Ground Source Heat Pumps, also known as GSHPs, are often touted as one of the best heating systems going. They’re efficient, low emission and long lasting. If you’re looking for a cheap energy source, you don’t have to look any further than the ground beneath your feet! In this guide we’ll break down how they work and whether a GSHP could be the answer to your home heating needs.
GSHPs are a system for heating your home using the warmth generated in the ground outside your property. The system operates by driving water around a loop of pipe, and then into a condenser unit.
The heat from the ground outside the pipe, which rests between 10ºc and 13ºc, is transferred into the pipe, raising the temperature slightly. A condenser increases the temperature of the water further, to heat a refrigerant. At this point the temperature is higher than room temperature and this heat is transferred into your house’s wet heating system, for example your radiators or underfloor heating system.
Having transferred it’s heat, the Heat Pump system releases its cooled water back into the ground loop, to be warmed again.
There are two common types of GSHP, and the one you require will largely be dictated by the size of the outdoor area available on your property. A Horizontal GSHP has it’s underground loop close to the surface, and over a large surface area. This could be beneath a large square area or a long garden, but generally they take up at least a ½ acre of land. Larger properties will require even more space. Horizontal GSHPs are more common in rural areas where average property size is larger, and are generally more cost effective to install than their vertical counterparts.
This is because Vertical GSHPs, the other common type, are generally very expensive to install. The underground component is bored directly downwards as opposed to in a shallow trench, and the bore hole can be anywhere from 50m to 150m. Vertical GSHPs are more common in suburban properties where land availability is lower, however they are still limited by the requirement to use large machinery on the property.
For every KW of electrical energy required to run a GSHP system, around 4 KW of useful heat energy is generated. This ratio is known as a heating systems coefficient of performance (useful output kw/ input kw). GSHPs have a rating between 3 and 4 for the most part, which is extremely high compared to most home heating systems. This efficiency, compared with the fact the source of energy required for the system, sunlight heating the ground, is almost constant year round, means a GSHP will be efficient at all times.
GSHP systems can be highly efficient in tandem with good quality insulation and draught exclusion.
They also require small amounts of electricity to run. In many cases this could be provided by renewable energy such as solar, allowing an extremely low emission system overall.
GSHPs are very efficient but other Heat Pumps, such as Air Source Heat Pumps, have some benefits. The main positive to an Air Source Heat Pump is the lower installation costs incurred. They can be less than half the up front cost! Use our guide on Air Source Heat Pumps to learn more!
It’s a good idea to weigh up the savings you could make between different heating systems, as this will vary greatly based on which system you will be changing from. Run an energy comparison to compare energy suppliers and systems, and make a note of which set up could save you most!
For an average family household, around 700m² of available land is required for a GSHP, so if you don’t have this much at least a Ground Source Heat Pump will become expensive. You will need to install vertically, meaning you’ll have to pay the higher up front fees and hire specialist machinery. In these instances and Air Source Heat Pump could be a better option.