FAQs
Can you summarise the advantages of geothermal heating, which I am considering for my indoor pool.
Geothermal heating utilises the available heat within the ground, using heat pump technology, to provide heating for pool, spa, pool room and also hot water for shower and basins.
Will geothermal be the only source of heat?
We recommend that off-peak electric heating is available for exceptionally cold winter conditions. To date we have found that this back-up source is seldom used except for boosting initial heating, whilst the indoor pool is being commissioned.
The heating source of our house is oil, what savings am I likely to make if I choose geothermal for my indoor pool.
Geothermal heating will reduce heating costs when compared with an oil fired boiler, by approximately 50%.
What is the payback period?
Based on current fuel costs, the cost of the geothermal installation is likely to be recovered within approximately 10/12 years taking into account both the cost of the complete geothermal installation and the savings from not having to install an oil fired boiler.
Is the equipment reliable?
Geothermal heating utilises heat pump technology on a reverse fridge principle and is relatively low tech.
How are such dramatic savings possible?
Whilst the heat pump requires electricity, it provides what is referred to as a “Coefficient of Performance" of 4:1.
Surely the heat in the ground is insufficient to provide sufficient heat for my swimming pool.
At approximately 5m depth the ground has a constant heat of 12/14°C. This will be boosted to 45/55°C by the geothermal heat pump, which will be adequate for heating your pool.
What is involved in the excavation works?
Approximately four boreholes will be specified to a depth of 75m-100m. Alternatively trenches accommodate geothermal loops.
Do the boreholes have to be close to the swimming pool?
The boreholes ideally should be situated approximately 7m apart and can be positioned where convenient. High specification insulated pipework is used, which ensures that virtually no heat loss occurs through the pipework between geothermal boreholes and plant room.
How big are the boreholes and will they be evident upon completion of the installation.
The boreholes are approximately 150mm in diameter and, after the site has been re-landscaped, there will be no evidence of the boreholes.
Are some ground conditions more suitable for geothermal heating than others?
Almost all ground conditions are suitable for geothermal heating. It is sometimes necessary to provide sleeves within the boreholes, in order to contain the insulated grout, which surrounds the flow and return pipework.
How can you anticipate whether soil conditions are suitable for geothermal heating
Prior to the commissioning of a geothermal scheme, extensive research and geological information is gathered as to the likely soil conditions for the site in question. This will form the basis of the cost for the boreholes included with the overall geothermal quotation.
What happens if bedrock is found?
The majority of sites are suitable for geothermal. Should bedrock be encountered the decision may be taken to excavate a greater number of boreholes to a shallower depth, or use the “Slinky” horizontal pipe method.
Do you recommend horizontal ‘Slinky’ geothermal?
Some ground conditions are more suited to horizontal trenches than deep bore piling. This method can be more economical, although the re-landscaping cost of the extensive area required, will have to be taken into account.
What happens if ground water is encountered ?
Water is a good conductor of heat and the presence of ground water is usually beneficial.
How is the geothermal heating harnessed to provide heat for my swimming pool water?
A geothermal-compatible heat exchanger similar to the heat exchanger, which would have been installed for a conventionally-heated pool, will be used. The difference is that there is a larger heat exchanger providing an output temperature of 45/55°C in comparison to 60°C to 70°C for a conventional boiler system.
How is the heating controlled to provide heating within my pool room?
Heat will be provided for the pool room through underfloor heating, which will be laid over all floor areas within the pool room and adjacent areas. Pool room heating is also achieved through the air handling system, which will provide dehumidification and ventilation.
Will geothermal heating provide sufficient heat for a spa?
Yes, although the initial heating-up period is longer due to the lower input temperature. Often the spa is covered, when not in use, and its higher temperature is maintained by geothermal heating. Alternatively, an additional conventional heater can be provided to ensure quick heating whenever required.
Will my plant room need to be substantially larger due to my having geothermal heating?
The geothermal equipment is likely to occupy approximately 4m/sq within the plant room.
Will the system operate based on a standard 100amp electrical supply?
The total electrical load for an indoor pool must be considered. The geothermal installation is likely to require 4/8Kw.
What controls are utilised in order to minimise running costs?
Water will only be circulated through the geothermal boreholes to harness additional heat, when it is required. The water circulation system is similar to a standard LPHW boiler system. When the desired set point heat has been achieved within the pool room, pool and spa, the geo thermal circulation system automatically switches off. The circulation pumps operate on a variable speed basis to provide just sufficient heat, without excess electricity being used to operate the pumps.
What would an average indoor pool require in terms of daily electrical use?
Recent indoor pool geothermal installations have indicated that this can vary between 100/150kw/hrs a day depending on the time of year and usage.
From what you say, why isn’t everyone having geothermal heating for their new indoor pools?
For geothermal heating to be considered, the clients would be anticipating remaining at the property for a number of years. However, houses which include geothermal heating, will be more valuable than comparable houses with conventional heating.
Would you say your ten to twelve year anticipated payback period is conservative?
It is generally accepted that heating costs will rise substantially in future and this may cause an accelerated payback period. It is also highly likely that carbon taxes will be introduced, which will tax the use of fossil fuels.
Are Grants available for the installation of geothermal heating?
Presently, grants are minimal. It is possible to claim up to one third of the cost of the installation, or £1,000/£1,250 whichever is the lesser!
Do Local Authorities encourage use of geothermal?
Building Regulations require a high degree of insulation within new buildings and restrict the area of glazing. However, many highly specified contemporary modern buildings are designed with extensive glazed areas. If geothermal heating is specified, substantially larger areas of glazing can be specified.
What service does your company offer?
We provide a comprehensive service on a turnkey basis to include the entire installation – ground works, pipework, equipment, controls and full commissioning.
Do you provide a fixed price quotation?
All works within the plant room are quoted on a fixed price basis. The geothermal boreholes are quoted at a fixed price based on the soil conditions anticipated within our survey report. Should soil conditions differ from those anticipated, additional costs may apply.
How would you summarise the justification for using the SPEC Ltd?
SPEC Ltd specialises in geothermal heating for indoor pools. We have commissioned a number of successful schemes and will offer a total service. Swimming Pool-Design Ltd our sister company will specify all areas of interface with other works. Overall, you will find our service is tailored to suit your specific requirements and is comprehensive.
In addition to the geothermal for my new indoor pool would you also connect the system into underfloor heating within various areas of my house?
We do not undertake geothermal heating for new houses as a stand-alone contract but, subject to an indoor pool geothermal system being required, we should be pleased to ensure that this is specified and connected into your house heating system.
How does geothermal compare to solar heating?
Solar heating is most effective in warm sunny conditions and our experience is that it will not provide sufficient heat for the year round use of an indoor pool. Solar heating can be used as an effective addition to outdoor pool heating.
Do you recommend the use of air to water heat pumps for outdoor pools?
High specification heat pumps are usually effective in providing total heating of an outdoor pool, subject to the application of a thermal heat retention cover, when the pool is not in use. A maximum water temperature of approximately 28°C sometimes dictates the use of an electric heater using off-peak electricity, a dedicated pool oil or gas fired boiler or utilising the house boiler.
What about air heating from a heat pump for an indoor pool?
It will also be worth considering the use of air collectors, which will utilise the 1:4 Coefficient of Performance of the heat pump, to provide economical heating with a conventional heat back up.
Do you recommend air collector technology as against geothermal?
The average air temperature winter and summer (24 hours per day) is approximately 10°C in the UK. When the temperature is below 10°C the air collector will be less efficient than the constant heat source from the ground. However the cost for air collectors will be less as boreholes are not required. A back-up heat source is recommended for an air collector system – either off-peak electric heating, oil or gas fired boiler.
Please summarise the service offered by SPEC.
We offer technical expertise for the provision of heating for indoor and outdoor pools . We will discuss a potential scheme with clients and will provide detailed recommendations regarding energy efficient heating. This will include the full cost for the works, although we usually liaise with the client’s contractor, who provides building enabling works for the energy efficient heating system. Detailed working drawings will be provided for all aspects of the work.
