Is R value relevant?17 February
R-Value has long been part of the building and construction industry as the measure of thermal performance of a structure. It is generally accepted that higher R-Value equates to more efficient building insulation. Spray Polyurethane Foam (SPF) has changed some of the most common beliefs associated with R-Value.
To start, a couple definitions:
Conduction: transfer of thermal energy between neighboring molecules in a solid substance such as insulation.
Convection: movement of air molecules through insulation which carry heat energy outside the building envelope.
R-Value is a measure of a material’s resistance to heat transfer.
Conduction typically accounts for 20% of a building’s heat loss, while convection accounts for up to 80% of the energy loss depending on the quality of construction. Any convective loops inside the insulation material are taken into consideration by the R-value test method, but air leakage through the entire composite building envelope is not considered at all. Closed cell spray foam at ¼” can stop 80% of heat loss by convection and at 3″ will prevent 95% of heat loss by conduction. Obviously, the same holds true for an air-conditioned structure.
Common Questions:
“The higher the R-Value the better, correct?”
Yes, higher R-Value in your home or building is somewhat better; however, its importance is overemphasized. SPF’s ability to create an air-tight seal for your home is the most important factor in creating an energy-efficient, comfortable, and healthy home. About 80% of the energy loss of your home or building is caused by unwanted and uncontrolled air flow through the walls, ceilings and floors.
“What is the R-Value of your product?”
R-Values vary by manufacturer. EcoLogic is proud to provide its Soy based, spray foam system which provides an R Value of over 6 per inch of depth.
Air tight seal
Closed cell Spray Polyurethane Foam offers higher R-Values per inch than conventional insulating alternatives. Most importantly, only spray foam provides total air tightness. As a matter of fact, just 2 inches (5 cm) of closed-cell foam provides a vapor barrier. No other insulation system can provide that! When considering your insulation choices, the air-tightness alone should be a compelling reason to insulate with SPF.
Tags : air tight, conduction, convection, efficiency, energy efficient, heat loss, R-value, spray foam insulation, thermal insulation
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