Most Efficient Roofing Systems for Homes: How Much They Cost

The roof design is fundamental for an energy efficient home. You can have the most efficient air conditioning and space heating equipment in the market, but they will still waste energy if your roofing material is not an effective thermal barrier.

• A roof that is constantly absorbing heat in summer leads to higher air conditioning costs.
• A roof that loses too much heat during winter will drive up your heating and home maintenance costs.

To be energy efficient, a roof must accomplish two main functions. It must have a surface that reflects as much sunlight as possible away from your home, since this reduces heat gain during summer.

Your roof also needs adequate insulation, since this helps you save on HVAC costs all year long. Insulation reduces both summer heat gain and winter heat loss.

You can go one step further: there are now roofs with built-in solar cells, which means they can generate electricity all year long. In this scenario, the roof is not only acting as a thermal barrier for your home, but also as an onsite power generator.

As you can see in the monthly Consumer Price Index data, US electricity prices were up by more than 14% last year. Consequently, home solar systems have become more valuable since the electricity they generate is now worth more.

Here we will discuss three of the most efficient roofing options for homes:

• Roof shingles with Cool Roof Rating Council (CRRC) and/or ENERGY STAR rating.
• Metal roofs with CRRC and/or ENERGY STAR rating.
• GAF Timberline Solar Shingles

What Is an Energy Efficient Roof? Understanding CRRC and Energy Star Ratings

Any manufacturer can claim energy efficiency, even when their product offers standard performance. Third-party certifications are useful when purchasing energy efficient products, since they demonstrate that the product has been tested successfully by a recognized organization who is not controlled by specific manufacturers. This applies for roofing products, and there are two certifications you can look for:

• Cool Roof Rating Council (CRRC)
• ENERGY STAR, managed by the US Environmental Protection Agency

CRRC and ENERGY STAR are not mutually exclusive, which means the same roofing product can have both certifications. These labels tell you that a roof meets a set of energy performance requirements, but there are important differences between them.

CRRC Rating Requirements for Roofing Products

The Cool Roof Rating Council provides detailed requirements for roofing products in the CRRC-1 Product Rating Program Manual. This 74-document provides technical specifications that cover many aspects of roofing products, and the CRRC also has a product directory where you can filter roofing materials by manufacturer and performance features.

Other than meeting the Program Manual requirements, roofing manufacturers must also become CRRC Licensees before their products can be rated.

• Licensee fees are determined based on the sales volume of each manufacturer.
• There are also specific product rating fees, depending on the type of product being submitted for CRRC rating. There is an upfront fee and annual renewal fees.
• For example, standard roofing products have an initial fee of $250 and a renewal fee of $150 per year. These fees are also paid by manufacturers.

The CRRC defines a “cool roof” as one that uses sunlight-reflecting colors to minimize heat gain. Since some heat gain is unavoidable even with a highly reflective surface, a cool roof must also be capable of effective heat dissipation.

In other words, a cool roof reflects most of the sunlight reaching its surface, and the fraction of solar radiation that gets absorbed as heat is also dissipated efficiently.

Roofing products that are submitted to the CRRC are tested at Accredited Independent Testing Laboratories (AITL). The laboratory tests focus on two main performance aspects: solar reflectance and thermal emittance.

After the initial tests, roofing products are sent to CRRC Approved Test Farms, where they are subject to a three-year outdoor weathering test.

Manufacturers can pay an additional fee to get a rapid aging test under laboratory conditions, so they can get a temporary label while the three-year field test is completed.

• The performance of cool roofs has been studied by Lawrence Berkeley National Laboratory. They found that a gray roof reflecting only 20% of sunlight is 50°F hotter than a white roof reflecting 80%, assuming the comparison is made on a hot summer afternoon.
• The CRRC has also found that air conditioning costs are decreased by around 7-15% in homes with cool roofs.

You can find CRRC rated products of all types: asphalt shingles, asphaltic membranes, coatings, liquid-applied roof coverings, foam, metals, polymers/composites, single-ply membranes, stone/rock, tiles, and wood.

Keep in mind that the CRRC rating is not currently available for ballasted roofs and garden roofs.

ENERGY STAR Certification Requirements for Roofing Products

The ENERGY STAR program also has a technical guidance document for roofing products. The requirements are different for low-slope and steep-slope roofs, and they are summarized in the following table:

The US Department of Energy has estimated that ENERGY STAR roofs achieve typical lifetime savings of $0.64 per square foot. Considering that the typical US home has a 1,700 sq.ft. area, an ENERGY STAR roof can yield $1,088 in passive savings over time.

