below the tubing, i.e. how to get the heat directed UPWARD rather than down into the space below.

Installation over Conditioned Spaces

This method is typically used in homes that have a heated basement. There is usually no visible insulation between the floor joists when looking up from inside the basement. With this setup, your main goal is to get the heat from the radiant heat tubes to go up into the floor above.

You will simpy staple the foil across the floor joists (the ceiling joists from the basement side) and your air gap will be between the radiant tubing and the foil on the bottom of the joists.  You will not need regular insulation since the floor is between two living spaces; this is similar to an interior wall assembly: since it is not part of the thermal envelope (the area you heat and cool) no insulation is needed, just a radiant barrier.

Installation Photos

flooring pex tube and radiant barrier 1 flooring pex tube and radiant barrier 2
In this approach, you install the foil so it droops down, creating an air gap between the pex tubing and the foil.  You adhere the foil by staping the outer edges to the bottom of the subfloor. Another method for installing foil under radiant heat flooring is to staple it to the sides of the floor joists, about 2" below the subfloor. 

2014 Closed for Thanksgiving 

All orders placed after 4pm CST on Wednesday, 11/26/14 will ship out Monday, December 1, 2014.

AtticFoil Radiant Barrier Supply, LLC, Insulation Contractors Equipment & Supplies, Argyle, TX

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