Could ground source heat pumps replace gas boilers? To address the challenge of reaching zero carbon targets, the government is providing grants to encourage property owners in England and Wales (whether this is a home or a small non-domestic property) to install low carbon heating systems such as heat pumps, through the Boiler Upgrade Scheme.

These £6,000 grants can help property owners manage the upfront cost of low carbon heating technologies when they come to replace their traditional oil and gas boilers.

The Energy Saving Trust says a ground source heat pump, sometimes referred to as a ground-to-water heat pump, transfers heat from the ground outside your property to heat your radiators [read our article on air source heat pumps here].

Thermal transfer fluid – a combination of water and antifreeze, also known as ‘brine’ – travels around a loop of pipe, buried in your outdoor space.

• This loop could either be a long or coiled pipe buried in trenches.
• Or a long loop (called a ‘probe’) inserted into a borehole with a diameter of around 180mm.

Heat from the ground is absorbed into the fluid, which then passes through a heat exchanger into the heat pump. This raises the temperature of the fluid and then transfers that heat to water.

According to the Ground Source Heat Pump Association – the trade body working on the transition to low carbon energy systems – for every unit of electricity used by the heat pump, three to four units of heat are captured and transferred.

So a ground source heat pump that has been installed correctly can be 300% to 400% efficient in terms of its use of electricity. Operating at this level of efficiency means there will be 70% lower carbon dioxide emissions than for a gas boiler heating system.

It’s also worth noting that if the electricity comes from a renewable energy source, then carbon emissions can be reduced to zero.

• potentially lower fuel bills
• reduced carbon emissions, especially if combined with another renewable energy source such as solar panels or a wind turbine
• can heat your property and hot water
• can be reversed in summer to provide cooling

The Department for Business, Energy & Industrial Strategy says heat pumps are cleaner and cheaper than fossil fuel boilers.

According to GSHPA, heat pumps save carbon emissions. Unlike burning oil, gas, LPG or biomass, a heat pump produces no carbon emissions on site (and no carbon emissions at all, if a renewable source of electricity is used to power them).

The International Energy Agency, in its most recent report, suggests no new gas boilers should be sold after 2025 if net zero targets are to be met by 2050.

The Energy Saving Trust says the cost of installation varies and can be influenced by:

• Access to the ground and whether you choose trenches or a borehole to lay the ground loop.
• The brand, model, and size of heat pump.
• The size of the property and how much heat it needs.
• Whether it’s a newbuild or an existing property.
• Typical costs are around £24,000 if your ground loop is buried in trenches and could be around £49,000 if a borehole is needed.

The specialists recommend speaking to at least three installers to provide a quote for your heat pump system to give you the best idea of likely costs.

Tax benefits

You can receive a discount on CCL (Climate Change Levy) taxes paid to your energy supplier by signing a Climate Change Agreement (CCA).

This is a voluntary agreement with the Environment Agency to reduce energy use and carbon emissions. Find out who is eligible and how to apply.

You can find out if you are eligible and how to apply here.