Question

Are metal roofs more energy efficient for southern climates than shingles?

Asked by Eliza Blues
West Palm Beach, FL

Are metal roofs more energy efficient for southern climates than shingles? Is a metal roof worth the extra money in terms of energy savings? I'm seeing a lot more people put metal roofs on here in Florida. I realize they're supposed to be better for hurricanes and they last longer. (The light-colored shingles will probably be more my price range though, which is good because I'd have a hard time choosing colors.)

Answer

Anthony Addesso

Answered by Anthony Addesso

Hawthorne, NJ

Addesso Architecture

October 20, 2010

Metal roofs definitely contribute to an energy efficient home.

  • In your area wind and hurricanes are a concern and metal roofs are more durable than shingles.
  • Most insurance companies are giving discounts for metal roofs because of their durability.

Another consideration is Solar Reflectance. The higher the Solar Reflectance index or SRI the greater the ability of the material to reflect the heat generated by solar radiation back into the atmosphere and not into the house.

  • A lighter color shingle roof will be better than a dark one by increasing the roof's ability to reflect heat from solar radiation. 
  • Fiberglass shingles hold the heat created by sunlight during the day long into the evening hours, transmitting the heat into the building and thus increasing your cooling requirements even after the sun has gone down.
  • A metal roof has a higher emissivity factor, by radiating the collected heat back into the atmosphere quickly.

To increase the energy efficiency of a home even more create a cool roof which keeps the roof and attic much cooler than asphalt or fiberglass shingles.

  • The metal is installed on a system that actually raises it above the roof deck itself creating an air space to allow the heated air to escape, and keep the transmission of heat to the house even lower.
  • The combination of the emittance and the higher SRI of the cool metal roof creates a roof that transmits much less heat into the building.

A metal roof is approximately 30% more expensive than a shingle roof, but there are metal roof solutions that rival high-end shingle roofs. The cost of energy will be going up in the near future and will most likely continue to go up, and generally with a cool roof versus a shingle roof you can see a reduction of cooling requirements by 30%, so in the long term, the increases, in addition to the energy savings and state and federal tax credits, should give you a fairly fast return on your investment.

 

For more information:

Read Mick Dalrymple's Q&A "What type of roof should I choose in a hot climate?"

Check our Find a Pro directory to find a green roofing professional near you.

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