How a Metal Roof Affects Your Energy Use

People ask whether a metal roof will lower their electric bill. Sometimes, a little, and it helps to know why so you do not expect more than it can deliver.

Three things are doing the work. The paint: the PVDF coatings we use reflect a good share of the sun's energy instead of soaking it up the way a dark asphalt shingle does. The metallic layer under the paint, which is mostly aluminum, re-emits heat rather than holding it. And ventilation, which matters more than either: air comes in at the soffit and leaves at the ridge, and that keeps the attic closer to the outdoor temperature. A metal roof on an attic with no airflow is still a hot attic.

Here's the tradeoff. The savings are real in summer and smaller in winter, and they depend on your insulation and ventilation as much as the roof. If the reason you are considering metal is energy alone, run the numbers first. If you are already leaning toward a long-term roof, this is a point in its favor, not the reason to buy. Now you have the context to weigh it.