What is the Most Energy Efficient Roofing Material?

When you start looking into roofing materials, you may be overwhelmed by the number of materials that are available for roofing your building.
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When you’re responsible for making the most out of your commercial space, you should consider one aspect of savings that many in your shoes don’t — energy efficient roofing. Energy efficient roofing is roofing that cuts down on the consumption of energy by the structure underneath, and “cool roofing”, as energy efficient roofing is often called, can have a surprising impact on your savings. The three-pronged effect you will see is lower energy bills, new tax savings, and less of a carbon footprint.

Utilizing the most modern roofing materials doesn’t limit you as to what type of roof you can build, but in actuality, it gives you more choices regarding the cost range and the aesthetics and features you are in the market for. What is the most energy efficient roofing material? Let’s examine some energy efficient roofing options and see what you think.

What Makes a Material "Energy Efficient"?

When you start looking into roofing materials, you may be overwhelmed by the number of materials that are available for roofing your building. They carry asphalt shingles; metal roofing; wood shakes; slate, solar, and clay and concrete tiles, and EPDM rubber. However, not all of these roofing choices are energy efficient.

Just as the sun, through your windows, heats up your home, your roof absorbs heat from direct sunlight which will do the same. However, if you can find a roofing material that reflects the sunlight back out away from your home, you can prevent this and keep your home cooler. This means less need for air-conditioning, thus, the term “energy efficient”.

What Is an SRI Rating?

An SRI rating is a way to rate the energy efficiency of roofing materials. Here’s the gist of it.

Solar Reference Index

In order to create a scale for energy efficiency, the US Department of Energy uses an SRI (Solar Reflectance Index). This number combines the reflective with the emissive qualities a material has into one number between zero and 100. The higher the SRI rating, the better energy efficiency a material has.

Entity and Roof Slope

Is the material that I want to use for my roof energy efficient? Well, that depends on which entity is answering the question.

Energy Star

ENERGY STAR® is a symbol showing that a product is energy efficient. Energy star is government-backed and provides information to consumers that’s unbiased, credible, and uncomplicated. Local, state, utility, commercial, and industrial organizations are partnered with the EPA (United States Environmental Protection Agency) to give consumers solutions that save them money and save their environment.

At first, steep-slope roofing materials must have an SRI rating of 25 to qualify as energy efficient or three years after installation, they must have an SRI of 15 to be certified.

LEED (Leadership in Energy and Environmental Design)

LEED (Leadership in Energy and Environmental Design) is used more than any other green building rating system worldwide. The best thing about it is that it applies to all types of buildings and all phases of building. The LEED symbol is recognized globally representing sustainability, health, cost-effectiveness, and high efficiency, as well as leadership.

Initially, at installation, pitched roofing materials must earn an SRI of 39 or greater, and three years after installation, they must have an SRI of at least 32.

CALGreen (California Green Building Code)

The California Green Building Code (CALGreen) was created to improve the safety, health, and general well-being of Californians through the enhanced design and the resulting construction of buildings. To accomplish this, CALGreen used concepts that cut down on the negative impact of building on the environment and promoted principles that instead had a positive impact on the same, encouraging sustainable construction practices.

In Los Angeles, CALGreen requires an SRI rating of at least 16 for steep-slope roofing materials.

Important Facts

  • The Cool Roof Rating Council website offers a directory of the radiative properties of roofing products. If you would like to know the SRI of the roofing material you are considering, you might want to check with them. Thousands of products are listed.
  • Whether Energy Star, LEED, or CALGreen, stricter requirements are designated for low-pitched roofs (roofs with a rise to run ratio of 2:12 or less).

What Are the Most Energy Efficient Roofing Materials?

When insulation and efficient ventilation isn’t enough, consider an energy efficient roof. A roof made of the right energy efficient material can go a long way toward not only saving you tons of cash but toward saving the environment, and after all, doing what’s really important — keeping you cool on those scorching hot summer days. Here is a list of the most energy efficient roofing materials.

"Cool Roof" Coatings

Better suited for low-sloped roofs because of aesthetics, these white reflective “cool roof” coatings deflect the sun’s heat away from your home. So, if your roof doesn’t need to be replaced, but it isn’t energy efficient, this may be just the ticket. You just apply this coating over the existing roof to cut up to 30% off cooling costs in warmer climates.

