Can the paint on the outside of a house help keep the house cool in hot weather? Yes. Some types of paint have ingredients (materials used to make something) that reflect (to bounce back from the surface of an object) up to 80 percent of sunlight. These paints also radiate (to send heat, light, or energy out in all directions) heat back into the air. These types of paints can reduce the amount of air conditioning needed to cool a house by up to 30 percent.
These paints work well in hot, dry climates. What happens in a place where it is hot and humid? When it’s humid, there is a lot of water vapor (water in a gaseous state) in the air. The water vapor prevents heat that has been absorbed by the paint from going back out into the atmosphere. These paints do not work as well in places with high humidity, such as Singapore, which is near the equator.
Scientists in Singapore wondered how to solve this problem. They turned to the natural process of evaporative cooling. Evaporative cooling is how the human body keeps cool. When it is hot, people sweat. Sweat is mostly water. Sweat evaporates (the process by which water changes from a liquid to gas) from the surface of skin. As the liquid water in sweat changes to water vapor, heat loss occurs. This process helps keep your body at the right temperature.
The scientists used cement and nanoparticles (very small particles that cannot be seen without a microscope) to make a paint that holds water. The water then slowly evaporates into the atmosphere, cooling a house as heat loss occurs. The new paint also reflects about 90 percent of sunlight. By holding water and allowing it to evaporate, the paint radiates 95 percent of heat it absorbs back into the atmosphere. Overall, houses in Singapore painted with the new paint decreased their use of electricity for air conditioning by up to 40 percent!
What Do You Think? How could painting every house with cooling paint impact the environment?
Photo Credit: (t)Hill Street Studios/Blend Images LLC/Getty Images, (b)MEzairi/Shutterstock
