Temperature losses through the walls and roof will be estimated based on the dimensions provided. For a more complex building shape, such as a tank or silo, you can switch to Advanced mode and enter the surface area manually.
Enter the surface area for the TOTAL combined wall area, the floor surface area, and the ceiling surface area. Select the appropriate insulation R-Factor values for each. Enter the known air volume of the space, and the number of air changes per hour required.