Founder | BPI® Energy Auditor Certified Professional
Energy-saving roofs reflect sunlight and keep the building cool by absorbing less heat. Among the many energy-saving roofs, asphalt shingles are one efficient option to lessen the extra burden on home appliances during hot days.
Asphalt roofs can save energy by using a lighter physical color and if they use solar-reflective materials. However, it is hard to determine the amount of energy asphalt shingles will hold because of factors like material, color, shading, roof orientation, age, and others.
This article will discuss how asphalt roofing saves energy, how much energy it can save you, some tips for saving extra energy and maintenance, and other benefits of asphalt shingles. Moreover, we will talk about some alternative energy-saving roofs and tax credits on asphalt shingles.
Energy-Saving Roof Basics
It is natural for a house to get warm during summer and cool in winter. However, some factors contribute to the cooling and warming of the home apart from the atmospheric influence.
Energy-saving roofs target those factors that amplify the heating process during summer. Since the sun is the primary source of heat, the energy-saving roofs focus on balancing the absorption and reflection of sunlight.
Do Asphalt Roofs Save Energy?
Asphalt roofs save energy by reflecting more sunlight and absorbing less heat. This roof material can reduce the surface temperature by more than 50 °F (28 °C), resulting in lower HVAC energy expenditures.
This process is similar to our clothes choices during summers. On a hot sunny day, we like to wear light-colored clothes to absorb less heat from the atmosphere and reflect the sunlight so that our bodies remain cool.
The same applies to housetops. Roofs are like the attire of the house, and energy-saving roofs keep homes cooler by reflecting most of the sunlight than conventional roofs do.
Asphalt shingles are efficient at blocking UV rays. They are durable too. However, asphalt roofs are not among the most energy-saving roofing materials. Other options are more efficient at reflecting sunlight, including green roofs, metal roofs, tile roofs, terracotta, and slate roofs.
How a Roof Qualifies As Energy-Efficient
Roofs that qualify as energy-efficient are designated by Energy Star. A roof needs to meet certain criteria for gaining the Energy Star tag. There are two main categories of roofs—low-slope and steep-slope.
Here is a table for Energy Star roofing criteria based on government standards:
| S.No. | Roof Type | Initial Solar Reflectance | Solar Reflectance after 3 Years |
| 1. | Low-sloped roof | Equal or more than 0.65 | Equal or more than 0.50 |
| 2. | Steep-sloped roof | Equal or more than 0.25 | Equal or more than 0.15 |
The warranty on reflective roofs is the same as non-reflective roofs. Manufacturers need to offer the guarantee to gain the Energy Star certification.
Moreover, a reflective roof must simultaneously fulfill both initial and later (after three years) Solar Reflective Index (SRI) criteria. The top will not get an Energy Star rating without an initial, later solar index and warranty.
Asphalt Shingles Energy Star Ratings
Not all asphalt shingles are rated as Energy Star roofs. Only those shingles fulfilling the Energy Star criteria are designated as reflective roofing—the rest are simply ordinary asphalt shingles. Hence, it is necessary to look for the rating before purchasing.
For example, an IRC Topper asphalt shingle has 0.30 initial and 0.29 later solar reflectance, 0.88 initial and 0.87 later thermal emittances, and 31 initial and 29 later SRI. Thus, the IRC Topper Asphalt Shingle qualifies as an Energy Star roof.
How Much Energy Can an Asphalt Cool Roof Save You?
A cool (reflective) asphalt roof can save you up to 15% on your current electricity bills by cutting down the usage of air conditioners. However, energy savings is dependent on many factors. Thus, it is challenging to determine the exact amount of energy a cool roof can save you.
If the roof has an Energy Star rating, you need not be worried about anything else. Otherwise, the color of the shingles, solar reflectivity, and thermal emission are a few factors that need to be considered to save energy with roofs.
Cool roofs not only save you money on energy bills, but they also contribute to climate change mitigation and urban heat island reduction on a larger scale.
And it’s not just consumers that are afforded cost-saving benefits from energy-efficient roofing. It also saves the government money on electricity production costs. In light of this, you may be wondering if you can get any kickbacks from the government for saving it money?
Can You Get Tax Credits on Energy Saving Roofs?
Yes, you can get tax credits on energy-saving roofs. In the US, the government provides tax credits to those who apply Energy Star-certified metal and asphalt roofings in their homes. The tax credit amounts to 10% of the total cost, up to $500. However, tax credits do not include installation costs.
There are two main requirements to get tax credits on roofs apart from Energy Star certification—they must be “metal roofs with appropriate pigmented coatings” or “asphalt roofs with appropriate cooling granules.”
Tips To Save Extra Energy With Asphalt Shingles
As we have discussed earlier, not asphalt shingles are energy-efficient.
Therefore, it is best to check the Energy Star rating before purchasing rooftops. Energy Star-approved roofs are made to reflect more sunlight and are composed of materials that absorb and emit less heat later on.
Next we will consider some variables that contribute to energy-saving and how we can save extra energy by manipulating these components.
Solar Reflectance
Solar reflectance (or albedo) is the topmost factor in energy-saving or consumption.
The more the sunlight is reflected, the less the burden on the air conditioner. So, to make the roof more energy-efficient, we need to increase the solar reflectance of the roof surface.
Albedo relies significantly on the material type, color, and surface texture. For example, smooth and shiny surfaces reflect more light than rough and matte surfaces. Moreover, lighter colors also reflect more.
Tip: When choosing shingles, make sure to purchase smooth, shiny, and light-colored shingles. Besides the fact that your roof has an Energy Star rating, these additional factors will save you energy in the long run.
