Whether you want to lower your energy bills, qualify for tax savings, reduce your carbon footprint, or all of the above, energy-efficient roofing offers a three-in-one solution.
Energy-efficient, or “cool roofing,” involves exterior materials, as in what goes on the outside of a building, as well as interior components like insulation and ventilation.
To learn how you can save money in the long term with cool roofing, check out our list of the seven most energy-efficient options.
What is energy-efficient roofing?
Any roofing system that reduces the energy consumption of the structure beneath can count as a form of energy-efficient roof.
The materials
Intuitively, the roofing material plays a vital role in energy efficiency.
Along with siding and windows, your roof captures direct sunlight, which is why buildings heat up during the day.
Roofing materials that reflect the sun's rays and emit heat back into the atmosphere hinders the increase of internal building temperatures. With a more comfortable building, occupants can put less demand on air conditioning, which leads to lower energy bills.
To calculate energy efficiency, the industry uses the Solar Reflectance Index, which combines both the reflective and emissive qualities of a material into a single number between 0 and 100. A higher SRI number indicates better cooling performance.
What SRI number qualifies as energy-efficient?
Whether a roofing material meets the definition of energy-efficient depends on who you ask and the roof slope.
For example, LEED only offers credits for pitched roofing materials with at least 39 SRI at installation and 32 SRI after three years in place.
If you live in Los Angeles, the local Green Building Code requires steep-sloped materials to equal 16 SRI at a minimum.
Each of these standards designates stricter requirements for low-pitched roofs (roofs with less than or equal to 2:12 rise to run).
Interested to know the SRI of a particular roofing material? The Cool Roof Rating Council hosts a directory detailing the radiative qualities of thousands of roofing products.
Table of energy-efficient roofing standards (in SRI)
|
Source |
Pitched roof |
Pitched roof (after three years) |
|
Energy Star |
25 |
15 |
|
LEED |
39 |
32 |
|
Los Angeles Green Building Code |
16 |
N/A |
The 7 best energy-efficient roofing options
Insulation
Image source: Roof Doctor
Without even touching your roof, you can cut up to 10 percent of your energy costs with home insulation.
Insulation works two-fold to improve building energy efficiency.
Following suit with exterior materials, roof deck insulation stops outside temperatures from penetrating your attic space.
Insulation also prevents costly, air-conditioned, or heated air from escaping your home, which further reduces the need to keep your HVAC system cranked.
Depending on the project scale and insulation material used, prices can range from a few hundred to a few thousand dollars.
Insulating your roof and attic should run far less than the average roof replacement cost.
If you want to lower your energy bills without paying for a new roof, insulation presents a cost-effective start.
Cool roof coatings
Image source: Roofing Contractor
If you live in a hot climate and your existing roof still has plenty of life to give, a cool roof coating saves you the trouble of an outright replacement while reducing up to 30 percent of cooling costs.
These white, reflective coatings maximize the roof's ability to reflect and emit heat.
For sloped roofs, the bright white color arguably compromises curb appeal in most cases, which is why cool roof coatings better suit low-sloped roofs.
Cool roof coatings typically cost between $0.75 and $1.50 per square foot.
Considering a flat roof replacement costs as much as $42 per square foot, cool roof coatings propose an affordable approach to improving roof energy efficiency for flat-roofed buildings.
Asphalt shingle roofing
Image source: Owens Corning
When infused with reflective granules, asphalt shingles can boast respectable SRI ratings and even qualify for energy efficiency standards, all at an unbeatable price.
Cool roof shingles cost around $5 to $13.50 per square foot, making them the most affordable energy-efficient roofing material in most cases.
However, most shingles do not feature these coated granules. Keep an eye out for products that include them or meet energy efficiency standards.
Owens Corning, for instance, indicates their energy-efficient shingles with the COOL moniker. At best, their Duration COOL architectural shingles boast 29 SRI – above Energy Star standards!
Metal roofing
Image source: Metal Roofing Alliance
Metal roofing comes in many shapes (panels, tiles, shakes), substrates (steel, aluminum, copper), and colors to suit both residential and commercial buildings, but one aspect is almost certain – energy savings.
Lighter colors and vented metal roofing installation can net energy savings of up to 25 percent.
Beyond its energy-saving capabilities, metal has earned a reputation as one of the most sustainable roofing materials thanks to industry recycling efforts. Many manufacturers even include recycled material in their new metal roofing products.
Of course, a metal roof will cost more than an asphalt roof at around $4 to $40 per square foot.
However, the energy savings and enduring lifespan, 80 years in ideal cases, will recoup your costs and then some.
Tile roofing
Image source: Dynasty Building Solutions
Tile roofing fosters energy efficiency mainly by the nature of its installation, which researchers found can lower annual air conditioning costs by as much as 20 percent in the intense Southern California heat.
Image source: Roofing Magazine
As roofing tiles overlap with each course, channels form above the roof deck that allows air circulation. These air channels perform as both another layer of insulation and an avenue for hot air to circulate out before penetrating the building envelope.
Concrete and clay – the primary materials used to make roofing tiles – also boast inherently high thermal emittance values, which leads to impressive SRI figures.
Tiles do not suit every homeowner, however. Among the cons of tile roofing, they cost around $7 to $41 per square foot – more than twice the cheapest asphalt shingle roof products.
Still, the visual appeal of a tile roof outweighs the costs for many homeowners, as should the energy efficiency.
Solar tile roofing
Image source: Tesla
The only thing better than a roof that lowers energy costs generates energy itself!
Like conventional solar panels, solar tiles come equipped with photovoltaic cells that convert sunlight into electricity.
Unlike arguably unsightly solar panels, they embody the elegant profile of traditional tile or shingle roofs. Solar tiles endow you with the savings of renewable energy without compromising on style.
Perhaps unsurprisingly, solar tiles are not cheap relative to non-solar roofing materials. Tesla, the most popular solar tile provider, charges about $1.80 per watt without taking accessory equipment into account.
Despite the hefty upfront costs, solar tiles should pay for themselves within a decade through energy savings and solar incentives.
Green roofing
Image source: Buildings
When it comes to sustainability, perhaps no other roofing material comes close to green roofing.
Green roofs are essentially just soil and vegetation atop a flat roof.
This primitive combination dates back thousands of years as a roofing material. Nonetheless, modern-day sustainable urban developers gravitate towards green roofs because of how well they combat the urban heat island effect – the reason why cities clock hotter temperatures than outlying areas.
From an energy-efficiency standpoint, green roofs absorb solar radiation and provide insulation, which keeps the building more comfortable. One study found a reduction in air conditioning demand by more than 75 percent for a building with a green roof.
Beyond helping you save money, green roofs offer a long list of personal and communal benefits, including improved roof lifespan, stormwater retention, and natural beauty.
Green roof costs range between $10 to $35 per square foot. Potentially adding to lifetime costs, some green roof systems require frequent maintenance.
Cut your home energy bills by opting for an energy-efficient roof
Now that you know which roofing options can save you money in energy costs, it’s time to pick one.
Unfortunately, determining the best energy-efficient approach for your budget can often be the toughest part.