The primary difference between a ground source heat pump and a conventional boiler is that a conventional boiler is usually designed to heat the property between certain hours. It achieves this by outputting an enormous amount of heat over a short space in time. The property heats up, the boiler switches off and the house goes cold again.

A ground source heat pump works differently to this. The ground source heat pump does not like producing very hot water. A conventional boiler might output water to your radiators at a temperature in excess of 70 degrees C. A heat pump can achieve this but it would be inefficient in doing so.

Therefore the style of heating needs to be changed to accommodate lower temperature heat output.

In general this means using underfloor heating (running at a low temperature, perhaps 38 degrees C) or radiators that are oversized so that they can run at a lower temperature than normal (perhaps 50-55 degrees C).

When the output temperature of the system is lowered it is vital that this heat is retained as the time taken to heat the whole building will increase.

The key to a good ground source heat pump installation is insulation. Great insulation will benefit any home, whatever the type of heat system. However, for a ground source heating system to operate without a back up it is vital. This will provide the property owner with a very efficient and cost effective heating system.

Air Source Heat Pumps

Air source heat pumps work in a similar way to ground source heat pumps but extract heat from the air outside rather than the ground. They upgrade this heat using a compressor circuit (similar to that found in a fridge).

Typically over a year an air source heat pump could have an efficiency of around 330% when heating a domestic home (including domestic hot water). This means that for every unit of electricity that it uses it generates 3.3 units of heat.

A modern high efficiency gas boiler has an efficiency of around 90%. This massive efficiency advantage means that the system will save you money off your fuel bills.

Comparing the system to a gas boiler you should save around 30%. Given the cost of oil, when replacing an oil boiler the savings can be up to 60%.

This type of heat pump can also be used for heating swimming pools.

Ground Source Heat Pump vs Air Source Heat Pump, which is right for me?

The difference between these systems is that Air Source Heat pumps do not need a ground loop , they extract heat from the air around us. The disadvantage with an air heat pump is that as the ambient temperature outside decreases, the air heat pump becomes less efficient at extracting the heat.

One other fact of central heating systems is that you need them most when the outside temperature is at it's lowest. This means that air heat pumps are useful for heating properties that don't have the room or funds for a ground loop or need heat when the ambient temperature is generally higher. This means that air heat pumps along with unglazed solar water panels are very useful for heating swimming pool water.

In summary, if you want to heat your home efficiently with electricity, consider a heat pump. If you have a ground source heat pump you will benefit from good efficiency all year round.

Given that the major consideration between these two technologies is the annual efficiency, it is worth knowing that a ground source system could have an efficiency of around 450% when an air source system would be about 350%.