Enter the surface area of the duct, the heat transfer coefficient, and the temperature difference into the calculator to determine the duct heat loss.

Duct Heat Loss Calculator

Enter any 4 values to calculate the missing variable

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Duct Heat Loss Formula

The following formula is used to calculate the duct heat loss for a given surface area, heat transfer coefficient, and temperature difference.

Q = A * U * ΔT

Variables:

  • Q is the duct heat loss (W)
  • A is the surface area of the duct (m²)
  • U is the heat transfer coefficient (W/m²K)
  • ΔT is the temperature difference between the inside and outside of the duct (°C)

To calculate the duct heat loss, multiply the surface area of the duct by the heat transfer coefficient and the temperature difference between the inside and outside of the duct.

What is Duct Heat Loss?

Duct heat loss refers to the loss of heat from the air as it travels through the ductwork in a heating, ventilation, and air conditioning (HVAC) system. This loss occurs due to the temperature difference between the air inside the duct and the surrounding environment. The heat is transferred through the duct walls to the outside environment, leading to a decrease in the temperature of the air being delivered to the conditioned space. Proper insulation and sealing of ductwork can help minimize duct heat loss and improve the efficiency of the HVAC system.

How to Calculate Duct Heat Loss?

The following steps outline how to calculate the duct heat loss.

  1. First, determine the surface area of the duct (A).
  2. Next, determine the heat transfer coefficient (U).
  3. Next, determine the temperature difference between the inside and outside of the duct (ΔT).
  4. Finally, calculate the duct heat loss using the formula Q = A * U * ΔT.
  5. After inserting the values 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.

Surface Area of Duct (A) = 10 m²

Heat Transfer Coefficient (U) = 5 W/m²K

Temperature Inside Duct (Tinside) = 30°C

Temperature Outside Duct (Toutside) = 20°C