How many BTUs are lost per hour if a 1,000 sq ft roof has an R-value of 19 and the temperature difference is 20°F?

To find the heat loss in BTUs per hour through a roof, you can apply the formula that connects the area, the temperature difference, and the R-value. The formula for calculating the heat loss is:

[ \text{BTUs per hour} = \frac{\text{Area (sq ft)} \times \text{Temperature Difference (°F)}}{R\text{-value}} ]

In this case, the area of the roof is 1,000 sq ft, the temperature difference is 20°F, and the R-value is 19. Plugging these values into the formula gives:

[ \text{BTUs per hour} = \frac{1,000 \times 20}{19} ]

Calculating that, we perform the multiplication first:

1,000 sq ft * 20°F = 20,000

Next, we divide by the R-value:

20,000 / 19 ≈ 1,052.63 BTUs/hour

Rounding this value gives approximately 1,053 BTUs per hour. This calculation demonstrates how the thermal resistance of the roof (indicated by the R-value) impacts heat loss. A higher R-value means less heat is lost, while a