How much do Heat Pumps affect the Electricity Power Network?

December 14 2014

Regarding the specific info required by power providers for the heat pump for your home, we are surprised that a very efficient household appliance such as a Ground or Air Source Heat Pump gets so much attention when there are other appliances in the house which use a similar amount of energy and have higher start up current requirements but do not get the same level of scrutiny? If someone puts in a new tumble dryer to their house do they have to let the power provider know? We often hear from our clients that putting in heat pump requires a bigger transformer. 95% the heat pump systems we have installed in the past have been in houses with a standard 18kva supply and there have never been any issues as the modern heat pumps are so efficient and draw very little power on start up. A ground source heat pump with an incoming brine temperature coming in from the ground between and 4oC and 8oC and an outgoing heating temperature of 25oC – 30oC to the Underfloor Heating System will have a COP of approximately 6.5. You may think this is high as normally the COP associated with a Ground Source Heat Pump System is about 4.5 (Typically about 3.8 – 4.0 for Air Source Heat Pumps). However these figures that you see on a Heat Pump Data Sheet are based on an incoming brine temperature coming in from the ground at 0oC and an outgoing heating temperature of 35oC to the Underfloor Heating System. See image below of one of our recent installations where we were achieving a COP of 6.5 based on these sort of temperatures.

I have attached a table showing typical electrical consumption of various domestic appliances in your house.

Appliance Electrical Consumption
Electric Shower 9000 Watts
Electric Cooker 3000 Watts
Washing Machine 2500 Watts
Tumble Dryer 4000 Watts
Kettle 3000 Watts
12kw Ground Source Heat Pump 1500 – 2500 Watts (See Image Below)

Another issue the power providers concern themselves with is Start Up Current. However with a modern Inverter Copeland Compressor, the Start Up Current is as low as 6 Amps (Click on our You Tube Video Below to view this). The Start Up Current of a Hotpoint Electric Built in Oven is 10 Amps. Also a number of our previous clients run their heating system at night when you get electricity at less than half price for 7 Hours which means that the heat pump has an even less impact on Power Providers Network.

So in a nutshell, our heat pumps when designed and installed correctly with high COP’s perform very well and use very little electricity. If your power provider is making a scaremongering claim about lights dimming when the heat pump starts up, please send them a link to this blog!