Therma-Dome Whole-House Attic Fan Cover

R-40 Fan Cover
R-40 Fan Cover

Each Kit Includes

  • Foil-Faced Fire-Rated Foam Panels
  • Integrated gasket and straps
  • Construction Adhesive
  • Foil Tape
  • Step-by-Step Instruction Sheet


Made in USA



A Whole-House Attic Fan can be a very efficient way to keep your home cool during certain times of the year.

However, when the fan is not being used, the fan opening can be a huge source of unwanted heat transfer between the living space of your home and the unconditioned attic space. In cooler months, this may result in heat loss that can lead to condensation and moisture damage in the attic, ice dams on the roof, and cold drafts in the living space below the fan. In the warmer months, especially during times of the year when air conditioning may be used in the home, you will have super-heated air from the attic pushing its way down into the living area of your house, adding to the work load of your air conditioning equipment to keep you comfortable.

The Therma-Dome Whole-House Attic Fan Cover is designed to be a seasonal or permanent cover for whole-house attic fans.

Therma-Dome products are Constructed of fire-rated (exposed-use) polyisocyanurate foam insulation board that is sandwiched between layers of laminated foil, this Therma-Dome product is designed to last as long as your home. The exterior-grade cellular foam core weatherstrip gasket provides a continuous air seal, stopping costly energy drain.

The use of a Therma-Dome cover can help conserve enough energy to pay for itself in just one year. (Energy cost savings may vary, depending on utility rates in your area.) The Therma-Dome cover is constructed of fire-rated material, meeting the most stringent state and local building code requirements.

The Therma-Dome Attic Stair Cover comes as an easily assembled kit, which includes six lap-joint components, a tube of adhesive, foil tape, and step-by-step instructions. Equipped with only a caulking gun and scissors or a utility knife, you can assemble and install this money saving cover in as little as fifteen minutes.

Product Specifications

Insulation Value

R-40 (or custom-made to spec)

Inside Dimensions

37″ Wide x 37″ Long x 16″ High (or custom-made to spec)

Outside Dimensions

43″ Wide x 43″ Long x 22¼” High (or custom-made to spec)


17 lbs. (varies with custom-made design)

Carton Weight

20 lbs. (varies with custom-made design)

Tools Required

Caulk Gun, Knife or Scissors