If a spa holds 900 gallons of water at 65°F, how many BTU's are needed to heat it to 105°F?

To determine how many BTU's are required to heat the water in the spa from 65°F to 105°F, it's important to know the formula for calculating the heat energy needed. The basic formula is:

[ \text{BTU} = \text{Weight of Water (in lbs)} \times \text{Temperature Change (°F)} \times \text{Specific Heat of Water (1 BTU/lb°F)} ]

Given that 1 gallon of water weighs approximately 8.34 pounds, the weight of the water in the spa can be calculated as:

[ 900 \text{ gallons} \times 8.34 \text{ lbs/gallon} = 7,506 \text{ lbs} ]

Next, calculate the temperature change needed:

[ 105°F - 65°F = 40°F ]

Now, substitute this information into the formula:

[ \text{BTU} = 7,506 \text{ lbs} \times 40°F \times 1 \text{ BTU/lb°F} = 300,240 \text{ BTU's} ]

It seems there might be a rounding when it refers to the total required BTUs, as