Insulating Resistance Value Fact: Cedar shakes and shingles have superior insulating value to other roofing products, keeping homes cooler in summer and warmer in winter. During infrared heat tests conducted at the University of Texas at Arlington, cedar shingle roofs kept ventilated attic spaces 26°F cooler than asphalt shingles. The Federal Housing Administration reports the "R-value" of cedar shingles to be double that of asphalt shingles, 4½ times that of fiber-cement shingles, and 18 times better than slate.