By: John Gibbons

Mention the word ‘geothermal’ in civilised company these days and you are more than likely to be treated to a wide range of opinions and information on the merits, or otherwise, of installing a home heating system that takes heat from deep underneath the surface of the earth.

If we look at geothermal energy at its most basic, the concept couldn’t be simpler. In fact, geothermal energy has been with us since time began. From our earliest geography lessons in school, we all know that heat is stored underneath the surface of the earth. Extracting some of this heat from the ground and using it to heat our homes and our domestic hot water systems seems like a very obvious solution to our heating needs as we move towards a future which must place a lot less dependence on fossil fuels and a lot more on renewable forms of energy.

Heat is supplied to the ground from two main sources, namely the hot core of the planet and the sun. It is the second source of heat to the ground – radiation from the sun – which is extracted for use in geothermal heating systems.

When we consider that solar thermal radiation is being absorbed by the surface of the earth day after day and stays relatively warm throughout the year, we can see that we are walking around on a vast, (and largely untapped) source of heat every day of our lives.

So how does geothermal heating work?
If we think of the surface of the earth as being like a huge solar collector, we can perhaps begin to understand the potential of geothermal energy. In Ireland, the ground maintains a constant temperature between six and 10 degrees Celsius. Geothermal heat pumps extract this heat and use a compression system to pump up the low temperatures and release them at a higher temperature to be used in domestic hot water and heating systems.

Won’t my electricity bill go sky-high?
Geothermal heat pumps are powered by electricity, but one of the most important aspects to remember about this system is that, for every single unit of electricity used to operate the heat pump, up to four units of heat are generated. Your electricity bill will undoubtedly be higher, but you must balance this against the cost of heating your home previously, perhaps through the use of gas, oil or turf.

For example, think of the annual bill to your oil or gas supplier…then halve it…….and that will roughly be the cost of your electricity bill.

How much does it cost?
Installing a geothermal heating system can cost in the region of 11–13,000 euros, so it is not a decision to be taken lightly. The Government-backed “Greener Homes Scheme” operated by Sustainable Energy Ireland offered a very attractive grants package for the installation of geothermal systems.

These grants were slashed recently, but it is hoped that pressure on the Government parties will result in a re-instatement of the full grants package (in excess of 4,000 euros) for heat pumps.

The purchase and installation of a ground collector for your geothermal heating system forms the bulk of the initial outlay, but despite the seemingly high cost of installing a geothermal system, it still remains one of the most energy efficient and cost effective heating systems available.

When being quoted a price for a geothermal heating system, the key word to focus on is installation. There is a wide variation in the price of heat pumps, but remember that the heat pump itself is just one component of the overall system. You must look at the overall price of the fully-installed system.

It is wise to allow yourself between six and 10 years for a payback on your geothermal heating system.

What does the system consist of?
A geothermal heating system has three main components: a series of pipes in the ground; a heat pump and a heat distribution system. Two myths about geothermal systems are:
a) that you need a huge garden and
b) there will be massive disruption of your site during the installation process.
Neither of these widely-held beliefs are true. Installation takes no more than three to four days, and once the system is up and running it requires very little maintenance and has a long life expectancy.

What do I do first?
If you are building a new house, you should submit your plans to a reputable geothermal supplier who will prepare a costing and carry out a detailed on-site inspection to see which system is best suited to your needs. Clients who wish to install a heat pump in an existing house should also request an on-site inspection to assess the suitability of a geothermal heating system.

Geothermal heating is safe, green, cost-effective, very discreet and grant-aided. What are you waiting for? For more information contact: www.energysuperstore.ie