Given a winter design temperature of 25°F and an indoor temperature of 75°F, what is the heat loss due to infiltration at 25 cfm?

To calculate the heat loss due to infiltration, you can use the formula that estimates the heat loss based on the difference between the indoor and outdoor temperatures, the rate of air infiltration (in cubic feet per minute), and the specific heat capacity of air.

In this case, the indoor temperature is 75°F and the outdoor winter design temperature is 25°F. The temperature difference is 75°F - 25°F = 50°F.

The formula to calculate heat loss due to infiltration is:

[ \text{Heat Loss (Btu/h)} = \text{CFM} \times \text{Temperature Difference (°F)} \times 1.08 ]

Where:

• CFM is the rate of air infiltration (in cubic feet per minute),

• The temperature difference is calculated as explained above,

• 1.08 is a constant which accounts for the density and specific heat of air.

Plugging in the values:

[ \text{Heat Loss} = 25 , \text{cfm} \times 50 , \text{°F} \times 1.08 ]

Calculating gives:

[ \text{Heat Loss} = 25 \times 50 \times 1.