Cool roofs-the metal roofing option

It’s roof replacement time— what type of roof is long-lasting and will keep my house cooler in the summer?—Randall

The two most common roofing materials for houses are asphalt/fiberglass shingles and metal. White shingles can be fairly energy efficient and can effectively reflect much of the sun’s heat. 

Standard black asphalt shingle roofing is probably the worst option, since the color absorbs much of the sun’s heat. This makes your house hotter, increases air conditioning costs and degrades the shingle material itself.

Joe Knife of Classic Metal Roofing Systems of Kentuckiana says, “After switching from an asphalt roof to a metal roof, most of my customers report a comfort difference. ‘We notice the house is cooler, especially upstairs,’ is what I usually hear.” Some report summertime savings of 17-23% on their energy bills, he adds.

Energy cost savings, however, depend upon several factors: the solar reflective value of the product, climate, insulation in attic/roof, energy prices, the slope of the roof, and the efficiency of heating and cooling systems.

Comparing roofing materials

Metal roofing can cost, on average, about double that of low-end shingles, but take into account that many types have lifetime warranties.

Aluminum and steel are the two most commonly used residential roofing metals. Copper is attractive and durable, but expensive and the patina does not reflect the sun’s heat well. 

Aluminum is an efficient material because the underside of the panels is bare and never rusts. It stops heat from radiating down into the house.

Painted steel roofs are also available in many colors and simulated contours. The steel is corrosion-resistant, so rust is not a problem. 

Old shingles typically have to be torn off before new asphalt shingles are installed, but metal roofs usually can be installed over existing shingles, which saves in labor cost and landfill space. Plus, aluminum roofing is often made of recycled content.

For more information, download the free Residential Metal Roofing Buyer’s Guide.

JAMES DULLEY is a nationally syndicated columnist who writes on energy efficiency and do-it-yourself energy topics.