What is polyurethane’s energy efficiency per inch?

In terms of thermal resistance per inch, polyurethane is the most efficient insulation product available on the market. Indeed, its thermal resistance is the highest with an R value of R6 to R7 per inch.

The table below shows the average thermal resistance values ​​for a variety of insulation products.

RSI / Inch
Polyurethane 6.4 1.13
StyforoamTM Panels  5.3 0.93
ISOFOIL Panels 5.25 0.92
Cellulose 3.7 0.65
Wool mat 3.5 0.62
Fiberglass insulation 2.7 0.48


The place to be isolated and the budget will help determine the best insulation to choose from. For example, there is more space in an attic than in a wall to install a product that will be thicker to achieve the same R rating.