Thermal Emittance
Thermal emission is directly proportional to solar reflectance. However, some materials heat up slowly and emit heat gradually, whereas some materials heat up quickly and cool down in a few hours.
So, thermal emittance is tricky to manage as it can have an impact in two ways.
In the first, the roof will heat up during the daytime and emit heat gradually during the night. In the second, the top will heat up in the initial hours of sunlight, but it will cool down quickly in the evening, making the house cooler at night.
Tip: If you prioritize cool nights after spending the day in the office, choose the second option, whereas, if you stay at home during the day, the first option is best. You need to check out the thermal emission of the roofing material in the product details.
Color and Reflective Coating
The color and reflective coating are relevant in the same manner as solar reflectance. However, if your roofing is intact and you’re not planning to spend a massive budget on changing it to cool roofing, a cheaper option can be coloring and reflective coatings.
The reflective coating of light color materials increases the reflectivity of the surface.
Opt For Granular Asphalt Shingles
This tip pertains particularly to asphalt roofing. There are two types of asphalt shingles—granular and non-granular. Granulated asphalt shingles are more efficient at blocking UV rays.
For this reason, granular asphalt shingles with an Energy Star rating are best to choose.
Timely Maintenance
Shingles lose their efficiency over time. The table presented above shows how solar reflectivity decreases after years of usage. However, timely maintenance against weathering activities can lengthen their lifespan.
Moreover, there is potential for algae to develop over the roofs in the rainy season, making them darker and less reflective. Therefore, cleaning once or twice a year is best to enhance the efficiency of cool roofs.
Asphalt Shingles Maintenance Tips
Asphalt shingles are the most famous roofing option among US homes for two reasons—cost and durability. Asphalt shingles are cost-effective as they cost much less than other roofings. Moreover, they are durable too.
However, asphalt shingles can only serve their best if appropriately maintained. You can maintain your asphalt roof with three techniques:
- A cleaning schedule
- Repair or replace damages shingles
- Keep a record
Cleaning Schedule
It would be helpful to follow a cleaning schedule twice a year. Roofs are best to clean during spring and fall. In spring, cleaning the roof prepares it for harsh sunlight and rain during summer.
During the rainy season, algae, plants, and trees can grow over the roofs and in open seams of walls. So, it is best to remove all these things just after the monsoon ends. That is, in the Fall.
Keeping a cleaning schedule helps you save money in the long run. It also increases the reflectivity of shingles, making them more energy-efficient.
Repair or Replacement
Along with scheduled cleaning, a homeowner should repair the damaged portion or replace shingles damaged beyond repair. It is a necessary step to keep the house safe from seasonal activities.
If you do not fix the damaged patches promptly, it may cost you a lot of money down the road.
Keep a Record
It is best to record cleaning, repairing, and replacements. You can also keep a record of annual expenditure on maintenance. The documentation will help you lengthen the shingles’ lifespan and manage the maintenance costs.
Some Alternatives to Asphalt Shingles
Asphalt shingles are an excellent energy-efficient roofing system for a budget. Most US homes use asphalt roofing as their primary choice. However, other options are equal or more efficient than asphalt shingles.
Here are four alternatives of asphalt shingles that can save you energy:
- Metal roof
- Tile roof
- Green roof
- Terracotta roof
- Roof coatings
Metal Roofs
Metal roofs are best at reflecting solar radiation. Therefore, they are one of the top options for energy-efficient roofs. Metal roofs with Energy Star certification and appropriate pigmented coatings are also eligible for tax credits under federal policies.
Tile Roofs
Tile roofing is another good option in the roofing system. Tiles are highly reflective and less absorbent. Moreover, they also give an aesthetic value to the house.
There are so many options available in the market. So, make sure that the roof you buy has an Energy Star rating.
Green Roofs
Green roofs are living roofs with plants and vegetation on the terrace. The soil creates an insulation layer between the rooftop and sunlight. As a result, most light is absorbed by the plants, and significantly less heat is absorbed into the building.
Thus, green roofs keep a house or building energy-efficient. However, it might be a little challenging to maintain a green roof during all seasons.
Terracotta Roofs
Terracotta roofs are one of the oldest forms of roofing. They are efficient at energy saving. Baked or burned terracotta slates are good insulators. However, terracotta tiles might not be as reflective as metal and tile roofing.
Roof Coatings
If your non-reflective roof is still new and you see no sign of deterioration, roof coatings might be the best option to turn your roof into an energy-efficient one.
Roof coatings are paints that are good at reflecting solar radiation. This option is the cheapest among all energy-efficient options. However, coatings work best on flat surfaces.
There’s no need to worry about completely replacing your roof if it is still in good condition, so a roof coating might be the best option in this instance.
Conclusion
Asphalt shingles are among the most famous energy-efficient and cost-effective roofings. Approximately 75% of US homes have asphalt shingles.
Asphalt shingles save energy by reflecting sunlight, absorbing less heat, and blocking UV rays. Additionally, they save energy by cutting down HVAC costs.
Light-colored asphalt shingles have cooling granules and an Energy Star rating that will save you up to 15% on your electricity bill and provide you with 10% federal tax credits up to $500.
Sources
- Energy.gov: Cool Roofs
- Energy Star: Roof Products Key Product Criteria
- Berkley Lab: Definitions and Terms
- Coolroofs.org: CRRC Rated Products Directory User Guide
- EESI: Fact Sheet | Cool Roofs
- Energy Star: Federal Tax Credits: Roofs
- ScienceDirect: Solar Reflectance
- Corrosionpedia.com: Thermal Emittance
- OSTI: Weathering of Roofing Materials-An Overview