Use residential heat pump for pool heating?


Jun 21, 2024
Use residential heat pump for pool heating? | Blog - Microwell

A heat pump, as a source of heat, whether for a family house, a company building or a swimming pool, is the cheapest and most available heating all year round in a suitable climate. Heat pumps are strongly supported and often subsidized in many countries and their number is continuously increasing. The European Heat Pump Association (EHPA) estimates the number of heat pumps currently in operation in Europe at 20 million. With around 3 million added in 2022 alone. This is in line with the REPowerEU 2030 strategy. The European Union is targeting 60 million heat pumps installed by 2030, which would mean an annual growth rate of almost 15%. Whether the strategy will be fulfilled or partially fulfilled, we do not know at this point, but we often come across the question of whether a residential heat pump is suitable for heating pool water.

Our recommendation is clear and that is to use residential heat pump (a so-called "domestic heat pump") for a house (building, company, hotel...) and use a pool heat pump for a swimming pool. And not to combine the systems.

A domestic heat pump or heat pump "for space heating" is a heat pump that is primarily intended for heating buildings (houses, companies, hotels, etc.) in the form of most commonly underfloor heating. On the other hand, a pool heat pump is a special type of heat pump designed exclusively for heating the water of swimming pools, hot tubs, and water attractions. Both of these heat pumps work on the same principle and often look very much alike, but on the inside they are different in many ways.

Both heat pumps work to exchange heat from air to water for heating and from water to air for cooling. To do this, they use the elementary behavioral characteristics of gases; when pressed you heat them up, on the contrary, whenreleased (evaporated), you cool them down.

However, the biggest difference lies in the material of the water exchanger. Since the heat pump for underfloor heating of the house works with just an ordinary water, which is at best treated with inhibitors, it usually uses stainless steel exchangers. This water is not particularly corrosive or aggressive, and therefore stainless steel (or copper) is long-lasting and reliable.

However, a pool heat pump must usually works with high-corrosive water, which is often treated with chlorine or salt. The lifespan of a stainless steel heat exchanger in this case would not be more than a few weeks, a few months at most. The pool heat pump is equipped exclusively with a titanium heat exchanger. Our ones from Microwell use the purest titanium (99.2% titanium) called "Grade 1".

Differences between home and pool heat pumps can also be found in other areas, but this is beyond the scope of this article. Below in the table you can see a basic overview of the differences.


Table: a basic overview of the differences between a home and a pool heat pump.

If you have already invested in a domestic heat pump and would like to release its unused capacity into the pool in the summer, you have several options. The most ideal is definitely to let your home pump rest and get a separate pool heat pump.

If still you would like to utilize it, you need to take some measures in order to to do. Since pool water is often highly corrosive, it is out of the question to connect it directly to a domestic heat pump. Damage to the heat exchanger is exempt from the warranty conditions and the repair of the device would be very expensive. There are options to connect the circuit of the home heat pump to the pool through an additional heat exchanger. However, this solution is very little used in practice due to the various technical pitfalls it opens. With additional heat loss and overall reduced efficiency, two completely different caloric units are combined. I mean different energy outputs at a given moment.

Pool heat pumps operate at significantly higher water flows and a lower temperature difference than domestic heat pumps. The difference in flow can be up to 4 times higher with a pool heat pump and the difference in water temperature up to 5 times lower with a pool type compared to a house pump. This results in a problematic setup of the system as such. We can compare it to a top cyclist on a modern bicycle who will try to go at maximum speed in the lightest (lowest) gear.

Building such a system is not impossible, but challenging. A big disadvantage, in addition to additional heat losses and reduced efficiency that another heat exchanger represents, is the fact that you need your residentialheat pump from September to April in most location cases of Northern hemoshere. So if you have an indoor pool, your pump simply won't have enough capacity to heat both the house and the pool during heating season

The issue of using a residential heat pump to heat pool water is, of course, technically more comprehensive than this article. However, our goal was to convey our unequivocal position and that is not to combine these systems, on the contrary, to purchase a high-quality separate pool heat pump that meets the latest energy requirements and that will provide you with the required comfortable water temperature for pleasant moments in the pool.

Ing. Peter Hrubina

Division manager


Mobil: +421 911 413 990


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