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.

Comments are closed.