Heat gain through the roof or attic is about 15-25% of the heat gain for the entire building (ORNL 2022). This heat gain can be reduced by using “cool” white or reflective roofing materials as described in the guide Cool Roofs and Walls, by using a radiant barrier as described in the guide Attic Radiant Barriers, by providing shading as described in the guide Landscaping to Reduce Cooling Load, and by adequately air sealing, insulating, and venting the attic. There are several guides in the Solution Center that describe effective ways to air seal, insulate, and ventilate new and existing homes.
Attic Air Sealing
Guides describing ways to air seal attics and ceilings in new homes include the following guides for the whole attic and specific components within the attic or penetrations through the attic floor:
Guides for air sealing attics and components within the attic in existing homes as a retrofit measure include the following:
Guides for insulating attics in new homes include the following:
Guides for insulating attics in existing homes as a retrofit measure include the following:
Guides describing ways to ventilate attics and roofs include the following:
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The following authors and organizations contributed to the content in this Guide.
Pacific Northwest National Laboratory