An energy-efficient home offers plenty of benefits. For example, you are likely to experience low and high temperatures, save money on utility bills, and have a higher resale value than comparable non-energy-efficient homes.
One way to make your home energy-efficient is to invest in an energy-efficient roof. Coincidentally, what makes for an energy-efficient roof is also what makes for a quality roof.
Apart from the artistry and materials, there are several other factors to consider, such as the roof’s color, insulation, and ventilation.
This article will examine which color roof is the most energy-efficient.
What Color Roof is the Most Energy-Efficient?
Shingle colors can majorly impact a roof’s energy efficiency. If your top priority in a roof is energy efficiency, choose a light color such as white or light grey to get the maximum benefit. Lighter colors conserve energy better because they reflect heat, solar radiation, and light rather than absorb them.
This feature makes your home easier to cool during summers and helps you save money.
Most roofing materials and shingles are available in various colors, with lighter versions prevailing over darker versions on energy efficiency each time.
For instance, a study revealed that a white roof was 4.62% cooler on a hot day in Arizona than a non-white roof. Furthermore, during the hottest part of the day inside the building (5 pm), a white roof was 8.49% cooler than a non-white roof.
Lastly, during the maximum internal temperature increase, from 7 am to 5 pm, the white roof stayed 6.97% cooler than the non-white.
White Vs. Black
Black-colored roofs usually get 10 to 15 degrees warmer than the white-colored roof on sunny days. However, during the evening, black-colored roofs heat faster as compared to white-colored ones. Both white and black-colored roofs show similar nighttime temperature profiles.
Light-colored roof shingles absorb less heat during summers. Consequently, your air conditioner works better, consumes less energy, and reduces energy bills.
On the other hand, a dark-colored roof will probably heat your home’s rooms best, particularly those on the highest floor. As a result, your cooling system must work harder to compensate for the extra heat, increasing your energy bills.
The reverse holds in winter. A dark roof brings in more heat from the sun than a light-colored roof. Thus, dark colors are beneficial at absorbing heat which is quite helpful if you live in a cold winter climate and your main goal is to keep heat inside during the colder months.
If your primary goal is to keep heat out, a dark-colored roof will work against you. A dark-colored roof can reach temperatures much higher than the outdoor air temperature—sometimes as high as 90 degrees. This development isn’t just bad for your home but also detrimental to the environment.
Other Factors Impacting the Energy-Efficiency of Your Roof
As many as 90% of roofs in the US are poorly designed and built with dark, heat-absorbing, non-reflective materials.
While the color of your roof plays a role in your home’s overall efficiency, it shouldn’t be the only thing you pay attention to when buying roofing material. Here are some other factors that can impact your roof’s energy efficiency:
1. Solar Reflectance Index
The Solar Reflectance Index (SRI) measures the roof’s ability to reflect solar heat and release absorbed heat (thermal emissivity). The larger the SRI, the better.
According to research conducted by the Lawrence Berkeley National Laboratory, increasing the SRI from 25 to 40 can reduce the temperature of your roof by over 13 degrees. This reduction can lead to 15-20% savings on your electricity bill.
Remember, the key to an energy-efficient roof is its ability to reflect the sun’s heat away from your home. This process results in less heat transfer to your attic, a cooler attic, and less heat transferred to your house.
Solar reflectance may not seem very important in colder regions. However, even if you live in a city that experiences short summers, you can benefit from substantial savings.
2. Heat Retention
Since hot air rises and roofs are exposed to a lot of solar energy from the sun, the air in your roof cavity is generally a lot warmer than the air in other parts of your house. That’s why managing the area under your roof is imperative in terms of your house’s heating efficiency.
Roofing materials can differ in terms of their natural insulation properties. Those with a high ‘thermal mass’ are slow to release and absorb thermal energy, which helps maintain a comfortable and constant temperature inside your house.
Energy-efficient roofing materials, such as slate, ceramic, stone, or concrete tiles, will absorb and retain heat and emit warmth inside your ceiling cavity.
On the other hand, metal roofing is an excellent conductor of heat but a poor insulator. Thus, metal roofs can be perfect for homes situated in hot climates.
Another factor that increases your roof’s energy efficiency is ventilation. Good ventilation prevents the buildup of heat in your attic.
If there’s no proper ventilation, the heat will move inside your home. Plus, if temperatures get too extreme, it won’t just increase your energy bill but can damage your roof.
You can install wind-powered, electric, or static vents in your attic to allow proper ventilation. Nevertheless, a roofing expert can give you a clearer idea of the type of vent you should choose and the ventilation you need.
A general rule of thumb is to aim for a 1:300 ratio (1 square foot of ventilation for every 300 square feet of roof surface).
Upgrading your insulation is another way to improve your roof’s energy efficiency. The material minimizes heat flow between various areas in your home, such as a duct, wall, or attic.
Good insulation prevents warm air from leaking out of your home during winter and retains cool air during the summer.
As heat rises and mostly escapes through the roof, installing roof insulation such as ceiling batts can help minimize this process.
