The R-value and its metric equivalent, the RSI value (Resistance System International - RSI = R x 0.176), are used to rate the effectiveness of insulation materials.
The higher the R or RSI value, the better a material resists to temperature variations. (Insulation products sold in Canada bear both R and RSI values.)
In the case of new buildings, the Québec Building Code specifies minimum R and RSI values, which vary depending on the region and the type of application.
When selected with care, insulation materials create an efficient building envelope and satisfy your desired level of comfort.
Some R-values per inch: