How to Determine the Right Size Heater for Your Pool

For many pool owners in North Carolina, a pool heater is an absolute necessity. Not only does a heated pool ensure you’ll have a pleasant experience each time you dive in, but a pool heater can also significantly extend your swimming season.

Choosing the right size heater for your pool will help you strike the perfect balance between comfort, convenience, and efficiency. You’ll want a heater that can warm your pool up quickly and easily maintain the desired temperature. However, if you choose one that’s too big, you’ll find that you’re wasting energy, which can get expensive.

Calculating the exact size pool heater you need can be a bit complicated, however, the following simplified estimates are a good starting point.

Simplified Calculation: BTU Estimate

The first step in determining your minimum heater size is to consider the size of your pool. Start by calculating the surface area of your pool by multiplying the pool’s length by its width. For example, if your pool is 15 feet by 30 feet, then its surface area is:

15 x 30 = 450 square feet

Next, divide the surface area by 3 and multiply the result by 1,000 to determine the minimum BTU size. Continuing with the example above:

450 / 3 = 150
150 x 1000 = 150,000 BTUs

It’s important to remember that this is a bare minimum. In most cases, it’s a good idea to go at least one size up, as this will speed up the pool’s heating process and help make up for heat loss that occurs due to evaporation, precipitation, and windy conditions. A larger pool heater is also recommended for pool owners who enjoy swimming at night of in the colder months.

As a general rule, recommended gas pool heater sizes are as follows:

Pool Size	Recommended Heater
16 x 32 feet	250,000 BTU
18 x 36 feet	325,000 BTU
20 x 40 feet	400,000 BTU

Variables to Consider

In addition to the volume of water you’re heating, other factors to consider include:

• Whether you’re heating a pool alone or a pool with a spa/hot tub
• The average temperatures where you live
• Your ideal water temperature
• How quickly you want your pool to heat up

If you like to keep your pool quite warm and there will be times when you need to heat it quickly, then choosing a larger pool heater is a better option. However, you may also be able to improve your heater’s efficiency by using a pool cover, which offers an additional layer of insulation. This helps hold heat in the water, reducing the work the pool heater needs to do and allowing it to better maintain your pool’s temperature.

Using a solar blanket in tandem with your pool heater will help you achieve warmer temperatures in shorter amounts of time. In some cases, you may find that it’s better to invest in a solar blanket rather than purchase a larger heater.

Consult with Our Pool Installation Experts

If you’re still not quite sure what size pool heater you need, don’t worry! The experts at Swim Inc. are here to help. Our pool installation experts will take care of all the details, including recommending the ideal heater size for your needs. Contact us today to schedule a consultation or call us now 919-629-1331.