When it comes to your roof, the color of your shingles can have a significant impact on the temperature inside your home. Darker colored shingles absorb more heat from sunlight, which can lead to higher cooling costs during hot summer months. Lighter colored shingles reflect more sunlight, helping keep attics and interiors cooler. So if you’re looking for ways to beat the heat, installing lighter colored roof shingles is an effective option.
How Roof Color Affects Temperature
The main way roof color affects interior temperature is through a process called heat transfer. There are three types of heat transfer that impact a home’s interior temperature:
- Conduction – Heat transfers from warmer objects to cooler objects through direct contact. For example, heat from your warm roof transfers into the cooler attic air through conduction.
- Convection – As air is heated it rises, pulling cooler air in to take its place. This circulation of air currents transfers heat. Attic ventilation works via convection.
- Radiation – Heat can transfer via electromagnetic waves, which allows heat to radiate from a warm object to a cooler object without direct contact. For example, sun warming up the roof surface.
A roof’s ability to absorb or reflect sunlight greatly impacts heat transfer into the home. Darker colored shingles absorb more solar radiation, heating up the roof surface more. This warmer roof surface then conducts and radiates more heat into the attic. The increased attic heat creates more convection as hot air rises and exits through vents, pulling more hot air from inside the home. This process keeps the attic dramatically hotter, creating an oven-like effect.
Color and Temperature Comparison
Studies have quantified the temperature difference between lighter and darker roofs. One Stanford study found that on a 90°F day, the surface of a black roof reached 170°F, while a white roof only reached 110°F. Another study found that a black roof was 50-90°F hotter than reflective white roofs under summer sun. An analysis by the Heat Island Group calculated that white roofs are 33-39°F cooler than dark roofs on summer afternoons.
The table below compares surface temperatures of different colored shingles under summer sunlight:
| Roof Color | Surface Temperature on 90°F Day |
|---|---|
| Black | 170°F |
| Dark Gray | 155°F |
| Red | 145°F |
| Light Gray | 125°F |
| White | 110°F |
As the data shows, white shingles can be 50-60°F cooler than black shingles in the summer sun. That’s a dramatic difference in thermal performance.
Impact on Cooling Costs
The hotter attic and interior temperatures created by dark roofs significantly increase air conditioning usage and electricity bills. A 2000 Florida study found that switching from a black roof to a reflective white roof reduced average summer cooling energy use by 20%. Another study found white roofs saved around 20% on cooling costs in warm southern climates. Research on California homes found non-reflective black roofs required 25% more cooling energy than reflective white surfaces.
A cooler attic and interior from lighter colored shingles can make a major impact on keeping your home comfortable without excessive cooling costs. The table below shows estimated cooling savings from switching to white shingles:
| Location | Estimated Cooling Savings from White Roof |
|---|---|
| Southern California | 20% |
| Southwestern U.S. | 20-25% |
| Southeastern U.S. | 10-20% |
| Midwest | 5-10% |
| Northeast | 2-5% |
Homeowners in hot southern climates like California, Texas, and Florida could save hundreds of dollars per year by switching from dark shingles to reflective white shingles.
Reflectivity Metrics
When comparing roofing materials, an important metric to look at is solar reflectance, also known as albedo. This measures how much sunlight is reflected away versus absorbed as heat. A higher reflectance percentage means more reflected light and less heat gain. Reflectance can be measured on a scale of 0 to 1, or as a percentage.
Some common reflectance values:
- White roof coatings – 0.70 to 0.90 reflectance
- New white shingles – 0.25 to 0.70 reflectance
- Aged white shingles – 0.50 to 0.70 reflectance
- Gray shingles – 0.30 to 0.50 reflectance
- Black shingles – 0.05 to 0.20 reflectance
Another useful metric is Solar Reflectance Index (SRI). This incorporates both reflectance and material emittance (ability to radiate absorbed heat). Standard black shingles have an SRI around 10, while white shingles are 60-80. Higher SRI values reduce roof heat gain.
