Polyurethane Foam Pipe Insulation Vs. Polyisocyanurate

Polyurethane Foam

• Polyurethane foam insulates and air-seals, and it is water resistant. For simplicity, it is referred to as SPF (spray polyurethane foam). Hot water loses heat as it sits in pipes between your water heater and your faucets. As a result, you have to keep the water running during the lag until it heats up again. SPF comes in aerosol-type can applications that you spray into gaps and crevices surrounding plumbing and pipes so they are airtight. Polyurethane foam has a relatively high R-value, which is the measurement used to rate insulation’s efficacy at preventing thermal heat loss. The R-value for polyurethane foam can be as high as 6.5 per square inch, and it is classified as a “closed cell” and Class II insulation material, meaning that it serves as an air barrier and vapor retardant.

Polyisocyanurate

• Polyisocyanurate (called “polyiso”) is a rigid foam-board insulation material that can be used in commercial, institutional and residential applications. It is classified as a closed-cell insulation and is composed of a foam core sandwiched between facer materials typically made from paper and fiberglass. In homes, polyiso is primarily used for roof and sidewall insulation. It has the highest R-value of all types of insulation and is often used in schools, hospitals and federal government buildings for roofing and sheathing insulation. When used for insulating walls in homes, polyiso increases energy efficiency, reduces air infiltration and exfiltration, thereby reducing heat loss, water condensation and moisture intrusion.

Similarities

• Polyurethane and polyisocyanurate create highly efficient air barriers, reduce moisture and condensation and improve the overall energy efficiency of homes and buildings. Both insulate rooms that house pipes and water-fueled appliances such as bathrooms, kitchens, laundry rooms and basements. Their ability to retard moisture and condensation help prevent the growth of mold and mildew, which adds to their efficacy and appropriateness as insulation materials for walls and surfaces where plumbing, pipes and water-related equipment, such as sinks, bathtubs, showers, and refrigerators, are located.

Differences

• Polyisocyanurate is only installed by trained professionals and is only sold to members of the construction and building trade. It is typically installed in residences during new constructions, although it is possible to retrofit existing homes with polyiso. Polyurethane foam, on the other hand, is commonly used on a do-it-yourself basis. It comes in small, 12- to 24-oz. spray cans and can be purchased at most home improvement stores. The ease of application makes polyurethane quite suitable for homeowners to use to insulate pipes and plumbing underneath kitchen and bathroom sinks, and around pipe connections for appliances such as washing machines, dishwashers and hot water heaters.