Swimming Pool Heat Exchanger Size Guide

Swimming pools require various chemicals, machinery and equipment to maintain and remain operational. One of those vital components is a pool heat exchanger, which can heat pools by utilising water from a boiler, heated water circuit or solar panel. This affordable device is easily maintainable and a great way to keep your pool resting at the desired temperature. In this guide, we outline how to size a swimming pool heat exchanger and provide some valuable tips.

How Does a Swimming Pool Heat Exchanger Work?

A heat exchanger is a simple bit of equipment with no moving parts to go wrong, and if selected correctly, it can be extremely efficient.

Two separate mediums will run either over the tubes or through the tubes of the heat exchanger with no opportunity for cross-contamination.

The internal tubestack has a number of baffles precisely placed to encourage optimum turbulence, which in turn improves the efficiency of the heat transfer process and exchanges heat from one medium to the other.

With so many brands, sizes and options to choose from, it can be challenging to know what pool heat exchanger is suitable for you. Luckily, Bowman has covered all bases to ensure that every swimming pool can be equipped with a heat exchanger designed for them. 

The Bowman heat exchangers have mastered this process by continually developing their durability, control and installation time.

The Benefits of a Pool Heat Exchanger

This process is fast and comes with various benefits, including:

  • Saving excess energy 
  • Easy to install 
  • Easy to disassemble
  • Durable materials with up to a 10-year guarantee
  • Premium quality 
  • Bowman has been in heat transfer for over 100 years

Now, let us take a look at how to size a swimming pool heat exchanger by examining its key features and specific measurements. 

How to Size a Swimming Pool Heat Exchanger

This step is incredibly vital to ensure that your whole swimming pool is heated. There are a couple of components to consider before making a decision. These include: 

  • Pool Size
  • Available Energy (KW) (how is it heated?)
  • Primary heat source temperature 
  • Water flow rate of each circuit if known 

So, let's go into a bit more detail on how to size a pool heat exchanger correctly.

Pool Size

The swimming pool’s water capacity plays a big part in sizing your heat exchanger as it indicates how much energy is required to heat the whole pool. 

For example, if you purchased a 40m³ that is designed to cover 8,800 gallons and owned a pool at 20,000 gallons, that unit would fail to cover the majority of your swimming pool. That is why it's important to size your pool before purchasing a heat exchanger. 


If you’re using a lower temperature on your primary side (usually from a heat pump or solar heated application) it is likely that you will require a longer heat exchanger which has a larger surface area. 

Bowman have a range of heat exchangers specifically for these heat sources and can operate with primary temperatures as low as 40°c.

Primary Heat Source Temperature 

Bowman heat exchangers are installed in applications ranging from hot tubs to Olympic sized swimming pools. All these applications can be used alongside a boiler for the primary heat source.

When sourcing a heat exchanger, it’s important that you have a boiler with sufficient energy. It’s often a misconception that heat exchangers generate more power; they only transfer heat that is already available.  

Water Flow Rate

The water flow rate is crucial to ensure that the thermal energy is transferred correctly to the pool. If the water flow cannot reach the right temperature, the available energy will fail to circulate through the heat exchanger.

Additionally, a common misconception with water flow is that people believe there needs to be a noticeable difference in temperature between the pool water entering and when it returns. However, if you increase the water flow rate, the pool will heat up quicker.

If you require further assistance on sizing a pool heat exchanger, then get in touch with our expert team.

Swimming Pool Heat Exchanger Sizing Chart

This chart displays the Bowman heat exchangers we offer at 1st Direct Pools.

Part Number

Pool Size (m³)

Boiler Flow (l/min)

Max Pool Flow (l/min)

Heat Transfer at 82 °C (kW

Heat Transfer at 60 °C (kW)

Dim. A (mm)

Dim. B (mm)

Dim. C (mm)

Weight (kg)









































What is the Best Heat Exchanger for My Swimming Pool?

With a large selection of Bowman heat exchangers available in different materials, including titanium, cupro nickel and stainless steel, you can find the right one for you with us at 1st Direct. 

When selecting a unit to be installed in a salt chlorinated pool we would recommend that you use either cupro nickel or titanium heat exchanger/tubestacks. All materials are suitable for the marine industry which is a large part of Bowman’s business, so we are confident they will have no problems with a salt chlorinated pool.

We recommend that professionals install these heat exchangers to ensure they're fitted correctly and without complications.

We hope you have found this guide helpful! You can get in touch for more information about heat exchangers or our other products like our range of pool heaters, for instance.