CRRC Rated Roof Shingles: Cost, Pros and Cons

Based on industry data, RoofingCalc has determined that metal shingle roofs have a typical price range of $10.50 – $15.50 per square foot. Assuming you install a 1,700 sq.ft. roof, you can expect to pay between $17,850 and $26,350 based on this cost range.

Asphalt shingle roofs have a much lower price, ranging from $4.50 – $8.50 per square foot, but they are also less durable. In this case, the total price for a 1,700 sq.ft. roof can range from $7,650 to $14,450.

You can find both metal shingles and asphalt shingles in the CRRC product database, but metal roofs offer higher solar reflectance values.

• As of April 2023, CRRC rated asphalt shingles offer a solar reflectance of up to 0.34, while CRRC rated metal roofs reach up to 0.77.
• In other words, metal roofs can cost twice as much compared with asphalt roofs, but they also reflect twice as much sunlight.
• A steel roof can last more than 50 years, while asphalt roofs typically last 15-25 years. You pay more upfront for a steel roof, but it saves you 1-3 asphalt roof replacements during its long service life.

Metal shingles are recommended if you want an ENERGY STAR roof, since there are many options that exceed the minimum solar reflectance requirement of 0.65.

Asphalt shingles with a solar reflectance of at least 0.25 can qualify for ENERGY STAR if they are designed for steep-slope applications, but they fall below the minimum requirement for low-slope roofs.

Many homeowners prefer the traditional look of asphalt shingles, compared with the more modern appearance of metal roofs.

But you can now find a wide variety of metal shingles in multiple colors. Many of them are designed to mimic traditional asphalt shingles while offering the advantages of a metal roof.

Did you know? Steel roofs are unaffected by mold and termites, which are common issues when using organic roofing materials like cedar. Asphalt roofs are unaffected by termites, but they can have moss and mildew issues.

Standing Seam Metal Roofs: Cost, Pros and Cons

These roofs are characterized by their simple design: instead of being composed of multiple shingles, they use metal sheets held together by seams. According to RoofingCalc, you can expect to pay between $12.50 and $21.50 per square foot, which is equivalent to a price range of $21,250 – $36,550 if you consider a typical 1,700 sq.ft. roof.

• A standing seam metal roof is an excellent option if you’re considering solar panels, since they can be clamped directly to the seams with no drilling involved.
• When you have a shingled roof, solar installers must remove individual shingles to access the roof structure and attach penetrating mounts.

The main downside of a standing seam metal roof is the high upfront cost, but you’re getting durability and energy efficiency in return.

Metal roofs can last for many decades, and you can find many options that are both CRRC Rated and ENERGY STAR Certified. Finding this combination is difficult when using other roofing materials that reflect less sunlight compared with metals.

Standing seam metal roofs have another disadvantage that is more subjective: since these roofs are composed of large metal sheets or pans instead of traditional shingles, so their appearance can seem “too industrial” for some homeowners. However, this is a matter of personal preferences and not a technical issue.

GAF Timberline Solar Energy Shingles: Cost, Pros and Cons

GAF has been a provider of roofing products for more than 100 years, and the GAF Energy business unit was created in 2019. Their Timberline solar energy shingles accomplish two functions, being both a roofing product and a solar generation system. These are the first nailable solar shingles in the market, which makes them easy to install with a nail gun.

• The traditional GAF Timberline shingle (without solar cells) was first introduced in 1967, and the product is currently featured in the CRRC directory.
• The new Timberline Solar product line enhances the performance of GAF roofs, bringing the ability to generate electricity. Each solar shingle has a rated output of 45 watts, which means 8-10 of them are equivalent to a high-performance solar panel.
• Timberline solar shingles are designed for roofs with a slope of 2:12 or higher.
• Four roofing colors are available: Birchwood, Charcoal, Pewter Gray and Weathered Wood

The GAF Energy solar roof is a relatively new product, launched early in 2022, and the company website does not provide official pricing information. Their CEO Martin DeBono quoted a typical price of $42,000 in an interview, but he mentioned it can be reduced to around $30,000 thanks to solar energy incentives. EnergySage reports a typical price of $4.80 per watt of solar generation capacity.

The main disadvantage of the GAF Timberline solar shingles is not being able to purchase them as a stand-alone product. You can only purchase them as part of a complete roof installation, and they cannot be combined with roofing materials from other manufacturers.

Purchasing a completely new roof with built-in solar shingles makes sense in new constructions, or if you have an old roof that needs a replacement soon. However, if your current roof is in good condition, the price tag of $42,000 is very high – for comparison, a 6-kW solar panel system can cost you around $18,000, before subtracting tax credits and other incentives.

Energy Efficient Roofing Systems: Final Comparison

The following table summarizes the main points covered above, comparing the typical costs and performance features of each roofing option.