Geothermal Heating Explained

Humans have been using geothermal heating since the Stone Age, but what exactly is geothermal heating, and how can your home benefit?

Geothermal heating relates to using the ground to transfer heat to your home. As outdoor temperatures naturally fluctuate with the changing seasons, underground temperatures don’t change as severely due to the insulating properties of the earth. At four to six feet underground, temperatures remain reasonably constant all year round.

Inserting a series of small pipes into the ground, called an earth loop, allows for this heat to be transferred to and from your home, essentially creating “free” energy. In this process, heat is not created—it is transported, meaning no fuel is burned.
Geothermal heating systems require little maintenance, and when installed properly, the buried earth loop can last for generations. Other components (which are housed indoors) are protected from the elements, so are also able to last for a number of years, often decades. The only required maintenance with a geothermal system is sporadic checks and filter changes, and annual coil cleaning.
A geothermal heating system has two main components: the heat-pump (the indoors unit) and the earth loop (underground pipes connected to the heat-pump). Some systems will also have an air delivery system, or radiant heating.
Most heat pumps have efficiencies rated based on their coefficient of performance (COP). It’s a scientific method of determining how much energy the system provides, versus how much it uses. Most geothermal pump systems have COPs of 3.0 to 5.0, meaning that for every unit of energy used to power the system; three to five units are supplied as heat.

Top 5 benefits of geothermal heating
1. Low operating cost
The most efficient gas furnace will have an energy rating of 94 per cent—geothermal systems have a 400 per cent rating. As geothermal systems transfer heat instead of creating it by burning other fuels, they are far more energy efficient—resulting in lower fuel bills.

2. Peace and quiet
Unlike air conditioners or heat pumps, there is no outdoor unit required. Geothermal units run very quietly during operation.

3. Safe, clean air
There is no combustion in a geothermal heat pump, meaning there is no possible chance of carbon monoxide poisoning. By adding high efficiency air cleaners with geothermal, a high quality of indoor air can be achieved.

4. Sound investment
For many retrofit applications, and especially new construction, the energy savings more than offset the cost of installation even over a short period of time. Geothermal units will produce energy savings, which will equal (and subsequently exceed) the cost of the system installation over a period of time.

5. Environmentally conscious
Geothermal systems are recognized as the most environmentally friendly method to heat (and cool) a home. Unlike other systems, the geothermal system does not produce carbon dioxide, carbon monoxide, or other greenhouse gasses which contribute to air quality pollution. The low electricity demand from geothermal systems helps to reduce the need for more electricity generating plants.

Is geothermal heating right for you?
Before making any commitments to installing geothermal heating in your home, there are some key questions to consider:
Is your garden suitable for an earth loop? Your garden doesn’t have to be particularly large for the earth loop, but the ground needs to be suitable for digging a trench or borehole, and be accessible to digging machinery.
Is your home well insulated?
Heat pumps work best when producing heat at a lower temperature than traditional boilers. It’s essential that your home is well insulated and protected against draughts (see p.00) for the heating system to be as effective as it can be.
What fuel will you replace?
The system will pay for itself quickly if its replacing electricity or a coal heating system. However, heat pumps may not be the best option for homes using mains gas supply.
What type of heating system will you use?
Ground source heat pumps perform better with under floor heating systems or warm air heating than with radiator-based systems due to the lower water temperatures requires.
Is the system only for new developments?
Combining the installation with other building work can reduce the cost of installing the system. If you do choose to install the geothermal unit to your home, the cost of installation is justified considering the long-term savings. 

Financial support
You may be eligible to receive payments for the heat you generate using your geothermal system through the UK Government’s Renewable Heat Incentive (RHI). For more information, visit: energysavingtrust.org.uk

Image courtsey of Kensa Heat Pumps Ltd. 

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