Last week I reviewed the merits of hydroelectric systems as a way to generate your own energy. The obvious conclusion reached is that whilst hydroelectric systems are potentially a great option if you have a river or stream running along the bottom of your garden, most of us do not have the benefit of living at such a property.
This week I review the merits of ground source heat pumps. Such systems have the potential to benefit many of the UK's more modern homes, especially if installed at the same time as delivering a home extension or major home renovation.
How do ground source heat pumps work?
Ground source heat pumps use a loop of pipe, which is typically laid under your garden, to obtain heat from the ground. This heat is turned into hot water in a water cylinder. The hot water is then used to heat your home.
How much energy will a ground source heat pump generate?
The amount of water that can be heated by a ground source heat pump depends on the length of the ground loop. The longer the loop, the greater the amount of heat that can be recovered from the ground.
What are the advantages of ground source heating?
When installed as part of an integrated heating system in a modern home, ground source heating will reduce your heating bills.
Heat pumps can be used in tandem with underfloor heating and other energy saving technologies to dramatically reduce your energy bills.
Whilst disruptive to install, once in place, ground source heat pumps are efficient and long lasting.
Another benefit of heat pumps is that they double up as cooling devices, and can be used to maintain a comfortable temperature in your home on warm summer days.
Are there any constraints?
The longer the loop, the greater the amount of heat that can be recovered from the ground, but longer loops need more space to be buried in. However, there is the option to dig downwards where space is limited.
The biggest constraint is often the ability of accessing your garden with the digging equipment. Installation of the pipes involves digging trenches, which can make a mess of your garden. Ideally, to limit the disruption and to reduce installation costs, ground source heat pumps should be installed when the home is being built, or alongside building a house extension or carrying out a major home renovation.
Heat pumps deliver heat at a lower temperature than a boiler. So in winter expect to have the heating turned on for most of the time. If you live in an older property without modern insulation, ground source heating may not deliver the level of heating needed. Ground source heat pumps are not recommended for such properties.
What consents will I need?
The installation of a ground source heat pump is usually considered to be "permitted development", which means that planning permission is not required. However, if you live in a Listed Building or a Conservation Area it is recommended that you speak to your local Council before installing.
Ground source heat pumps will have to comply with the Building Regulations.
How much does a ground source heating system cost?
Expect to pay around around £10k to £15k for a typical system.
Subject to your property being suitable for a ground source heating system, expect a payback period of around 15 - 20 years.
Is there any grants or other funding support available?
The Green Deal scheme may be able to help you pay for the upfront costs of the installation through Green Deal financing. The installation costs will then be paid back over time, with interest, through your electricity bill.
Your ground source heat pump could earn you money under the Government's Renewable Heat Incentive scheme.
Where can I find further information?
For case studies and practical advice on siting ground source heating check out www.gshp.org.uk
- If you live in a draughty, older property we do not recommend installing a heat pump.
- If you have a mature, well tendered garden that you don't want to dig up we do not recommend installing a heat pump.
- If you already have a modern, gas fueled condensing boiler we do not recommend installing a heat pump.
- However, If you are planning a major renovation of you home, we do recommend that you consider installing a heat pump as part of an integrated heating system.