Cool roof coatings are estimated by the EPA to have an average cost of between $1 and $1.25 per square foot.

Metal Roofing

Metal roofing has many faces. It can be aluminum, copper, or steel and come in tiles, panels, or shakes. Plus, there is more than one color of metal available, so you can pick the perfect match for your commercial building. Of course, the lighter the color, the less heat it absorbs.

It doesn’t seem feasible, but metal roofing can be safely ventilated, and paired with a light-colored roof, it can save you 25% on your utility bill. Also, metal roofing is resilient and long-lasting. You can add on a metal roof and expect it to last for a minimum of 50, and in the best climates, over 75 years, probably the rest of your lifetime.

Metal is also recyclable, but it is a little more costly averaging $11.50 per square foot. Matching up the investment with the return, though, will tell you that metal roofing is a great energy efficient roofing option.

Asphalt Shingles

Containing granules that reflect heat, asphalt shingles have good SRI ratings. These shingles are the most affordable roofing material in the “energy efficient” class. Most roofing shingles on the market do not contain these reflective granules.

The average cost of asphalt shingles or “cool roof” shingles is $4.75 per square foot.

TPO Roofing

Thermoplastic polyolefin (TPO) roofing is the most popular type of synthetic roofing for flat roofs on commercial buildings. A TPO roof is energy efficient because its single-ply membrane reflects light and heat.

TPO roofing costs an average of $6.50 per square foot, but costs can vary widely from job to job.

Bitumen Roofing

Bitumen roofing sheets are also great for flat roofs on commercial buildings. These sheets are composed of a membrane that’s similar to plastic paired with asphalt. Bitumen insulates well from heat and cold.

Bitumen roofing has an average cost per square foot of $3.25.

Tile Roofing

Tile roofing encourages energy efficiency by the manner in which it is installed. The tiles are each installed individually, and they overlap in such a way as to provide insulation but still allow circulation, so it keeps the building below cool. Ceramic, concrete, and slate tiles are the best choices for energy efficient roofing tiles, chosen for their reflective properties. Concrete tile roofs can survive for 50 years while slate and ceramic tile roofs can survive up to 150 years if installed correctly.

There is much to consider when pondering the cost of tile roofing. First, you must consider the size and style of your roof and how many plumbing vent boots your roof has. Next, you should consider the area you live in and which tiles you’ll be using. Lastly, consider whether there is damage that has to be dealt with. Overall, for all tile roofing, you will pay between $8 and $25 per square foot, but know that you will pay more if you choose terracotta than if you choose concrete.

Green Roofing

Green roofing can be the ticket, especially in urban settings where it can get hotter than in most suburbs. Green roofing is a simple concept, it is essentially soil and vegetation enclosed on a flat roof. It may be a new idea to Americans, but the idea itself has been put to use for thousands of years. Green roofs insulate and absorb heat well.

In fact, one study showed green roofing reducing the need for air conditioning by over 75%. Green roofs cost an average of $15 per square foot.

Solar Roofing

So, lowering energy costs is great, but what if you could generate energy with your roof. Similar to solar panels, solar tiles are composed partly of photovoltaic cells which convert sunlight into electricity. They are dissimilar to solar panels, however, in that they are not aesthetically unpleasing to the eye but elegant and tasteful, similar to traditional tiles. They allow you energy efficiency and refinement.

Solar tiles are not inexpensive, though, at an average of $16.98 per square foot (just the tiles). However, they will save you that money back within about 10 years through energy savings and tax incentives.

Is There a Downside to Energy Efficient Roofing?

There’s not really a downside to energy efficient roofing. You benefit from energy efficient roofing by saving on utility bills, but that’s not the only upside. The value of the property (business) will rise, and new tax incentives will become available. Your roof will be longer-lasting and have lower maintenance, plus, you’ll be cooler in the heat of summer.

For the finest in Houston commercial roofing, contact Royal American Services for a Free Onsite Inspection. It would be our great pleasure to help you go green. Besides new roofing, we also do roof repair, leak repair, storm damage repair, and preventative maintenance. 

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