Application to the home

Before considering a heat pump system for your home, there are a few fundamental conditions to be taken into account:

• is the required heating system individual or collective?
• does the existing system need to be replaced?
• is it cost effective to consider a renewable energy source?
• is a heat pump installation possible for your home?

Effect of climate

The amount of renewable heat that can be supplied for a given size of heat pump system depends upon the geographical location of the dwelling as well as its heat loss. As the UK is an island and has a maritime climate, neither very cold nor very hot temperatures are experienced although the further north you live, the longer is the length of the heating season as shown in the graph below.

This type of heating requirement is ideal for a heat pump as it tends to operate continuously rather than being cycled on and off. This suggests that the heat pump systems will be very efficient in the UK and the potential is very large.

Environmental impact

The biggest environmental impact is that associated with generation of electricity from fossil fuels which results in the production of average carbon dioxide emissions for the UK of 0.41 Kg/kWh electricity. A comparison of the CO2 output per kWh heat is given in the table below from which it can be seen that heat pumps produce less CO2 than other heat sources because of their high efficiency and ability to concentrate renewable heat. Note that if the electricity was generated from renewable sources, there would be no environmental emissions.

The other potential impact is from the ground collector where it is possible to obtain infiltration of the ground water by brine solution if the collector pipe is damaged or leaks.