According to Steve Easley, a British Columbian building science consultant, many people don’t choose energy-efficient, cool roofs. This is because in the past these roofs were only available in white – something that’s changing today.
The military has conducted research that’s enabled manufacturers to create a formula for treating shingle-topping granules. This means that darker colors including forest green, brown, and black are now options. They can reflect enough of a home’s heat to make a major difference in their heating bill – keeping it from soaring.
When combining this new technology with the new stipulations in BC’s new roofing laws and you’ll see major changes taking place on your roof. According to the new laws, professionals must create more efficient roofs. Green builders are actually welcoming this, especially regarding cool roofs. Contractors and builders want green certification today, so they’re also looking into ways of reducing a home’s overall heating costs. For these constituents, reflective or cool roofing materials are growing more mainstream, whether they consist of asphalt, metal, or composite.
If you or your customers are thinking about reroofing your home with a cool roof, you must first understand that these roofs typically cost more than traditional roofs. There are also some other factors you must consider.
Your Heating Bill
When the hot sun is beating down on your home, a reflective roof will help keep it cooler. However, the Cool Roof Rating Council (CRRC) says that these roofs don’t lower your heating bill and it may actually raise it slightly. This is why installing these roofs only makes sense when you have extremely hot, humid summers. This is also why you’ll see most of these roofs in southern and southwestern states. Here the amount of money saved throughout the summer outpaces the small increase in heating bills throughout colder months.
The Cool Roof Rating Council (CCRC) uses two measurements for rating cool roofs’ performance. These are:
- Solar reflectance: How much of the sun’s energy the roof reflects
- Thermal emittance: How well the roof releases any heat absorbed
These both use a scale of 0 – 1. Roofs measuring closer to 1 do better.
Energy Star Savings
According to the CCRC, cool roofs save homeowners 7 – 15% in cooling costs. Energy Star only recognizes cool roof products that cut a homeowners’ peak cooling demand 10 – 15%. This means that steep-slope products must reflect at least 0.25 of the sun’s energy if they want to receive the Energy Star rating. They must also show a 0.15 solar reflectance under normal conditions, three years later. While Energy Star doesn’t require third-party certification of this performance, it’s up to the CCRC to verify that products meet these levels.
Some professionals have found that more people show interest in cool roofing than actually buy them. This is because they’re cost prohibitive. For instance, Tamko, a top roofer in his area, charges $80 more for every 100 square foot of installed. Lamarite slate composite cool roof shingle than they do for their non-reflective products in the Northeast.
Scott Heitmeier, ABC Supply’s business manager for their steep-slope roofing, says the high price scares people off. He feels that addressing this must happen before these roofs will start to take a stronghold in the market.
Results Last Longer
There are some studies that show cool roofs do last longer than a traditional roof. This is because they don’t absorb heat. According to Daniel Roberts, a roofer from Surrey, darker shingles cook at higher temperatures. The founder and owner of Castle Roofing also add that they don’t do as well as lighter colored ones. So, anyone living in a hot area should choose shingles with lighter colors. These won’t only reflect heat and save you money, but it will also make the shingles last longer. Roberts admits this is the reason he was installing light-colored shingles on roofs throughout Surrey way before cool roofing was proven energy-efficient. For him, this is merely a buzzword – not something new.
Problems With Insulation
Roberts does admit that if you have a lot of insulation and radiant barriers, you don’t need a cool roof. In fact, using a cool roof over the top of 10 – 12 inches of insulation only results in negligible savings. This is something that Easley agrees with. He says reflecting 90% of the heat won’t necessarily result in large savings because there are codes in place that make you insulate your attic. However, he does believe that cool roofing makes sense if you have air conditioning ducts in a home’s attic, especially leaky ones.
Whether you want a cool roof or not, you should still consider watching this Youtube Video from the US Department of Energy: