Largest Range of Swimming Pool Heaters

As the leading pool heater suppliers, HeatPumps4Pools specialise in offering the widest range of swimming pool heat pumps from manufacturers that we consider to offer the best quality, reliability, price and performance. We have the largest range on the Internet at the lowest prices backed by our excellent customer service standards.We are the sole distributor to the UK and Europe for the excellent Heat Siphon range.We provide a knowledgeable, friendly service to assist you with the purchase and installation of your pool heat pump – so talk to the experts, please feel free to ask – any query at all. We are open 7-days a week. Continue reading

Pool Heat Pump Queries and Support

We are happy to answer any questions that you may have about using a heat pump on your pool or koi pond

Feel free to ask us any question about heating your pool or pond  using a heat pump

Koi Pond Heat Pumps

Heating Koi Ponds with Heat Pumps

At HeatPumps4Pools, we have a range of heat pumps specifically selected to be used to heat koi ponds.


Heat pumps can be successfully used to heat koi ponds through the winter and summer months.Using a heat pump as a pond heater will significantly reduce your pond heating costs.For use with koi ponds, it is important to select a heat pump that can operate down to low temperatures in order to maintain the required temperature of the pond throughout the winter.Typically a koi pond will be kept at between 10c and 15c throughout the winter.
The range of heat pumps that we recommend for koi ponds are the excellent Duratech Dura+ range. The Dura+ range come in different sizes of 7kw, 10kw, 14kw, 19kw, 22kw and 30kw of output heat. Beware of heat pumps that will only work down to about +7c, as these will become inefficient in very cold weather.

The Dura+ range can operate down to -15c and have a “hot-gas” defrosting mechanism which will quickly clear away any ice that may form on the heat pump at low temperatures.

Dura plus heat pump on koi<br />


Heating a koi pond with a heat pump will always be significantly cheaper than using gas, oil or direct electric heating.

A heat pump will return between 2.8 and 6.7 times its input energy as heat depending on the air temperature.

This factor of efficiency is called the COP (Coefficient of Performance) and you can view a graph of how the unit performance varies with air temperature on the Dura+ product page Here

At an air temperature of 0c, the Dura+ has a COP of about 4.

The Dura+7 has an input power of 1.2kw and therefore with an air temperature of 0c, it will still output 4 x 1.2 = 4.8kw of heat for only 1.2kw of input power.

The COP rises to over 6 meaning that the heat pump can produce 6 x 1.2 = 7.2kw of heat from only 1.2kw of input power.

These heat pumps therefore have an efficiency of between 280% and 670%. A typical gas boiler will only be around 85% efficient and direct electric heating is about 95% efficient.

This high efficiency makes heat pumps the cheapest form of heating, even at low air temperatures.


Running Costs

As an example of running costs, the Dura+ 7kw heat pump has an input power of 1.2kw (5.2 amps).

If your electricity costs say 9p per kwh then the running costs of the heat pump would be 9 x 1.2 = 10.8p per hour while the heat pump is operating

Except in extremely cold spells, and if sized correctly, the heat pump should not need to run 24hrs a day.

The heat pump will heat the pond to the required temperature and will then switch off.

The running time of the unit will depend on the air temperature and how well the pond is insulated or covered.

Assuming the heat pump needs to run for say 7hrs per day, the running cost for a Dura+ 7 unit would be 7 x 10.8p = 75.6p per day


The use of the Duratech Dura+ range of heat pumps on koi ponds does not invalidate the warranty in any way.

The only provision in the warranty document states that for koi ponds, the PH must be kept between 7.0 and 8.5 which is fairly typical for most koi ponds.

The concentration of medicinal chemicals that may be used in koi ponds is not sufficient to cause any damage to the unit.

The Dura+ units have a titanium heat exchanger which is highly resistant to corrosion from all chemical types including chlorine in swimming pools.

