Insulants

Insulants are materials designed to restrict energy transfer, most often heat, though electrical insulants are used to prevent current flow. Thermal insulants reduce heat transfer through conduction, convection, and radiation, improving energy efficiency in buildings, refrigeration, and industrial processes. Electrical insulants are non-conductive and are used to separate energized parts and protect against electric shock.

Common thermal insulants include foams (such as polyurethane and polyiso), rigid boards (EPS, XPS, polyiso), fibrous materials (fiberglass, mineral wool), natural and recycled insulations (cellulose, wool, cotton), aerogels, and reflective foil barriers. These materials appear as boards, batts, rolls, sprays, or loose-fill forms. Performance is described mainly by thermal conductivity (k) and thermal resistance (R-value or RSI). Other important factors are density, moisture handling, fire rating, and long-term stability.

Applications span building envelopes (walls, roofs, floors), plumbing and HVAC pipes, refrigeration cabinets, and industrial equipment. Real-world performance depends on proper installation, airtightness, and minimizing thermal bridging, all of which influence whether rated performance is achieved.

Environmental and health considerations include embodied energy, the choice of blowing agents or refrigerants, potential impacts on climate, fire safety, and possible irritation from certain fibers. Some insulants are sensitive to moisture and require vapor barriers or appropriate ventilation strategies.

Standards and testing involve measuring thermal performance with methods such as ASTM C518 (or ISO equivalents), reporting RSI or R-values in different regions. Selection balances climate, moisture, fire codes, durability, and sustainability goals.