Lesson 6: Thermal Mass

Thermal mass is a term in building sciences that indicates how well temperature is regulated inside. The lower a building’s thermal mass is, the better the building’s ability to quickly adjust temperatures. This may be a positive or a negative.

Doing the science

1. Start the Sunny Shelter Simulation by clicking on the "Sim" tab.
2. Make the following selections:
   • House Size: Small
   • Sheltering: Earth Sheltered
   • Window Direction/Tint/Season: North Facing/Tinted/Summer, South Facing/Not Tinted/Winter
   • Window Size: Small
   • Thermal Mass: Low
   • Material R-value: 10
3. Click on the Design House Now button.
4. The Energy Usage Thermometer is to the right of the image. Record the value in Table 1 below.
5. Click the Design Menu button to return to the main screen.
6. Repeat steps 2-5 but first change window tint to absent. Then repeat the choices again but change season from summer to winter until you have measured all four values. (Note: be sure that when in summer, you have the window direction set to north and the window tinted and when in winter, you have the window facing south and no tint.)