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What Size Heat Pump Do I Need for My Swimming Pool?

What Size Heat Pump Do I Need It’s confusing to size a heat pump for your swimming pool as a new pool owner, isn’t it? But trust us, you just have to consider a few factors during making the decision.

In this article, we are going to answer your question, ‘what size heat pump do I need for my swimming pool?’

You will surely enjoy the pleasure of swimming after installing the correct sized heat pump.

So, let’s go now!

The things to consider beforehand

As we said before, there are a few things you have to consider. If you get the correct-sized heat pump once in a while, you’ll get the cost-effective performance from your above-ground pool heater.

Size of your swimming pool

The very first thing to be considered is your pool’s size. The heat pump’s size directly depends on how much water the heat pump will heat.

In a simple word, you have to know how powerful a heat pump is to be. So, we can say, the bigger your pool in volume, the stronger your heat pump should be.

The climate of your place

The climate of where you live is another important factor to be considered. If you live in a comparably warm area, your pump doesn’t need to work too hard. In this case, if you have an average-sized pool, you simply need a small to standard-sized heat pump.

On the other hand, if you are in a colder area, your pump needs to work hard for your pool. Most heat pumps out there will serve you around the 50-degree mark.

Also, there are heat pumps that are designed to work at a lower temperature (30 degrees). So, these kinds of heat pumps can help you in colder climates.

How often you swim

Well, your swimming habit doesn’t affect the main calculation needed to size a heat pump.

But if you swim in the pool every single day, then heating speed is a factor to consider. The stronger the pool heat pump is, the stronger the heating ability is. So, you need a strong heat pump if you use it the most.

Now, let’s dive into the main course.

Calculation of sizing a heat pump

Believe it or not, you’re half done with the sizing stuff. Now, for ensuring accuracy, you just have to use some mathematical formula. Follow these steps:

  1. Target a maximum temperature you want to heat your water up to. For example, you want to determine 80 degrees as the hottest temperature.
  2. Note the average temperature of the coldest time of the year(where you live). Suppose, you live in Florida, Hence, the average temperature of the swimming season is 60 degrees.
  3. Now, do the quick math, subtract the average temperature from the target temperature.

From above, Target temperature-the average temperature
= (80-60) degrees
= 20 degrees

So, the temperature increase number is 20 degrees.

  1. Measure the size of your pool(surface area)
    The formula is,                                                           Suppose the values are,
    Length= 30ft
    Width= 15ft

Length x Width= Surface area
= (30 x 15)ft= 450sqft

  1. Measure how much heating power(BTUs) is needed to heat your power. You actually have all the values. Now, put them on the formula;

Temperature increases x Pool surface area x 12= BTUs
=20 x 450 x 12= 108,000 BTUs

You are done! If you calculate like this example, if a heat pump size is 108,000BTUs or more, it’s a good fit.

Now, know something else for having a better idea about your heat pump.

About pool heater efficiency

Your swimming pool heat pump’s energy efficiency is measured by COP (coefficient in performance). The higher the COP number is, the more efficient it is.

But, there’s no standard test to measure this COP stuff. But there’s a typical way, manufacturers measure this testing by a heat pump with an outdoor temperature of 80 degrees F as well as pool temperature of 80 degrees F.

The general range of COP is 3 to 7 and it converts to an efficiency of 300%-700%. What does it mean?

It means, for every unit of electricity it usually takes to run the compressor, you will get approximately 3-7 units of the heat out of your heat pump.

The choice of location

Your heat pump demands a very large amount of air to function properly, so, the choice of location is very important to be considered.

In this case, a wide and suitable place has to be found. Remember, the indoor operation doesn’t work here properly.

Equipment of the heat pump

Basically, the high-quality heat pumps out there are equipped with corrosion-protected heat exchangers! Thus, they can heat any swimming pool water.

Whether it may be cared for with bromine, free chlorine & total chlorine, ozone or chlorine-free products. In addition, the use of pools with seawater can also be possible.

If you’re eager to know about the differences between free chlorine and total chlorine, there are ways!

About water temperature

It’s a must to have the minimum difference between the current and desired water temperatures. If it’s greater, you have to run the heat pump for a longer time.

The chemical balance of your water is also needed for all the season, all the time. Try not to neglect them.

The level of pH, chlorine, etc should always be on point. Sometimes, the water faces chemical imbalances and higher pH is one of them. You can learn how to lower the pH in pool water.

Use of a solar blanket

You will be glad to know that solar blankets reduce the required heating time as well as the spa heating costs.

Evaporation is a reason for 75% of the pool’s heat loss and the evaporation is minimized with a solar blanket. It actually plays the role of a barrier between the air and your pool.


Now, you are totally ready to install a heat pump for your pool. Isn’t it 100% clear to you what size heat pump do I need for my swimming pool? In the end, it should be yes!

We have tried to show you every single point which is a must to consider. We broke them down so that you can easily get it all.

Now, we hope that you’ll purchase a correct-sized heat pump for your pool. Happy sizing!

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