When it comes to absorbing heat from sunlight, not all colors are created equal. Some colors absorb heat more readily while other colors tend to reflect it away. This is an important consideration when choosing colors for building materials, clothing, cars and more. Understanding which colors absorb the most and least amount of heat can help make informed decisions to stay cooler in hot environments.
How Color Affects Heat Absorption
The amount of heat a color absorbs from sunlight depends on its light reflecting properties. Objects appear a certain color because they reflect that colored light back to our eyes while absorbing other wavelengths. For example:
- A red object absorbs all sunlight wavelengths except red, which it reflects.
- A blue object absorbs all wavelengths except blue, which it reflects.
- A white object reflects all wavelengths of visible light equally.
When an object absorbs sunlight energy, it converts that energy into heat. So colors that reflect more of the sun’s light absorb less of the sun’s heat.
Colors That Absorb the Most Heat
Darker colors absorb more heat than lighter ones because they absorb more light energy. Of all visible colors, black absorbs the most heat from sunlight. A black car left in the sun can reach temperatures of 150-200°F inside. Darker paint colors like black, brown, and dark blue absorb a lot of heat as well. Here are some examples of colors that absorb high amounts of heat:
- Black – absorbs up to 95% of sunlight
- Dark brown – absorbs up to 90% of sunlight
- Dark blue – absorbs up to 80% of sunlight
- Dark green – absorbs up to 75% of sunlight
- Red – absorbs up to 72% of sunlight
Lighter shades of these colors absorb slightly less heat than their darker counterparts because they have higher reflectivity. For example, light blue absorbs about 10% less heat than dark blue because it reflects more light. But even pale and medium versions of colors like blue, green, and red absorb heat at high rates of 60-75%.
Colors That Absorb the Least Heat
On the opposite end of the light absorbing spectrum, lighter colors reflect the most sunlight and absorb the least amount of heat. White is the most reflective color, absorbing only 5-25% of sunlight. Other light colors also absorb much less solar heat:
- White – absorbs 5-25% of sunlight
- Yellow – absorbs 25-50% of sunlight
- Light blue – absorbs 25-40% of sunlight
- Light green – absorbs 25-40% of sunlight
- Light gray – absorbs 30-50% of sunlight
Medium to lighter shades of colors like yellow, light blue, light green and light gray are your best choices for deflecting solar heat. For example, pale yellow only absorbs 25-30% of sunlight, compared to 60-65% absorbed by darker yellow hues.
How Color Impact Heat Absorption in Different Materials
While color is the main factor affecting heat gain across materials, the actual composition of the material makes a difference too. Here’s a look at how color impacts heat absorption with some common materials:
Paint
Paint color has a major impact on heat absorption. Dark paint colors can make painted surfaces up to 50-60 ̊F hotter than light colors. Here is the heat gain for some painted colors in direct sunlight:
| Paint Color | Temperature Gain ( ̊F) |
|---|---|
| White | 10-25 ̊ |
| Yellow | 25-30 ̊ |
| Red | 30-35 ̊ |
| Blue | 30-40 ̊ |
| Green | 35-45 ̊ |
| Black | 50-60 ̊ |
Clothing Fabrics
Clothing color also plays a role in heat absorption. Darker fabrics absorb more heat than light ones, warming your body in cool weather but heating it up more in hot conditions. Here are some examples of heat gain for clothing colors:
| Clothing Color | Temperature Gain ( ̊F) |
|---|---|
| White | 5-10 ̊ |
| Tan | 10-15 ̊ |
| Red | 15-20 ̊ |
| Black | 20-30 ̊ |
The fabric itself makes a difference too. Dark cotton absorbs more heat than lighter cotton. Synthetic fabrics like polyester tend to absorb less heat than natural fabrics, even in darker colors.
Building Materials
Color is very influential on the heat absorption of building materials. Here are the amounts of heat gain for some common housing materials and colors:
| Material & Color | Temperature Gain ( ̊F) |
|---|---|
| White paint | 10-25 ̊ |
| Unpainted wood (light) | 20-35 ̊ |
| Unpainted wood (dark) | 30-45 ̊ |
| Red brick | 30-45 ̊ |
| Black asphalt shingles | 50-70 ̊ |
| White roof shingles | 10-25 ̊ |
Color makes a big difference in roofing materials in particular. Black asphalt shingles easily reach up to 175°F in summertime sun. White roofs only warm to about 100°F and can reduce cooling costs by 10-20%.
Strategic Use of High and Low Heat Absorbing Colors
Knowing which colors absorb more or less heat allows us to strategically use them to our advantage. Here are some ways to utilize high and low heat absorbing colors:
- Paint houses light colors to reduce heat gain inside.
- Wear light colored clothing to stay cooler in hot climates.
- Use darker colors on floors to absorb warmth in colder climates.
- Choose bright white roofing materials to reflect heat.
- Select darker vehicle paint to absorb warmth rapidly in winter.
- Plant trees with lighter leaves near buildings to shade and reflect heat away.
Choosing the right colors for environmental conditions can make a big impact on warmth and cooling needs. Just keep in mind darker colors absorb more heat, while lighter ones absorb less and can help maintain cooler temperatures.
Conclusion
When exposed to sunlight, darker colors with low reflectivity absorb the most heat. Black absorbs up to 95% of solar energy, followed by other darker shades like brown, blue, red and green. On the flip side, lighter colors with high reflectivity absorb the least amount of heat. White reflects up to 95% of sunlight, while other pale colors like yellow, light blue and light gray absorb much less heat than their darker counterparts.
Strategically using darker colors to absorb heat in colder climates and lighter high reflectivity colors to stay cool in warmer conditions can help regulate temperatures. Understanding the heat absorption properties of different colors can lead to informed choices in paint, clothing, building materials and more.