Cool roof building codes are starting to mandate minimum reflectance or SRI values for roofs. For example, California’s Title 24 requires low-sloped roofs to have 0.63 minimum reflectance or 75 SRI. Steep-sloped roofs need 0.20 minimum reflectance or 16 SRI. White shingles will meet or exceed these cool roof requirements.
Popular Light Color Options
If you want to reap the cooling benefits, what lighter shingle colors should you consider? Here are some of the most popular light roofing color options:
- Bright White – A crisp, clean white appearance. Reflectance of 0.65-0.70 is common. Provides maximum heat reflection.
- Antique White – A warm off-white, sometimes with a cream or ivory tint. Reflectance around 0.60.
- Cool White – A very light gray shade that maintains good solar reflectance (0.50-0.60). More subtle than a pure white.
- Driftwood – Light beige or tan color. Reflectance of 0.45-0.55. Coordinates with natural color schemes.
- Silver Gray – Light but not white gray color. Still provides decent solar reflectance (0.40-0.50).
Even though darker than bright white, these lighter shingle colors still greatly reduce heat gain compared to darker options. They provide cooling benefits while coordinating with certain home styles and color schemes.
Other Ways Lighter Colors Reduce Heat
Installing reflective roof shingles is one of the most effective ways to reduce solar heat gain and lower interior temperatures. But light colors also have benefits beyond reflectance:
- Daytime Appearance – Dark roofs look uncomfortably hot on sunny days. Light colors remain cool and pleasing.
- Night Sky Cooling – Light colors emit more heat at night, helping continue cooling when the sun sets.
- Lower Urban Heat – White roofs reduce the urban heat island effect in cities and neighborhoods.
- Improved Comfort – Light colors keep attic spaces cooler, reducing hot air intake into the home.
- Consistent Temperature – Reflective roofs have smaller temperature fluctuations between day and night.
So even beyond just reflectance, lighter colored shingles can provide aesthetic and comfort benefits as well.
Specialty Reflective Options
If maximum reflectance and energy efficiency are your priorities, specialty reflective roofing materials can take benefits even further. Some options to consider include:
- Cool Metal Roofs – Made from reflective metals like aluminum, coated steel, or copper. Offer reflectance of 0.50-0.70+.
- White Coatings – White elastomeric acrylic coatings for existing roofs. Achieve very high 0.70+ reflectance.
- Cool Tiles – Clay or concrete roofing tiles formulated with reflective coatings or special glazes.
- Advanced Membranes – White thermoplastic or PVC membranes offer energy efficiency for low-slope roofs.
If your main priority is energy efficiency and maximum reflectance, these specialty products can offer enhanced cooling benefits compared to standard roof materials.
Consider Maintenance with Light Colors
One downside of very light shingles is that dirt and discoloration over time will lower the reflectance. Proper roof cleaning and maintenance helps counteract this. Also look for reflective coats that maintain appearance and reflectance longer.
Some other potential drawbacks of lighter colored roofs:
- Can show dirt easier
- Higher glare potential
- Heavy water marks if not well-drained
- Not suited for all home styles
Make sure to weight the benefits versus any potential maintenance concerns for your particular home.
Conclusion
Installing light colored roof shingles is an effective strategy to reduce solar heat gain and lower cooling costs. White and cooler tone shingles greatly reduce the roof’s surface temperature compared to dark options. This keeps the attic and interior spaces more comfortable without excessive air conditioner usage.
Homeowners report cooling energy savings of 20% or more after switching to reflective white shingles, especially in hot southern climates. Specialty reflective roofing materials can provide even greater efficiency. Just be aware of potential maintenance needs with lighter colors.
By choosing lighter roofing colors, you can beat the summer heat and save on energy bills. Your shingles’ color has a real impact on interior comfort and cooling requirements. So if you want to stay cooler naturally, turn to lighter roofing colors to reduce heat gain.