Investing in insulation won’t just help your roof become more energy-efficient; it will create a more comfortable living environment and save you significant amounts of money in cooling and heating costs.
What Roofing Material Is the Most Energy-Efficient?
There are many roofing materials to choose from, and some are better at lowering electricity bills than others. Moreover, some might be more costly to install but might lead to higher savings in the long run. For instance, a metal roof is more expensive upfront. However, it might be the best choice for your monthly electricity bills.
Here is an overview of the most popular roofing materials and how energy-efficient they are:
1. Metal Roofs
Metal is one of the best roofing materials. It makes for a highly energy-efficient roof for residential purposes, can last over 50 years, and requires minimal maintenance.
Metal roofs tend to have a high reflectivity rating and dissipate heat naturally. According to researchers from the US Department of Energy, metal roofs panels or shingles can reduce your cooling costs by almost 25%.
When it comes to color, light-colored metal is generally a more energy-efficient roof option than dark-colored metal roofs.
2. Composite Roofs
Composite roofing is made with recycled material and designed to appear very similar to slate roofing. This material is available in energy-efficient categories.
If you are planning to opt for composite roofing, choose a light color to get the highest level of energy-efficient roof.
3. Asphalt Roof
Almost 75% of the houses in the US have asphalt roof shingles installed in their homes. However, while this commonly-used roofing material is affordable and durable, its energy efficiency levels differ dramatically between products.
Nevertheless, these days, manufacturers are developing new asphalt roof shingles with solar-reflecting granules that increase the SRI and extend the roof’s lifespan by keeping the surface temperature low.
Owens Corning’s Cool Roofing Collection is a great example. It offers shingles with a reflectance value higher than 20. They also come in darker colors, usually associated with low SRI values.
4. Tile Roofs
Tile is also one of the most energy-efficient roofing materials available on the market. Tile roofs allow air to flow under the tiles, which adds to their ability to release any absorbed heat.
You can have tile roofs pretreated to maximize heat reflectivity. However, if you already have a tile roof installed, you can treat it with reflective coatings.
Tile roofs are most commonly used in warm and sunny climates, such as Arizona, where they mesh with the earthen appearance of homes. They are typically made with ceramic and clay.
However, they can be made with cement as well. Clay has higher reflective properties than cement.
Nevertheless, the reflectance of the tile roof primarily depends on its color. For example, red clay can only reflect 20% of solar energy, whereas white clay tiles can reflect up to 70% sunlight.
Regardless of which roofing material you choose, make sure to check if it’s Energy Star-rated to allow for maximum energy savings. A professional and well-reputed roofing company can help you decide which energy-efficient roof material is most suitable for your home, situation, and region.
Do Roof Coatings and Paints Improve Energy Efficiency?
Whichever roofing material you pick, it is always good to add a reflective coating to the material to attain higher reflectiveness.
Some roof coatings use specialized reflective pigments that reflect sunlight. On the other hand, certain roofing materials offer increased solar heat reflectivity, helping with energy savings during summers.
One type of coating is known as Elastomeric coating. It is a thick waterproof coating and offers heat and UV ray-resistance.
This coating decreases your monthly energy bill and reduces your roof’s overall wear and tear, requiring you to replace it less frequently.
Elastomeric coating will have a higher solar reflectance rating than a black or dark roof and can prevent up to 75% of solar heat from entering your house. Elastomeric roof coating cost $0.15-$0.75 per square foot.
Keep in mind that roof coating or paint is not suitable for every roof. You shouldn’t coat or paint your roof if:
- Your house has an asphalt roof.
- Your roof already has a cool coating (like most metal roofs).
- You don’t notice any peeling or chipping.
- Applying coating or pain will negatively impact your roof’s warranty or render it void altogether.
What Are the Benefits of Energy-Efficient Roofs?
Energy-efficient roofs can make a significant difference in your home. Here are some of the benefits these roofs offer:
1. Energy Savings
The less heat enters your house through the roof, the less you will spend on cooling costs during summers. If you invest in an energy-efficient roof, you can save approximately 7 to 15% on your monthly energy bill.
2. Extended Lifespan of Your Roof
Excessive heat can seriously damage your roof. This is particularly true for asphalt roofs that degrade quickly upon exposure to the sun.
An energy-efficient roof that reflects heat and harmful sun rays will last longer. As a result, you won’t have to worry about re-shingling or replacing it as often as a conventional roof.
3. Increased Resale Value
Energy-efficient roofing is an excellent selling point. If you sell your house in the future, you can perhaps get a higher price for it when you choose to sell it.
A light-colored roof can decrease the temperature of your roof and reduce your cooling bills. However, the color of the roof isn’t the only thing that you should pay attention to when buying roofing material.
Instead, you should look at the solar reflectance index, heat retention capability, insulation, and ventilation properties as well.
Lastly, when investing in an energy-efficient roof, ensure it is Energy Star-rated. This way, you can get the maximum value for your buck!