How do you choose a swimming pool size?

Size does matter when choosing a pool heater. Especially a gas pool heater. To help you choose the proper size, there are a few simple steps to do.

First: Determine what temperature you would like to keep your pool during the coldest months of operation.

Second: Look at the average temperature during the coldest months in your area you when you would be using your pool.

Third: Subtract the average temperature of the coldest month from the temperature you would desire. This will give you the temperature rise that your pool will need to reach your desired temperature.

*This is only the first few steps. For a gas heater to be efficient, you need to properly size your heater. To determine the proper size heater simply follow these additional steps.*

First: Determine your pool's area square footage. To do this multiply the length times the width

( L x W = area).

Second: Multiply the pool area x the temperature rise x 12.

This formula will give you the btu/hour output requirement.

OR

The capacity of most pool heaters are rated in BTU's or British Thermal Units. One BTU is the amount of heat required to raise the temperature of one pound of water, one degree F. And since there are 8.33 gallons of water per pound, it takes 8.33 BTU's to raise one gallon of water, one degree F.

Now let's calculate:

1. Determine the number of gallons in your pool (G).

2. Determine the amount in temperature that you want to raise the pool temp (the easiest way to figure this is to use the air temp as the minimum and the desired pool temp as the maximum) (Delta T).

3. Calculate the number of BTU's needed (BTU) per gallon of water by multiplying step 2 x 8.33. Multiply this number times the gallons of water in your pool (G). This is the number of BTU's to raise your pool temp from the minimum to desired temp.

4. Determine how FAST you want to be able to go from the minimum temp to the desired temp (in hours) (H).

5. Divide the total number of BTU's from step 3 by the hours in step 4 to yield the BTU'S per hour that your heater will need to deliver.

6. Multiply Step 5 by a error factor of 20% and add to step 5. This is approximately the size of heater that you will need.

Example:

1. Assume pool volume, G = 10,000 gallons 2. Assume 80F desired pool temp and 60F air temp. Delta T = 80 - 60 = 20F 3. BTU's per gallon x Delta T: 8.33 x 20 = 166.6 BTU's per gallon. BTU/Gal x Gallons (G): 166.6 x 10,000 gal = 1,666,000 Total BTU's. (Wow, seems like a lot!) 4. Assume I want to be able to warm the pool in two days of continuous operation = 48 hours. 5. Total BTUs / Hours: 1,666,000 / 48 = 34,708 BTU's per hour. 6. (BTU/Hr x 20%) + BTU/Hr: 34,708 x 0.20 = 6,941 BTU's 6,941 + 34,708 = 41,649 BTU's per hour.