Are you in the market for a “cool” metal roof? And by cool, we don’t mean hip or with it in the vernacular sense of the word. We’re talking about roofs that are literally cool, temperature-wise. Well, there is such a thing, and it all comes from the reflectivity of metal materials used to make what is known as cool roofs.
What Makes Vool Metal Roofs Cool?
Cool metal roofs provide excellent energy efficiency due to their high solar reflectivity. This, of course, translates into lower utility bills for homeowners living in houses equipped with this type of roof. This reflectivity of metal materials used to construct cool roofs is measured by albedos and is expressed in percentages.
When the reflectivity of metal materials used in a roof is high, it has a high percentage of albedos; conversely, when these materials do not reflect much of the sun’s light, the albedo percentage is considered low.
Reflecting the Heat of the Sun
But just because a roof is made from metal does not automatically make is highly reflective. Sometimes the reflectivity of metal materials used to make roofs is low. For example, the reflectivity in a metal roof painted white would be high, while an unpainted metal roof’s reflectivity would be considered comparatively low. The unpainted metal actually absorbs more heat than it reflects and is considered to be a warm roof.
Roofs constructed from asphalt shingles are considered hot. This is because emissivity also plays a role in heat retention and reflectivity.
While an unpainted metal does not reflect heat as well as one painted white, it emits heat faster than does a roof made of asphalt shingles, which not only absorbs heat, but also is slow in releasing or emitting it.
Labeling & Darker Colors Soon to Come
Soon the emissivity and reflectivity of metal materials will be indicated on the products for roofing. Several organizations, including the Cool Metal Roofing Coalition and the Cool Roof Rating Council, advocate these ratings so that when people search for the highest albedo rating on a roofing material product, it will be listed right on the label or packaging.
In the meantime, manufacturers involved with the reflectivity of metal materials are staying ahead of the game. New infrared reflective pigments are being incorporated into metal roof coatings so that darker colors can be used and still maintain high reflectivity ratings. This will give consumers a much wider choice of colors while enabling them to continue to save on cooling costs.
Now that we know how important the reflectivity of metal materials is to our energy savings, it’s good to know the technology exists to produce and enhance it. It’s also useful knowing that its ability to work for us in our everyday use is imminent.
So if you’re looking for an attractive, energy-saving alternative to traditional roofing materials such as asphalt shingles, wood shingles, etc., take another look at cool metal roofs. It’s another very good thing not only for our pocketbooks, but for our environment as well.