Case Study

Rural Home retrofit from Electric Boiler to GSHP

Mr H, lives in a large rural home off the gas grid in Norfolk, this Rectory House is a long term family home, which has been passed down through generations. 

The property previously had a ground source heat pump installed in 2010. Unfortunately the company who installed the original heat pump are no longer in business and since the installation, the customer had experienced numerous problems and breakdowns.  The ground source heat pump did not work properly, this had mainly been down to the poorly fitted ground loops.

Unfortunately, he hadn’t experienced a heat pump system which could supply consistent heat and he was very disillusioned with a ground source heat pump as a method to heat his home.

When the heat pump stopped working, he hired another installation firm who then recommended and installed a commercial sized 38kW Electric Boiler, with rising electricity prices, the customer was spending £25,000 a year on electricity for his heating.

The customer did not feel this was an affordable situation to continue and therefore contacted R A Brown Heating Services, to see what alternative options we could suggest.

When the solution was specified, the total heat requirement for space heating and hot water combined was 92,942 kWh/yr.  Borehole Drilling Rig

As the customer already had 3 Phase electricity, this supported our recommendation of a 40kW NIBE F1345 GSHP. We reused the customer’s existing radiators.

3 x 136 metre boreholes were calculated to be needed for the ground source heat pump.

The plant room was fitted in the cellar of the property, which housed the heat pump, buffer and hot water cylinder.

The customer’s main objective was to reduce running costs and carbon output from his home. A ground source heat pump was the solution which produced the least amount of carbon.

Electric Boiler v’s GSHP CO2 Emissions

The estimated annual CO2 emissions for his existing electric boiler system was 12,640.11 kg CO2/kWh per year.

The estimated annual CO2 emissions for the newly installed GSHP is 3452.36 kg CO2/kWh per year.

CO2 savings to be made with our recommended solution:

By installing the GSHP system there is a saving of 9187.75 kg CO2/kWh per year.

As the property is in an off gas grid area, if the customer had considered an oil boiler, this would have produced an estimated annual CO2 emissions of 27,696.71 kg CO2/kWh per year. Plant Room

By choosing to install the GSHP system rather than the oil boiler, there is a carbon saving of 24,244.35 kg CO2/kWh and 9187.75 kg CO2/kWh compared to his existing electric boiler.

This installation is a 40kW Ground Source Heat Pump, with 3 phase electricity and 3 x 136 metre boreholes.

The opportunity to change a heating system usually only comes round every 15 years or so, unfortunately for this customer due to his previous experience of a ground source heat pump, he made the decision to move away from renewables, in favour of an electric boiler.

This customer regretted his decision to switch to an electric boiler as this has cost him a great deal in installation and running costs. However, as the electric boiler is still so new it has been set as a back up should the customer ever require it.

The electric boiler, was producing 12,640.11 kg CO2/kWh per year. Over 15 year period the electric boiler would produce 189,601.80 kg CO2/kWh per year. With the new ground source heat pump installed this means there is a saving of 9187.75 kg CO2/kWh per year over the same 15 year comparison period this is a carbon saving of 137,816.25 kg CO2/kWh because a ground source heat pump was chosen.

Find out more about ground source heat pumps.


We are very happy with the work R A Brown completed, they are very knowledgeable and experts in heat pumps.

Mr H, R A Brown GSHP Customer

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