Can I Get a Water Source Heat Pump (WSHP) on the Renewable Heat Incentive (RHI)?

What is the Renewable Heat Incentive?

The Renewable Heat Incentive (RHI) is a government run scheme designed to get more people investing in renewable energy.

Essentially, the scheme works by providing quarterly payments based on your rate of heat generation. The payments run for 7 years (longer for commercial properties) and, in some cases, the total amount paid back can be more than your initial expenditure for the installation. In this way, the Renewable Heat Incentive can actually be a pretty lucrative venture; it’s not only that you’re saving money on your heating, but you’re also getting paid to do it.

The biggest problem with the RHI scheme is that all of the technologies it promotes (biomass, solar thermal, heat pumps, CHP) are expensive to install to begin with. A water source heat pump won’t set you back as much as ground source, but it’s still in the region of £10,000+. So while it’s quite possible to make that money back over the 7 year payback period, it does require you to have thousands of pounds to invest in the first place.

Do bear in mind that payments are based on heat demand rather than metering.


What is a Water Source Heat Pump?

Heat pumps are remarkably smart little pieces of equipment. The core concept behind them is that small amounts of latent heat in the source (in this case the body of water) is extracted using a system of pipework, then compressed to concentrate the heat. The heat exchanger then transfers this collected warmth to be used in your home. Using this system, a water source heat pump situated even in a seemingly cold body of water can be used to generate real, usable heat.

Water source heat pumps are one of the most efficient types of heat pump, given that the heat transfer rate is significantly higher than with ground or air. Even better are water source heat pumps placed in moving water, since there is always new water hitting the pipework from which to extract the heat.


Can I Get a Water Source Heat Pump on the Renewable Heat Incentive?

The Renewable Heat Incentive legislation is a not very well explained on this subject, and has created quite a bit of confusion among people wanting to install water source heat pumps. The list of eligible installations goes in to painful detail over what is allowed and what isn’t, but never mentions water source heat pump. It’s only in the footnotes that you’ll find this little nugget:

“ground source heat pump” means—

(a) in the case of a shared ground loop system, the piece of equipment installed in each premises which generates heat in those premises using the heat energy provided by the ground loop;

(b) in all other cases, a plant which generates heat by absorbing energy stored in the form of heat in the ground, including water in the ground, or in surface water, but does not include a plant which is a deep geothermal plant;

This is why people are confused about whether water source heat pumps fall under the remit of the scheme or not. Water source heat pumps do qualify for the renewable heat incentive, but they are classified as ground source heat pumps.

This means that any water source heat pump installation (providing it follows the rest of the ground source heat pump criteria) is eligible for the same payments as ground source. This is updated every few months, but as of September 2018 that was 20.46p / kWh – you can use our guide to calculating heat pump renewable heat incentive payments to figure out exactly what this would mean for you.



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