Can the Color of Your House Reduce Your Energy Footprint?
AbstractDid you know that the color of your house could save money? Do this experiment to see which colors regulate temperature best in different environments. Then convince your parents to paint the house and save some money on their energy bill. Maybe they will be so happy they will also increase your allowance!
Sara Agee, Ph.D., and Teisha Rowland, Ph.D., Science Buddies
This project idea was adapted from a science fair project by William S. in Mrs. Hannemann's 3rd grade class at Williams Elementary in Rockledge, Florida: S., William, 2003. "Does the color of your house affect the temperature inside of it?" Williams Elementary, Rockledge, Florida.
Investigate if the color of a structure affects the temperature inside the structure when in different environments.
How does the color of your house affect the temperature inside of it? To answer this, think about the clothes that you would wear on a hot, sunny day, when the outdoor temperature is really high. Would you rather wear a light-colored shirt, or a dark one? You would probably get much warmer in a dark shirt compared to a light-colored one. This is because the light-colored shirt reflects more light than the dark one does. The dark shirt, on the other hand. absorbs a lot of light. Light is a form of energy and the energy absorbed by the dark shirt warms up the shirt. The shirt then transfers the heat to your body, warming you up more than the light-colored shirt would.
This is also what happens if the sides or roof of a house is hot. As the surface temperature of the surface of the house increases, it increases the indoor temperature, warming up the rooms in the house. On hot, sunny days, people can use a lot of energy to keep their houses cool. If less energy could be used to do this, not only would it save people money on bills, but it may help the environment by decreasing the amount of energy we use! Is there a house color (like one of the many ones used for the houses in Figure 1, below) that would be best for people who live in a climate that is hot year-round? What about people who live in a climate that is cold year-round? Is there a color that would work well for people who have both very hot and very cold seasons?
Figure 1. These houses have been painted several different colors. How do the colors they are painted affect how warm the rooms inside get when it is very hot or cold outside? (Image credits: Reykjavic, Wikimedia Commons)
In this science project, you will investigate if the color of a structure affects the temperature inside of it. You will do this by painting shoe boxes with light, medium, or dark colors to model painted houses, and then putting the boxes in warm and cool environments. You will measure the temperature inside each box over time. Will color matter?
Terms and Concepts
- Outdoor temperature
- Reflection of light
- Absorption of light
- Heat transfer
- Surface temperature
- Indoor temperature
- How different are the surface, indoor, and outdoor temperatures of a structure?
- How do colors that reflect or absorb light affect the indoor temperature of a structure?
- Which colors do you think are best for saving energy in hot or cold climates?
- Morton, J. L (n.d.). Color & Energy Matters. Color Matters. Retrieved June 25, 2014.
- The Physics Classroom. (n.d.). Color and Vision. Retrieved July 23, 2012.
- TheInfoMine. (2010, August 28). Energy Efficient Paints For Your Home?. Retrieved July 23, 2012.
For help creating graphs, try this website:
- National Center for Education Statistics, (n.d.). Create a Graph. Retrieved June 25, 2020.
Materials and Equipment
- Shoe boxes (3)
- White, gray, and black paint. Latex or acrylic paint should work. Small samples of paint can usually be purchased at a hardware store and acrylic paints can be purchased at crafts stores.
- Paint brush
- Thermometers (4). Suitable thermometers are available from Carolina Biological, item # 745394.
- Heat lamp. A heat lamp is available from Carolina Biological, item # 701202. Alternatively, a heat lamp may be purchased at a local pet store or large animal supply store.
- Large tray
- Rock salt
- Plastic bag, preferably white
- Lab notebook
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- Collect 3 shoe boxes of the same size.
- Paint one box white, one box gray, and one box black. Allow the paint to dry completely.
- Make a data table in your lab notebook like Table 1 below. You will write down your observations in this data table.
|Box Color||Starting Temperature (°C)||Room Temperature (°C)||Heated Temperature (°C)||Cooled Temperature (°C)|
- Investigate how the temperature of the boxes changes at "Room Temperature."
