Questions & Answers On Heat Pumps
Questions & Answers About Ground Source Heat Pumps
How efficient is a ground source heat pump system?
Ground Source Heat Pumps are very energy efficient. For each kilowatt of electricity used to run the Ground Source Heat Pump, three to four kilowatts of thermal heat are delivered to the building.
I haven't heard of these systems before, are they new?
In the United States and Europe, especially Sweden, Austria and Germany, the use of Ground Source Heat Pumps (GSHP) is very common. The ground source heat pump was invented more than fifty years ago, and continuous development has greatly improved its reliability and efficiency. It is a proven, safe and cost-effective.
How big is a heat pump?
A typical heat pump unit for a domestic installation is about the same size as a tall fridge.
Can it supply hot water for the house?
The heat pump will heat the water to 50*C and once weekly a boost will heat the water to 65*C to clean the water of any bacteria.
What maintenance is required on the Heat Pumps?
Your heat pump will operate efficiently for many years with minimal attention. Although no scheduled maintenance is required, it is important to check that the two strainers are clean. One strainer is fitted to the ground loop and one to the heating system. In the “C” Series models the two strainers are external to the unit. In the “E” Series models the strainer for the heating circuit is contained within the unit. If either of these is dirty then the heat pump will shut down. On a new heating system the strainers may need regular cleaning until all debris has been removed.
Can the systems provide cooling?
Some heat pumps do provide heating and cooling but there are no grants for these systems.
Can I use a standard domestic electricity supply or does it have to be 3 phase?
Single phase is fine for most domestic heat pumps. Three phase would be essential for larger units.
Is a Heat Pump suited to new builds?
Very well suited. The insulation values on new builds make the installation of heat pump a good choice. It's cheaper when installing on a new build and the installation of the ground loops can be done when the footings are excavated.
Does a Heat Pump work with UFH?
Heat Pumps are perfect for underfloor heating systems because Underfloor Heating operates at a low temperature.
Will a GSHP work in an older property with rads?
If the property is well insulated and the rads are large enough then yes you should be able to install a heat pump. The rads that would of been sized for your existing gas/oil boiler would be oversized and generally a heat pump will be able to use them without changing them. Upstairs is usually less of a problem as bedrooms are normally kept at lower temperatures.
How much will a Heat Pump cost to install?
You will be looking at a fully installed price of £12,000+
Are there grants available for Ground Source Heat Pumps?
The grant available through Green Systems UK is £1,500. More than through the goverment grant scheme which only offers £1,200.
Could I install the heat pump outside in my garage or basement?
Usually this is no problem, the heat pump must be kept dry, it shouldn't be installed where water damage might occur.
What are the options for the ground loops or ground collectors in the garden?
A typical heating-only installation for a medium sized, new build detached house would need at least two narrow trenches, each 300 mm wide and 40 to 50 metres long and 1 metre deep. The trenches can be straight or curved and laid in any direction to suit your site, providing they are always a minimum of two or three metres apart. A mechanical digger, such as the type used to dig conventional foundations and footings, can dig the trenches and backfill them after the ground loops have been installed. Your builder and/or digger driver will be able to do this work and plan it to ensure the minimum of disruption to your site. Once completed, and the ground loops pressure tested and buried, your renewable energy collection system can basically be forgotten.
We have a garden but very big trenches are not suitable, what now?
The trenches for this installation need to be 3m deep and as narrow as can be made. If more than one trench is specified, there needs to be at least 3m separation between them. The number of panels in each separate trench must be limited to 10 and there must be the same number of panels in each trench. As long as the length of trench specified in the quotation is maintained, the trenches do not have to be straight, they can change direction by 90°. The pipe from the end of the last panel must be sloped round in a minimum 500mm radius and can be lead back along the top of the panels to the beginning of the trench. The panels are made from 40mm pipe and need to be connected together. The trenches are then filled with soft sand.
My garden is very small, is it still possible to install ground loops?
For these systems a borehole or boreholes are drilled. The diameter of the borehole should be at least 125mm. A trench will also need to be dug from the house to the boreholes. This needs to be 1m wide and 800mm deep. If this depth cannot be achieved then the pipes must be insulated back to the heat pump. The depth of bore hole is as specified in the quotation. If more than one borehole is specified, there needs to be at least 5m separation between them. The pipe work will be delivered the correct length to fit into the drilled holes and will have ‘U’ bends attached. These will need to be inserted into each borehole and backfilled with ‘bentonite’ grout.
My land is very wet, can I use this?
Wet land is better at conducting heat so the wetter the better.
We're using electricity, are GSHP systems really renewable?
If your using fossil fuelled electricity to power your heat pump, no not really. You need to get your electricity from a green electricity provider, if you use this to power your heat pump, your property will be totally heated from renewable energy with zero carbon emissions.
Can I dry out my new build property with a heat pump?
The heat pump is not designed or sized to provide the greatly increased heat demand during the initial drying out of a newly constructed building. During this period, and until the building is completely finished, supplementary heating may well have to be supplied by the owner/builder using separate equipment.
What are the guarantees with the system?
Five years full guarantee, extendable to ten years.
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