A copy of the warranty document is listed at the bottom of the Dura+ product listing, or can be viewed Here

Further Advice for Installing Heat Pumps on Koi Ponds

  • A backup heat source (eg electric heater) should be installed alongside the heat pump. This can provide additional heat in extremely cold weather conditions (eg below -5c) and also acts as a backup in the unlikely event that the heat pump fails.
  • In order to prevent damage to the heat pump, you must avoid water freezing inside the unit as this can crack the heat exchanger. The easiest way to avoid this is to keep the water circulation pump running when the air temperature falls below 0c.
  • A frost stat can be installed on the circulation pump to turn it on when the air temp falls below 0c.
  • The heat pump contains a pressure switch which detects when the circulation pump is running and water is flowing through the unit. In order for the pressure switch to work properly, it is advisable to install the heat pump on a pressurised water pipe as opposed to a gravity fed one. If the heat pump must be installed on a gravity fed water pipe, then we sell a separate water flow switch which can be used to detect water flow. Please Contact Us for details.
  • A separate heating element is now available which will melt any ice which builds up in the bottom of the heat pump. Please Click Here for details
  • Please also refer to the Installation Tips on our web site

Drip Tray Heating Kit

In extremely cold weather, the condendsation that drips from the heat pump evaporator coil can freeze in the bottom of the heat pump causing an ice build up.

We sell an optional kit that contains a special  heating wire controlled by a low temperature thermostat.

The heating element only turns on when the air temperature falls below zero and turns off again when the temperature rises.

The kit comes with all necessary parts and full installation instructions

Click Here to Purchase this Kit

Example Installations

Below are some photographs of a heat pond being heated through the winter using a Dura+ heat pump.


Another example below of a Dura+ heat pump heating a koi pond taken March2010



The pond owner reported that the heat pump has worked extremely well and maintained the pond temperature at 15c despite the snow !

The running costs were reduced by approx 60%

Another recent installation was on a 14,000 gallon pond in Norfolk and used a Dura+14kw unit to heat the pool.

The pool owner reported:-

I am writing to say I have been very impressed with the heat pump, I reckon over the past 3 weeks it has already saved me over £200 in heating oil”

The initial purchase cost of a heat pump may be higher than a traditional electric or gas pond heater, but you will soon recover the outlay through greatly reduced running costs.

Using a heat pump to heat your pond is also a more environmentally friendly method than using fossil fuels such as gas or oil and so you can also reduce CO2 emissions and do your bit for the environment !

You can see an excellent account of how another of our customers installed one of our heat pumps on their koi pond


What our customers say

Here are some quotes from our customers that are using Dura+ heat pumps on their koi ponds:-

Hi David,
AMAZING !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Took delivery yesterday morning, lucky for me my husband is on hols this week so it was plumbed in immediately, temp was at 15.5 degrees,went to work, returned at 2200hrs and it was up to 17.5 degrees, got up at 0600hrs – 19 degrees, by  early morning it reached the 20 degrees I had set it at, apparently it’s only kicked in once today to maintain the temp.
After seeing this unit working I now know that the old unit didn’t work as it should have from day one – all that time wasted – my poor fish – they’re now bombing around the pond at present (it’s going to cost me a fortune in food)
What an amazing piece of kit!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!.
Over the next week I will attempt to take some photo’s for you, for you to use if you want, also I am chairman of South Devon Koi Club, although we are having problems with our website at present (nobody knows how to load anything on it) will quite happily get a link put on for your company when we can find a man that can.
Next month I have a pond visit – 2 clubs visiting, if you have any info you wish for me to pass around, I would be quite happy to do so.

Many thanks for your help in resolving my problems.


Thank you so much for your help, I’m so impressed with the pump, keeping a steady 24 degrees – fish are loving it. It was a big outlay for me, but one of the best I have made, would recommend this pump to anyone who is thinking of heating their pondRegards

Any Questions?

If you have any questions regarding the use of heat pumps to heat koi ponds, please Contact Us and we will be delighted to answer them for you.

New Drip Tray Heater Kit

We have now produced a new drip tray heater kit for heat pumps that will be used over the winter months.

