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Energy Efficiency of Metal

Energy efficiency not only keeps your house cooler, but it keeps your utility bills down. A cool roof can make one of the biggest impacts to your energy use while providing you with a roof that can last 50 years or more.

Metal roofing materials have become more popular in recent years because of their durability and cost effectiveness. If you live in a hail-prone area, you probably have a big deductible to pay if your roof must be replaced. Not only is it less likely to sustain damage, a metal roof is more cost effective and lighter-weight than asphalt or other traditional roofing materials.

By choosing a cool metal roof, your return on investment is quicker and the energy savings will last for the life of the roof.

What is A Cool Roof?

A cool roof is one that helps keep temperatures lower and more stable inside the structure it sits atop. It’s typically a white or very light color and is designed to reflect the sun’s heat away from the building rather than absorbing and storing heat.

In tech-speak, a cool roof has relatively high solar reflectance and high thermal emittance.

Metal roofs are especially good choices for this because metal absorbs very little heat and releases what it does store very quickly. Asphalt roofs, regardless of their color, tend to soak up the heat. The heat builds up rather than being released right away, meaning whatever is below the roof becomes rather warm as well.

Cool metal roofs have other ways of keeping things comfortable. Besides the light color, the protective coating on the metal panels can include a variety of reflective materials to enhance the deflection of the sun’s rays. Coatings with the highest reflectance and emittance can reflect up to 90% of absorbed solar radiation.

The Relationship Between Cool Roofs, Energy Star & LEED Ratings

The EPA has a program called Energy Star® that can be applied to more than just appliances. Cool roofs can be Energy Star rated as well. To earn an Energy Star label, the roof must be considered a cool roof and help reduce heat-island effects.

  • Steep-slope roofs, 2:12 pitch or greater, must have an initial, newly installed, minimum solar reflectance of 0.25 and after three years a minimum of 0.15.
  • Low slope roofs, below 2:12 pitch, must initially have a minimum solar reflectance of 0.65 and, after three years, 0.50.

LEED certification is another way to determine the energy efficiency of a structure. LEED stands for Leadership in Energy and Environmental Design and the certifications are administered by the Green Building Council.

Designers and builders are awarded points toward a LEED certification when they use specified materials and designs that meet a particular Solar Reflectance Index (SRI). A cool roof is one such material. It not only earns a point for its energy efficiency, steel roofs are also sustainable and recyclable.

LEED requires a minimum SRI of 29 for a steep slope roof and a minimum SRI of 78 for a low slope roof. In addition, the cool roof must cover at least 75% of the roof surface area disregarding skylights, parapets and equipment.

Benefits of A Cool Roof

You have already read about a few such as increased solar reflectance and emittance, decreased energy use and eligibility for environmental certifications, but there are a few more.


A majority of metal roofs are made of steel and steel is a highly sustainable material. It’s sustainable because it can be 100% recycled and be made of as much as 95% recycled material. Steel is the most recycled material in the world and when it’s used to create new steel, it takes only a quarter of the energy required for “virgin” steel, made from extracted natural material such as iron.

Discounts, Savings & Other Incentives

Selecting a metal roof can get you a discount on your insurance. This is less due to the “cool” factor and more due to the durability and fire resistance of metal. In addition to savings on insurance, your utility bills can be cut by up to 40% annually.

A metal roof can also make you eligible for tax credits. For 2016, you can earn a $500 tax credit for installing a cool metal roof to your primary residence.


Metal roofs don’t have to be steel or aluminum colored nor do they need to look like corrugated tin. White and light colors are definitely needed for higher solar reflectance but the roof can be any color you desire. Manufacturers can create the exact shade you need.

Not only that, metal roofing materials can be formed to look like anything, including a traditional asphalt or shake roof. Other configurations include a style called “standing seam” in which the edge of each roof panel is bent upwards at 90 degrees and sealed to the adjacent panel. This configuration is perfect for installing solar panels and it sheds water extremely well.


Installing a metal roof requires specialized skills and not every roofing pro can handle this material. You need to find out if the pro you are hiring has the expertise to replace your old roof with a metal one or as the initial installation on a new home.

Not only does the company doing the installation need to be well-versed in handling metal roofing materials, but they should be knowledgeable about the local codes and standards covering metal roofs in your region. Because of its light weight, a metal roof can be installed right on top of shingles if needed.


Increased awareness of the environmental impact of structures has led to new policies and initiatives to promote green living. As energy bills continue to rise, a cool metal roof should be a definite consideration for your home.