At a house on a particular day the outside temperature differs from the inside temperature by 65 degrees fahrenheit. The house has a 39 inch by 7 foot front door.[ with storm door] What would be the heat loss through the front door of the house on this day in btu?

This cannot be answered without much more information. What is the heat insulation coefficent for the door is the main thing missing.

This cannot be answered without much more information. What is the heat insulation coefficent for the door is the main thing missing.

why did 10 years pass and no one was able to answer?!

To calculate the heat loss through the front door, we need the heat insulation coefficient, also known as the U-factor, for the door. This coefficient represents the rate of heat transfer through a material or assembly. Without this information, an accurate calculation cannot be made.

However, I can provide a general explanation of how to calculate heat loss through a door using the U-factor if you have that information available.

1. Determine the U-factor: The U-factor is typically provided by the manufacturer and represents the rate of heat transfer through the door. It is measured in BTU/(hr·ft²·°F) or W/(m²·K).

2. Measure the area of the door: Multiply the width (39 inches) by the height (7 feet) to get the area of the door in square inches.

3. Convert the area: Convert the area of the door from square inches to square feet by dividing by 144 (since there are 144 square inches in a square foot).

4. Calculate the heat loss: Multiply the U-factor by the area of the door in square feet and the temperature difference (65 degrees Fahrenheit) to get the heat loss in BTU/hr.

Keep in mind that this is a general method, and the accuracy of the calculation depends on the specific U-factor value for the door in question.