Enter the outside temperature and the solar gain factor into the calculator to estimate the attic temperature. The solar gain factor represents the increase in temperature due to the effect of solar radiation.

Attic Temperature Formula

The following formula is used to estimate the attic temperature:

AT = OT * (1 + SG)


  • AT is the attic temperature (°F)
  • OT is the outside temperature (°F)
  • SG is the solar gain factor (dimensionless, ranging from 0 to 1)

To estimate the attic temperature, multiply the outside temperature by the sum of 1 and the solar gain factor.

What is Attic Temperature?

Attic temperature is the temperature within the attic space of a building. It is influenced by the outside temperature and the amount of solar radiation the attic receives, which can significantly increase the temperature inside the attic. Understanding attic temperature is important for proper insulation and ventilation to prevent heat-related issues and improve energy efficiency.

How to Calculate Attic Temperature?

The following steps outline how to estimate the Attic Temperature.

  1. First, determine the outside temperature (OT) in degrees Fahrenheit.
  2. Next, determine the solar gain factor (SG), which is a value between 0 and 1 that represents the increase in temperature due to solar radiation.
  3. Use the formula from above: AT = OT * (1 + SG).
  4. Finally, calculate the Attic Temperature (AT) in degrees Fahrenheit.
  5. After inserting the variables and calculating the result, check your answer with the calculator above.

Example Problem:

Use the following variables as an example problem to test your knowledge.

Outside temperature (OT) = 85°F

Solar gain factor (SG) = 0.7