THE HIDDEN BENEFITS OF GOING TO
GROUND
Geothermal energy is an earth-moving answer to the energy crisis, finds Mark Keenan. You might not want to read the following piece — because it’s about a complex heating system. But chances are you wouldn’t mind saving €700 per year in heating costs, so read on. Because it’s relatively new in Ireland, and because there are so many types and variations to comprehend, geothermal heating is probably the most complicated of all the renewable energy systems to understand. Added to that, it’s also hugely expensive to install. Geothermal heating can set you back between €6,000 and €20,000 all in. At that rate, it could take more than a decade for some systems to pay for themselves. Worse still, because it’s so expensive and because most people know so little about it, anybody who wants to install
a system may find themselves at the mercy of inexperienced installation crews or conmen. “I would say that if you are installing geothermal heating today, you are quite likely to be stung in one way or another,” said one industry insider who did not want to be named. “The most common scam is to charge you the price of a large pump for a smaller one. The culprit turns it up full so it looks like it’s doing the job of a larger model.” Then there’s the cost of the ineptitude which comes with a reasonably new system of any kind. “Poor training results in unsuitable machinery and components being installed — the wrong heat-exchangers for the size of the home, and so on,” says our insider. Despite being such a complete minefield for the unwary homeowner, one thing is certain: geothermal heating is the future. And we’d better get our heads around it. Geothermal heating can be installed just about anywhere. Although there are no figures available, perhaps half of all new one-off rural homes are now built with a geothermal system. All users claim that their energy bills have been slashed. A further advantage is that you can apply for a government grant of between €2,500 and €3,500 towards the cost of installation of a geothermal heat pump. The budget speech suggests that further grants may be on the way to help cut the higher cost of fitting existing homes with a geothermal system. So what is it, how much does it cost and are householders happy with it? What is geothermal heating? Geo means “of the earth”. The ground itself exudes heat at two levels: down deep, closer to the planet’s molten core, and near the surface, where the warmth of the sun shining on the ground is retained. To heat a home, this “free” heat needs to be (a) extracted, (b) boosted or amplified and (c) transferred to the house. The whole process is powered by electricity and usually, but not always, involves a heat pump. The big advantage is that these combined processes, once installed, are far cheaper to run and consume far less fossil fuel than a traditional oil or gas system. A geothermal system starts boosting or amplifying heat from about 12C (a fairly usual Temperature for ground harvested heat) which means you have far less power to burn in boosting it to a useable level (say 26C) than a conventional system which may have to boost from 0C in winter. A shallow-heat system gathers energy from near the surface through a receptor grid — usually at a depth of about one metre. The grid, which runs in continuous loops (like the tubing found at the back of a fridge) is filled with fluid which conveys this natural heat to an electric heat pump, which in turn boosts this heat, normally by between one to five times. This boosted heat is then run through the house via underfloor heating pipes. Less common in Ireland, but necessary in built-up areas where land is limited, is the “deep-bore” ground system such as the one specified by Odos Architects when it designed new rear extensions for two houses in Rathmines, Dublin 6. This is more expensive because it involves hiring a well-drilling firm to dig a hole deep enough (about 500ft) to sink the heat receptors. Once the drilling is done, the system then works in the exact same way. Both of these systems can also transfer the energy from the ground to a heat storage water tank, precluding the need for a heat pump. Heat can be transferred to the tank during the night, then used in the day, saving even larger amounts of money through the use of discounted rates for electricity at night. The third-most common geothermal system in Ireland uses electricity to boost the naturally occurring heat in the air, like a reverse air-conditioning system. Because of their low cost, air systems are closest to being Adopted by the construction industry for new estates. What are the advantages of geothermal systems? Once the system has been put in place it generally pays for itself within four to eight years depending on whether a home is new or has been retrofitted, the latter process being significantly more expensive (from €15,000 upwards). You could, over a period of 20 or 30 years, save tens of thousands of euros. Combined with other measures such as solar, heat exchange and highly efficient insulation, you could reduce your overall fuel bill to a few cents a day. What are the disadvantages of geothermal energy? Geothermal represents a hugely expensive initial investment. It’s not yet clear how much an installed system adds to the value of a home when it is put up for resale. Geothermal can only run underfloor heating, not radiators. Thus it cannot be turned up and down on a whim, and you can be caught out by, say, a sudden cold snap in the summer because it takes days for the system to readjust. The cost can often be unpredictable — deep-bore could be very much more expensive if you hit bedrock for example — something you won’t know until drilling commences. What does it cost to install? Estimates vary widely from €6,000 for an air system in a new home to perhaps €25,000 for a retrofit deep-bore in an older home. How muchwill it save me? Larger homes have the best cost savings. Combined with high insulation levels, it should shave 30% or more off your heating bill. That’s €700 a year for an average home. And that’s at today’s gas and oil prices. Gas is already going up again. Oil is likely to follow in time. What do people who have installed geothermal systems say? Hugh Mulcahy, who had a shallow ground system installed four years ago, says: “Compared with my old house which was a similar size and powered by oil, my fuel bills are greatly reduced. My new home is timber-frame and I had it insulated way above average which has amplified the effects of the geothermal. My monthly heating and hotwater now costs €38 per month.” John and Joanne Jankunas completed their 3,0000-sq-ft home at Ballintogher, Co Sligo, a year ago, and spent €40,000 on installing a number of devices including double-requirement standard insulation, multifuel stoves, a windmill, rainwater recovery system and a shallow ground geothermal heating system. Jankunas says the total power bill for his home is 70c per day. “That’s unlikely to change too much, whatever the cost of gas and oil,” he added.
Geothermal energy is an earth-moving answer to the energy crisis, finds Mark Keenan. You might not want to read the following piece — because it’s about a complex heating system. But chances are you wouldn’t mind saving €700 per year in heating costs, so read on. Because it’s relatively new in Ireland, and because there are so many types and variations to comprehend, geothermal heating is probably the most complicated of all the renewable energy systems to understand. Added to that, it’s also hugely expensive to install. Geothermal heating can set you back between €6,000 and €20,000 all in. At that rate, it could take more than a decade for some systems to pay for themselves. Worse still, because it’s so expensive and because most people know so little about it, anybody who wants to install
a system may find themselves at the mercy of inexperienced installation crews or conmen. “I would say that if you are installing geothermal heating today, you are quite likely to be stung in one way or another,” said one industry insider who did not want to be named. “The most common scam is to charge you the price of a large pump for a smaller one. The culprit turns it up full so it looks like it’s doing the job of a larger model.” Then there’s the cost of the ineptitude which comes with a reasonably new system of any kind. “Poor training results in unsuitable machinery and components being installed — the wrong heat-exchangers for the size of the home, and so on,” says our insider. Despite being such a complete minefield for the unwary homeowner, one thing is certain: geothermal heating is the future. And we’d better get our heads around it. Geothermal heating can be installed just about anywhere. Although there are no figures available, perhaps half of all new one-off rural homes are now built with a geothermal system. All users claim that their energy bills have been slashed. A further advantage is that you can apply for a government grant of between €2,500 and €3,500 towards the cost of installation of a geothermal heat pump. The budget speech suggests that further grants may be on the way to help cut the higher cost of fitting existing homes with a geothermal system. So what is it, how much does it cost and are householders happy with it? What is geothermal heating? Geo means “of the earth”. The ground itself exudes heat at two levels: down deep, closer to the planet’s molten core, and near the surface, where the warmth of the sun shining on the ground is retained. To heat a home, this “free” heat needs to be (a) extracted, (b) boosted or amplified and (c) transferred to the house. The whole process is powered by electricity and usually, but not always, involves a heat pump. The big advantage is that these combined processes, once installed, are far cheaper to run and consume far less fossil fuel than a traditional oil or gas system. A geothermal system starts boosting or amplifying heat from about 12C (a fairly usual Temperature for ground harvested heat) which means you have far less power to burn in boosting it to a useable level (say 26C) than a conventional system which may have to boost from 0C in winter. A shallow-heat system gathers energy from near the surface through a receptor grid — usually at a depth of about one metre. The grid, which runs in continuous loops (like the tubing found at the back of a fridge) is filled with fluid which conveys this natural heat to an electric heat pump, which in turn boosts this heat, normally by between one to five times. This boosted heat is then run through the house via underfloor heating pipes. Less common in Ireland, but necessary in built-up areas where land is limited, is the “deep-bore” ground system such as the one specified by Odos Architects when it designed new rear extensions for two houses in Rathmines, Dublin 6. This is more expensive because it involves hiring a well-drilling firm to dig a hole deep enough (about 500ft) to sink the heat receptors. Once the drilling is done, the system then works in the exact same way. Both of these systems can also transfer the energy from the ground to a heat storage water tank, precluding the need for a heat pump. Heat can be transferred to the tank during the night, then used in the day, saving even larger amounts of money through the use of discounted rates for electricity at night. The third-most common geothermal system in Ireland uses electricity to boost the naturally occurring heat in the air, like a reverse air-conditioning system. Because of their low cost, air systems are closest to being Adopted by the construction industry for new estates. What are the advantages of geothermal systems? Once the system has been put in place it generally pays for itself within four to eight years depending on whether a home is new or has been retrofitted, the latter process being significantly more expensive (from €15,000 upwards). You could, over a period of 20 or 30 years, save tens of thousands of euros. Combined with other measures such as solar, heat exchange and highly efficient insulation, you could reduce your overall fuel bill to a few cents a day. What are the disadvantages of geothermal energy? Geothermal represents a hugely expensive initial investment. It’s not yet clear how much an installed system adds to the value of a home when it is put up for resale. Geothermal can only run underfloor heating, not radiators. Thus it cannot be turned up and down on a whim, and you can be caught out by, say, a sudden cold snap in the summer because it takes days for the system to readjust. The cost can often be unpredictable — deep-bore could be very much more expensive if you hit bedrock for example — something you won’t know until drilling commences. What does it cost to install? Estimates vary widely from €6,000 for an air system in a new home to perhaps €25,000 for a retrofit deep-bore in an older home. How muchwill it save me? Larger homes have the best cost savings. Combined with high insulation levels, it should shave 30% or more off your heating bill. That’s €700 a year for an average home. And that’s at today’s gas and oil prices. Gas is already going up again. Oil is likely to follow in time. What do people who have installed geothermal systems say? Hugh Mulcahy, who had a shallow ground system installed four years ago, says: “Compared with my old house which was a similar size and powered by oil, my fuel bills are greatly reduced. My new home is timber-frame and I had it insulated way above average which has amplified the effects of the geothermal. My monthly heating and hotwater now costs €38 per month.” John and Joanne Jankunas completed their 3,0000-sq-ft home at Ballintogher, Co Sligo, a year ago, and spent €40,000 on installing a number of devices including double-requirement standard insulation, multifuel stoves, a windmill, rainwater recovery system and a shallow ground geothermal heating system. Jankunas says the total power bill for his home is 70c per day. “That’s unlikely to change too much, whatever the cost of gas and oil,” he added.