Hot Tub Heating

Bowman heat exchangers for hot tubs. A new solution that enables hot tubs to be heated faster and more economically.


Every hot tub installation is different in some way, so the answer can depend a number of issues;

  1. the capacity of the hot tub?
  2. the outside air temperature?
  3. the heating system type?
Hot tub

In many installations, where the hot tub is being heated via an electric heater, the answer is ‘a very long time’ – in some instances it can be up to 24 hours from cold! This is because a typical 3kW electric heater raises water temperature by around 1-2⁰C per hour.

Understandably, many owners find this is far too long, as it restricts the amount of time the hot tub is available for use. A further issue is the amount of energy required. With the average cost of electricity being more than double the cost of gas per kWh*, it’s no surprise that many hot tub users experience a sharp increase in energy costs with some electrically heated hot tubs adding an extra £500.00 – or even more - to the annual electricity bill!

However, by switching to a more efficient energy source, such as gas or biomass boiler heating, used in conjunction with a Bowman heat exchanger, it is possible to dramatically reduce hot tub heat up times AND reduce energy costs.



As the hot tub, spa and swim spa markets have grown significantly over the past few years, so has the demand for more efficient heating solutions.

Using knowledge gained over many years at the forefront of swimming pool heating, Bowman can now offer a range of hot tub heat exchangers, which enable hot tub users to switch away from the inefficient electric heaters that are usually supplied with the unit.

How does it work?

This new approach to heating hot tubs is based around two separate water circuits - an efficient gas or biomass boiler provides hot water to the heating circuit and the Bowman heat exchanger transfers heat to the pool water circuit. The Bowman heat exchanger ensures the water in these two circuits is always kept separate, avoiding corrosion of the boiler internals and contamination of the hot tub water, shown in the simplified schematic illustration below.

Hot Tub schematic

The benefits include significantly faster heat up times – usually in around 2 - 3 hours, as water temperature is raised by up to 12⁰C per hour - and vastly reduced energy costs compared to electric heating. In ‘real world’ operation, customers have reduced their heating costs by £500.00 per year.

Bowman offer a comprehensive range of heat exchangers that are suitable for hot tubs as they are easy to install and provide long life durability.These include the super compact 25 kW EC80-5113-3T, which at just 368mm long is so compact it can be installed virtually anywhere.

For further information on hot tub heating using Bowman heat exchangers, download the marketing bulletin ‘Heating Hot Tubs Faster’, our case study leaflet ’Energy Efficient Hot Tub Heating for Luxury Golf Resort’, or speak directly to our technical sales team on +44 (0) 121 359 5401

*Energy Saving Trust – energy calculations – March 2016