Project Summary: How Water Source heat pumps extract heat from a nearby water source which can be used to heat your hot water and your home.
Water source heat pumps work in essentially the same way as ground source heat pumps. The system transfers heat from a nearby water source such as a lake or river to your home through a heat exchanger attached to your house.
A ground loop is a length of piping that is used to collect heat from the ground or the water source and take it to the heat pump. In a water source heat pump system the ground loop can be arranged in two different ways:
Installing this system will lower the cost of heating your home, although as this is still not a very commonly installed system the savings that are achievable can vary. With the Renewable Heat Incentive subsidies there are also government-backed incentives which will increase your savings.
The Renewable Heat Premium Payments scheme allows you to claim a voucher for £1,250 towards the cost of installing a water source heat pump if your existing heating system uses oil, solid fuel or electricity, and from summer 2013 onwards the government plans to offer homeowners regular payments to generate renewable heat through the Renewable Heat Incentive scheme.
There is also a loan available for the cost of installation through the Green Deal scheme. The loan is repaid through payments on your energy bills, and as the payment shouldn't exceed the saving you've made this should mean that you pay no extra money to have a renewable technology in your home.
You will need to have a large water source, such as a river or lake located near to your house. Installation may be expensive as you might need to hire divers or drain the water from the lake.
Your home's size and your requirement for heat will determine the length of the loop - longer loops are capable of extracting more heat from the water, but require a greater area of water.
There are different heat pump systems available and they work on a similar principle but instead take up heat from different sources:
If you are planning on installing a Water Source heat pump it is essential to get the correct planning and environmental permissions in place as you will be using a local water body. The Environment Agency will be able to assist you with this.
In order to be eligible for the Renewable Heat Incentive subsidies the system must be fitted by a MCS accredited installer.
You will need to think about the following:
Coefficient of Performance (CoP) describes a heat pump's efficiency; it is the ratio of heat output to energy input and the larger the value the better. Heat pumps can generate up to 4 kilowatts of energy for each kilowatt of electricity they use. This means that heat pump systems can be very energy efficient. Another measure known as the System Efficiency Ratio (SER) describes the ratio of how many units of electricity the entire heating system uses to the number of units of heat the pump produces. Both the CoP and SER values range from 1 to around 4 - when choosing a system look for one with a value as high as possible.
The installation time for a water source heat pump system varies with the size of the system being installed. By combining the water source heat pump installation with other building work you can potentially save money on your installation. This is particularly true if any changes to your heat distribution system are needed, such as fitting under floor heating.
You should always use an MCS accredited installer to install your heat pump system as this will allow the installation to qualify for the appropriate grants and subsidies. MCS accredited installers have the qualifications necessary to be able to sign off installations that comply with the government's Renewable Heat Incentive scheme. If you are getting the system installed through the Green Deal you will need a Green Deal installer to carry out the work.
After the initial installation cost, how much the system costs to run depends on a number of considerations - including the size of your home and how well insulated it is. If you choose an open-loop water source system the maintenance cost is normally higher, but this system is also likely to be more efficient.
As well as the savings you will make on your heating bills you could be eligible for a voucher for installation costs worth £1,250 from the Renewable Heat Premium Payments scheme as well as potentially being paid for the heat yours system generates through the Renewable Heat Incentive, due to be introduced in 2013. For more information on the Renewable Heat subsidies visit our RHI page.
Thanks to the recent launch of the Green Deal Scheme you could also qualify for financing worth part or all of your installation costs. The scheme pays for the installation on your behalf and then takes this money back through your energy bill using money you have saved by using the technology. This should mean that the installation does not represent any extra expense for you; though there is interest included in the payments which means that overall you will save more money by paying for the installation yourself. For further guidance on the Green Deal scheme take a look at our Green Deal page.
Heat pump systems need to use some electricity to pump the ground loop fluid around the system. However, the amount of thermal energy that they take up from the water source is higher than the amount of energy that is used to run them, meaning that they are energy efficient systems.
Heat pumps work in a different way to conventional boiler systems in that they generate lower temperature heat over much longer periods. This means that ideally you should leave the system running constantly during the winter to maximise efficiency. It's also best to install Low Surface Temperature (LST) radiators in place of your normal radiators for use with the pump. Their larger surface area makes up for the fact that the heat pump produces hot water at a lower temperature.
The exact amount of money you will save will vary depending on your current heating system. You can also get a voucher for £1,250 (the Renewable Heat Premium Payment) and quarterly payments for the heat you generate (Renewable Heat Incentive) if the pump is installed by an MCS accredited installer. Heat pump systems also come with some additional benefits:
The energy and money you save by installing the pump will depend on several things:
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