Drip tray heater kit for Duratech Dura plus heat pumps.

This kit contains an electric heater element that sits in the bottom of Duratech Dura+ heat pumps.

It can be required when the heat pumps are going to be operated at very cold temperatures – below 0c, for example on koi ponds, or for indoor pools.

Our genuine Duratech Dura+ heat pumps can continue to operate down to -15c, however the normal condensate water that drips from the evaporator coil can fall to the bottom of the heat pump and freeze causing an ice build up during long spells of very cold weather.

This kit includes all parts necessary to install the kit so that any ice that forms in the drip tray of the heat pump is melted into water.

The kit includes:-

  • heater element
  • temperature controlled switch
  • all necessary wires
  • installation instructions

The temperature controlled switch automatically turns the heating element on in very cold weather and turns it off again when the temperature rises to provide a fully automatic system.

The heating element is powered from within the heat pump and therefore does not require a separate power supply.

Please see the installation manual for more information.

To see details of this kit and pricing , please visit our web site at

How to Winterise Your Pool Heat Pump

How to Winterise Your Pool Heat Pump

Your pool heat pump is a valuable piece of equipment and so you should ensure that you protect it from damage that can be caused over winter.

If water is left in the heat pump over winter, then it can freeze to ice, expand and crack the heat exchanger in your heat pump.

This can be an expensive mistake and the cost of repairing the heat pump may be more than the unit is worth.

It is therefore worth taking a few basic steps to protect your heat pump during the winter.


Outdoor Pools

If you have an outdoor pool, then you will probably only use it during the winter months and your heat pump will be turned off during winter.

When your heat pump is installed, we recommend that a bypass kit is installed on the pipework.

The bypass kit allows your heat pump to be isolated from the water flow.











In winter, you should close the valves going in and out of the heat pump and open the bypass valve.

If you need a bypass kit, we sell them on our web site at

You can then loosen the connections to the front of the heat pump to allow all of the water to drain out of it.

Once the water has drained out of the heat pump, you should protect it by covering it with one of our top quality heat pump winter covers

Pool heat pump winter cover











Our winter covers are custom made to fit your model of heat pump.

They include special ventilation strips to allow any trapped moisture to escape and prevent corrosion of your heat pump.

You can see details of our winter covers on our web site at


Indoor Pools

Many indoor pools are used all year round.

In this case it is not possible to drain the water from the pool heat pump if the heat pump is still being used to heat the pool.

The heat pump must however still be protected from water freezing inside the unit during winter.

The best way to prevent freezing damage to the heat pump is to ensure that the pool pump is running whenever the air temperature falls below freezing (0c)

A frost stat should be fitted to the pool pump that automatically turns the pool pump on when the air temp falls below about +3c

Alternatively the pool pump can be set to run all of the time to keep the water moving and prevent it from freezing.

As long as the water is moving it will not freeze and will prevent damage to your heat pump.

If you do not use the heat pump during the winter, then drain the heat pump down and cover it as mentioned above for outdoor pools

Koi Ponds

Koi Pond Heat Pump from HeatPumps4Pools












Koi ponds are typically heated during the winter months.

Our Duratech Dura+ range of heat pumps are well suited to koi ponds as they operate down to -15c

As the heat pump will be used during the winter, it is not possible to drain the unit down.

A frost stat should be installed to ensure that the water pump is always running when the air temp falls below 0c

The procedure is the same as for indoor pools – see above


A pool heat pump is a valuable piece of equipment and when looked after will provide many years of service.

By draining down the heat pump, or by keeping the pool pump running, you can prevent damage from occuring to your unit over winter.

We hope that you found these tips useful.

Please let us know if you have any queries

Second Hand Heat Pumps

We can sell any second hand heat pumps that you may wish to dispose of.

We list second hand units in the section on our web site at

We only charge a fee if your unit sells.

We put you in touch with any interested buyers.

If we sell the unit for you, then you pay us a broker fee.

Please contact us if you have any pool heat pumps or equipment that you would like us to sell for you.