A Guide to Ground Source Heating
Everyone needs to heat their home and with the cost of fuel rising, many homeowners are looking for improved methods of heating. Ground source heating is a type of system that uses the natural heat below the surface of the ground to provide heat for a home. This heat is extracted from the ground using pipes that are buried outside in the garden. The pipes will not freeze even when the temperature drops as they are filled with antifreeze and water; this mixture absorbs the heat from the ground and sends it through a heat exchanger and on to a pump which is connected to your indoor heating system.
The size of the loop that you will need in your garden will depend on the size of your home – i.e. the bigger the property, the bigger the loop. With this in mind you need to ensure that your garden is the right size for the ground loop to be buried. In some cases where space outside is at a premium it is possible to use Boreholes. They are dependent on locating a permanent and reliable source of ground water at a reasonable depth. Boreholes are costly and good access is required for the equipment. You will need a survey to determine the best option.
A typical 5 bedroom house that is well insulated may require 6 boreholes @ approx. £125.00 per meter drilled (Cost @ 2013). It can work out very expensive
Some of the major companies who manufacture Ground source pumps will provide a survey. From this survey they will recommend the type of installation & equipment best suited.
How Does Ground Source Heating Work?
As mentioned the liquid in ground loop will absorb heat from the ground and pass this through a compressor & heat exchanger this compression will make the temperature of the rise. Don’t worry about the heat underground being lower during the winter as there is very little difference in the underground temperature at different times of the year. Absolute zero i.e.: in outer space the temp is -280deg so anything above has heat.
The fluid inside the pipes that has been heated up will then pass into your home via the under –floor pipe system. The fluid then returns back to the ground loop to start the process again.
Is Ground Source Heating Right for You?
Before you decide to have ground source heating installed you should think about the following points:
- What kind of heating system do you want to run from it? If you are thinking along the lines of traditional radiators you could find that ground source heating is not suitable. This is due to the fact that radiators need to have a high temperature to work properly and ground source heating can’t always achieve these temperatures. In most cases ground source heating is better suited to low temperature under-floor heating systems
- Is your garden big enough to have the external pipe work installed. Or do you have a permanent source of ground water located at a reasonable depth.
- How well is your home insulated? – Before starting the process. Get a SAP report this will determine the heat loss from your property- from this report you may need to upgrade the roof or wall insulation, change the windows. It’s important to remember the less heat escaping through the fabric of your home the less heat the system will need to produce.§ Any reputable company will require a SAP report before they are able to design a system.
Obviously undertaking a project like this will mean calling in experts, you should not attempt this without being fully trained. There is a huge amount of technical knowhow involved with regards to the best system that suits your property. The depth the ground loop should be buried and the distance apart that loops need to be are critical to how well your system will perform. In most cases you will not need any form of planning permission for ground source heating, however it pays to double check this with the local authority in your area, as in some places permission may be required.
Benefits of Ground Source Heating
- Cheaper running costs- Remember the installation cost will be high in comparison to a traditional boiler & radiator system
- There are no ventilation requirements that you will need to consider, unlike many other types of heating system
- Ground source heating is very reliable, this is due to a system not being made up of many parts that move and therefore break down. As the ground loop is buried it is not exposed to the elements as it is protected underground
- You will be able to save money, in many cases, when compared with your existing heating system
- You could qualify for payments from the Government under their Renewable Heat Incentive
- Depending on the fuel that you have previously used to heat your home you could be reducing your home’s carbon emissions
- The maintenance involved with ground source heating is very low, which is why this type of technology is called ‘fit and forget’
- If you have used oil or any other deliverable fuel you will be able to wave goodbye to these deliveries
- Installation costs are high
- You will need to have under floor heating installed inside the property. This is costly and will mean total disruption of the home
- Ground source is better suited to new builds because of the costs mentioned above
- You garden assuming its big enough will need to be excavated to a depth of approx. 1.2m for the external pipe work. A typical 5 bed house that’s well insulated will require 300m of pipework to be buried
My tip – If your home is currently conventionally heated. You have a system that works and you’re happy. You don’t have a desire to part with a huge amount of money. Leave well alone, as you will never recover the installation cost. If you are planning a total refurbishment or building new then it’s worth taking a serious look.
Maintaining Your System
Maintenance for ground source heating is very straightforward and the majority of systems will come with a ten year warranty and most should last for twenty years or more. Once installed you should check the system yourself each year and then every three to five years you should get it checked by a professional.
At the time when your system is installed you should be left with a list of points to check so that you can undertake this yourself and you should not have a system installed until you have discussed its maintenance needs to ensure you can keep up with them.
The Ground Source Heat Association states that maintenance of these systems is low and in addition to this there are no safety checks that have to be undertaken once the ground loop has been buried correctly.
Most ground source heating systems for homes up to 6 bedrooms will cost from £9,000 to £20,000 to be fully installed and this cost will depend on the size of your home. While this might seem like quite a lot, the savings that can be made are very impressive, particularly when compared with the cost of fuel bills right now.
You will start to save money from the time that your new heating is up and running. As the system uses electricity it will not be free to run, but as you will be replacing another fuel it will cost less. For example, if you are replacing electric heating with ground source you can save up to £610 per year based on a three bedroom home.
In the summer of 2013 the Government is launching the Renewable Heat Incentive (RHI) which you can join and earn money, if you generate more heat than you can use. So if you are having ground source heating installed this is something that is worth looking into.
Image credits: xJason.Rogersx