Glossary of Home Insulation Terms
R-Value
A measure of thermal resistance. Higher R-values indicate better insulating effectiveness, meaning the material provides greater resistance to heat flow.
Batt Insulation
Flexible, blanket-like sheets made from fiberglass or mineral wool, commonly used in walls, floors, and ceilings.
Blown-In Insulation
Loose-fill insulation made of fiberglass, cellulose, or mineral wool that’s blown into walls, attics, or other areas using special equipment.
A liquid foam that’s sprayed into place and expands to form a solid, air-sealing barrier. Available in both open-cell and closed-cell varieties.
Panels of foam that provide high insulating values, often used for foundation walls, roof decks, and exterior sheathing.
Thermal Bridging
Occurs when a material that is a poor insulator allows an easy pathway for heat flow across a thermal barrier. Common in areas where structural elements penetrate insulation.
Vapor Barrier
A material designed to prevent moisture from passing through walls, ceilings, and floors, which helps to control indoor humidity levels and prevent mold growth.
Air Sealing
Techniques and materials used to prevent unwanted air leakage in a home, improving energy efficiency and indoor comfort.
Energy Star Rating
A government-backed symbol for energy efficiency. Products that earn the Energy Star label meet energy efficiency guidelines set by the U.S. Environmental Protection Agency.
Continuous Insulation
Insulation that is uninterrupted by structural elements like studs or joists, providing a consistent thermal barrier across the entire building envelope.
U-Value
A measure of heat transfer through a building element such as a window, door, or wall. Lower U-values indicate better insulating properties.
Thermal Envelope
The shell of a building that separates the interior from the exterior environment, encompassing walls, floors, roofs, windows, and doors. Proper insulation of this envelope is key to energy efficiency.
Heat Flow
The transfer of thermal energy from a warmer area to a cooler one. Proper insulation helps to reduce heat flow, keeping indoor temperatures more consistent and comfortable.
A type of batt or blown-in insulation made of fine fibers of glass, providing good insulating properties and fire resistance.
Loose-fill insulation made from recycled paper products treated with fire retardants, offering good thermal performance and soundproofing qualities.