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Finding The Correct Size Heat Pump

Published by Makayla Ruth on 11/11/2021

Finding The Correct Size Heat Pump

In the market for a heat pump pool heater? You’ve come to the right place. A heat pump is an excellent choice to heat your swimming pool. Some qualities of a heat pump include:

  • Less Energy Used Over Long Periods of Time
  • Low Operating Costs
  • Most of the Energy is Converted to Heat
  • Will Often Outlast Gas Heaters
  • Fewer Repairs
  • Environmentally Friendly

First things first, we must figure out the number of BTUs (British Thermal Units) required to heat your pool, then we will be able to find the correct sized heat pump. Below is a simple equation that will help you find the answer of how many BTUs are needed for your swimming pool.

Heat Pump Size Equation:

  1. Determine your desired water temperature in °F.
  2. Determine the average air temperature of the coldest month during which you plan to use your swimming pool in °F.
  3. Subtract the average air temperature from your desired water temperature to calculate the required temperature rise.
  4. Calculate the surface area of your swimming pool (Pool Length x Pool Width)
  5. Calculate the required BTU output per hour: multiply, surface area x temperature rise x 12

Let’s Do An Example Together

  • For sake of conversation, let’s say you live in the northeast and your desired pool temperature is 82 degrees Fahrenheit.
  • In the northeast the average ambient air temperature during the month of September is 61 degrees Fahrenheit.
  • By subtracting the average air temperature from the desired water temperature you get 21 degrees Fahrenheit.
  • Next, let’s say your pool is 16’ x 32’, the surface area (Pool Width x Pool Length) would be 512 square feet.
  • Lastly, calculate the required BTU output per hour (surface area x temperature rise x 12) (512 x 21 x 12) which would come out to 129,024 required BTU.

Once you have come to an answer, it is always smart to go up a size with all heaters. This way, less energy is wasted and more energy is saved. For example, if you get a heat pump with the required (but minimum) BTUs it will have to run longer to heat the entire surface area of your pool. However; if you get a larger sized heat pump, it will not have to run for long periods of time to heat the surface area of your pool. Going with a larger model will end up saving you time, money and energy.

Since we know it is always better to go up a size, to not only save energy but also money; the best recommended heat pump would be the 140k Raypak Heat Pump.

E-Z Test Pools is here to assist you with any questions you may have when it comes to purchasing the right sized heat pump for your pool. Contact us at or visit any of our stores today!