- Put a thermometer in each box, place the boxes on a table, and place an external thermometer on the table.
- Record the "Starting Temperature" of each thermometer in your data table. Record the temperatures in degrees Celsius (°C).
- Put the lids on the boxes and leave them at room temperature for 30 minutes.
- Take each lid off and quickly record the "Room Temperature" in the data table.
- Investigate how the temperature of the boxes changes at a "Heated Temperature."
- Put the lids back on and place a heat lamp above the boxes to simulate a warm, sunny day.
- Arrange the boxes underneath the lamp so that they are all equally distant from the light source. This will be a control to be sure that one box is not getting more light or heat than another box because it is closer to the light source.
- Put the last external thermometer in the center of the boxes to measure the external temperature of the environment.
- Leave the boxes and the external thermometer under the heat lamp for 30 minutes.
- Warning: The lamp will become very hot! Be sure not to touch the lamp, or allow it to touch anything else!
- Take each lid off and quickly record the "Heated Temperature" in the data table.
- Were the temperatures the same or different? If the temperatures were different, which box heated up the most or the least?
- Put the lids back on and place a heat lamp above the boxes to simulate a warm, sunny day.
- Investigate how the temperature of the boxes changes at a "Cooled Temperature."
- Make a tray of ice by sprinkling a layer of ice with rock salt and covering it with a white plastic bag to keep the boxes dry.
- Put the lids back on and keep the heat lamp above the boxes this time put the boxes on top of the tray of ice to simulate a sunny winter day.
- Arrange the boxes underneath the lamp on the ice tray so that they are all equally distant from the light source. Put the thermometer in the center of the boxes.
- Leave the boxes and the external thermometer on the ice tray under the heat lamp for 30 minutes.
- Take each lid off and quickly record the "Cooled Temperature" in the data table.
- Were the temperatures the same or different? If the temperatures were different, which box stayed warmest? Which box cooled off the most?
- After you have recorded all the temperatures, make a bar graph of your data. You can make your graph by hand, or use a site like
Create a Graph to make your graph on the computer.
- On the graph, put the temperature on the left (the y-axis). Make a bar for each temperature measured for each colored box, and for the temperatures measured by the external thermometer.
- Compare the results using your graph. Which colors worked the best to reduce temperature changes in which conditions? Which colors would you recommend on the roofs of houses in climates that are hot year-round, cold year-round, or that have both hot and cold seasons?
Ask an Expert
- What about colors other than black, white, and gray? You can make this project more difficult by increasing the number of colors you choose. Most major paint manufacturers can tell you the Light Reflectance Value (LRV) of any color paint chip. White reflects 80% of the light and black reflects 5%. You can conduct your test for a series of colors with different LRV values. Will the temperature increase or decrease with the LRV number of the paint color? Which colors should you choose for hot or cold climates? What about climates with four full seasons?
- House color is only one aspect of house design. Does the material you choose on the outside of your house make a difference? In this experiment you used a painted shoe box, a paper product, to simulate a painted house. What about real materials used to cover houses? Try the experiment using different materials: adobe, stucco, wood, siding, metal, etc. Which materials are the coolest or the warmest? Use a light and dark colored version of each material. Do some materials have more extreme temperature differences than others? Which materials are the most stable against fluctuations? Which type of climate is suited best by each material?
- Another way to save energy is to use insulation, a material that is placed inside the walls of a structure to keep the indoor temperature from fluctuating. Compare different materials used for insulating walls: fiberglass, paper. Try a similar experiment by wrapping the shoe box with each material. Which materials provide the most stable indoor environment? Look up the R-factor for each material. Does it correlate with your results?
- In this science project you assumed that the roof would have full sun, but this is often not the conditions a real roof experiences. How do you think factors such as shade on a roof, water nearby, winds, and nearby roads may affect what is the most energy-efficient color for a roof? Design a project to test how one of these other factors may affect how the color of a structure's roof changes the temperature inside of the structure.
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