Water Source Heat Pumps in the UK: Costs, Pros and Cons

Water source heat pump (WSHP) is an extremely energy efficient (300%-600%) renewable energy based heating and cooling system. With the market demand for sustainable energy solutions on the rise, heat pumps are becoming an increasingly sought after heating solution for homeowners in the UK. 

This article will cover everything about WSHPs—how they work, their types, costs, and pros and cons, to help you decide if they are suitable for your home. 

But if you have already decided to get heat pumps for your house, you will need a reliable installer. To ensure you get the best value for your money it is recommended that you compare quotes from multiple installers. However, calling up different installers one by one will take up hours of your time. Fortunately, you can let WhatCost do the work for you. 

All you need to do is fill out our short 30-second form to get up to 4 free and non-obligatory quotes from vetted local installers. Click on the link below to get started!

Heat pumps work by making use of natural thermal energy present in nature—air, water and ground. Water source heat pumps (WSHPs) work by transferring thermal energy from an external source of water (river, stream, lake, well, borehole) into a house. 

The extracted thermal energy can be further heated using electricity for central and water heating purposes. For heat extraction, a water body with a surface area of 130m², 1.2 metres depth, and a pH level between 6.5 and 8.5 is ideal. The water body should be within 100 m of your house. 

While air source heat pumps (ASHPs) such as air to air heat pump, air to water heat pump, and ground source heat pumps (GSHPs) are more commonly installed, water source heat pumps are also a highly effective heating/cooling solution. This is because WSHPs are considered to be the most energy-efficient heat pumps because of the high thermal conductivity of water. 

WSHPs boast a coefficient of performance (COP) of 3 to 6 (sometimes higher), while ASHPs have a COP between 3 and 4, and GSHPs have a COP of 3-5. This means that for every unit of energy used by a WSHP, 3-6 units of heating/cooling are provided by the heat pump. Apart from the high energy efficiency, WSHPs are extremely durable, with an average lifespan of 20-25 years.

Water source heat pumps work on the thermodynamic principle of the refrigeration cycle. In simple terms, this means that a special fluid called a refrigerant is used to transfer thermal energy in a heat pump system.

The next thing to understand is that there are two types of water source heat pump systems—open-loop and closed-loop systems. You can find detailed explanation about the types of WSHPs in the following sections. 

WSHPs may sometimes have a boiler, but it is not necessary. Regardless of the type of system, the heat or thermal energy extracted from the water goes through the refrigeration cycle. 

To get a better understanding of how water source heat pumps work, read the following steps:

The two types of WSHPs are open-loop and closed-loop heat pumps. The difference between the two lies in how they interact with the original source of water and how they manage heat transfer. 

In an open-loop system, the heat pump extracts heat/thermal energy directly from the water drawn from the natural water source. After the heat extraction, the water is pumped back into the original water source. The overall efficiency of the open-loop system is higher, but it can fluctuate depending on the water quality and temperature. These systems require additional permissions for installation as they directly interact with the water body. 

In comparison, in a closed-loop system, an additional set of sealed pipes is placed in the water body, therefore the system never actually comes in contact with the water. These pipes have a mixture of water and antifreeze that absorb heat from the water and transfer it to the heat pump. Closed-loop systems are also more common as they are cheaper and easier to install. The maintenance requirements of closed-loop systems are lower than open-loop systems as these systems do not have direct contact with the water body. 

The estimated costs for water source heat pumps in the UK are between £6,000 to £11,000. The pipework laid in the water body could cost around £6,000-£15,000. The exact costs are not readily available as WSHPs are not commonly installed.  

However, the total costs can differ depending on the type of system installed, the heat pump size, the complexity of the installation, and the location. However, there are heat pump grants in the UK, including the Boiler Upgrade Scheme (BUS) that can be utilised for minimising the total costs by £7,500. 

Having said that, these numbers are just estimates, and we recommend that you contact a professional to get an accurate figure for your water source heat pump installation costs. Fortunately, you do not have to worry about finding a reputable installer on your own. 

Instead of wasting time searching countless websites and calling up numerous people, you could just fill out our 30-second form to get up to 4 free quotes from verified local installers. It is easy, quick and reliable. 

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The biggest advantage of WSHPs is their high energy efficiency (300%-600%), while their biggest drawback is the high installation costs. The following section will walk you through the pros and cons of water source heat pumps in the UK in detail. 

Advantages:

Disadvantages:

Water source heat pumps are a great alternative to fossil fuel based heating systems. They are highly energy efficient, rely on a renewable energy source and last for many years. With a 3-6 COP, you could be looking at significant energy savings over the years. 

That said, you should consider factors such as access to water sources and installation costs. While there are government grants available to subsidise the total costs, it is still a big investment. However, if you live near a water source and are ready to transition to a sustainable heating solution a WSHP can be ideal for your home. 

If you have made the decision to get a WSHP for your home you will need experienced installers who can do the complicated installation process with precision. Wondering where to find them? You can either waste hours of your time looking for reliable installers on your own or use our free and speedy service to get up to 4 non-obligatory quotes. 

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