English Rural Housing Association


E.ON and English Rural Housing Association help tenants to lower energy bills by up to £4501 and reduce carbon emissions by up to one and a half2 tonnes per year

English Rural Housing Association (English Rural) is a registered social landlord, established to provide affordable homes in small villages for local people. In December 2008 English Rural approached our Sustainable Energy team to identify sustainable energy solutions for four new build sites:

  • Stone in Oxney (six homes)
  • Dunsfold in Surrey (11 homes)
  • Rolvenden in Kent (12 homes)
  • Smarden in Kent (12 homes)

English Rural wanted a single low carbon energy solution that supplied both heating and hot water whilst also achieving an Eco-homes rating of ‘very good’.

By working with E.ON Sustainable Energy English Rural were able to apply for grants, under the LCBP P2 programme, contributing over £170,000 towards the cost of the project.

The solution

After considering the energy requirements of the new homes our design team specified individual HeatPlant units for the development due to their low maintenance requirements and whole life costs. The flexibility to locate the units internally or externally also made them an ideal option.

HeatPlant is an advanced and robust technology which offers lower running costs for tenants, versus traditional oil and electric heating systems, helping to alleviate fuel poverty, and reduce carbon emissions.

The installation of the 41 HeatPlants will reduce energy bills by £84003 and save over 353 tonnes of carbon each year across the four sites.

These are the first English Rural properties to benefit from Ground Source Heat Pump (GSHP) technology to provide the central heating and hot water requirements. The properties vary in size, with annual heating loads between four and nine megawatt hours. The HeatPlant units are connected to a wet radiator system, providing space heating and domestic hot water cylinders to provide hot water.

In some of the English Rural properties the HeatPlant units were fitted externally, in a specially designed cedar wood enclosure, freeing up valuable internal space.

The tenants have a conventional wall mounted time switch and room thermostat together with thermostatic radiator valves to give them total control over their heating and hot water requirements. Many have come from electrically storage heated homes which could be inherently difficult to control and costly to operate.

The installation of the HeatPlant units, including drilling the boreholes for each home, was managed by the E.ON Sustainable Energy team, making the process for English Rural simpler and easier as they had one point of contact for the whole installation. Our team also visited tenants to explain how to use their new heating system.

The Technology

  • 41 HeatPlant units with domestic hot water cylinders
  • HeatPlant works in all seasons, providing the right level of space heating and hot water
  • Designed specifically for the UK domestic market and manufactured in the UK

How HeatPlant works?

HeatPlant extracts solar energy naturally stored in the ground from a borehole and increases its temperature to the right level for space heating and hot water. They are powered by electricity but can provide between three and five times as much energy as they consume. Heat is extracted by cooling a fluid mixture of water and antifreeze, which is pumped around a closed circuit ground-heat exchanger.

The Benefits

  • Delivers 100% of heating and hot water requirements so no need for an immersion top up as output temperature is 60˚C for domestic hot water
  • No separate buffer vessel required
  • Self-contained unit designed to fit under kitchen work surfaces or can be fitted externally in a housing unit
  • The lowest running cost system for ‘off gas’ network areas
  • Helps alleviate fuel poverty by reducing energy costs for tenants whilst providing reliable heating and hot water all year round
  • Lowers CO2 emissions versus traditional oil and electric heating systems
  • No need for gas safety certificates as with a traditional boiler or annual servicing
  • Proven technology with a long life expectancy of up to 25 years for the HeatPlant and 50 years for the ground loop
  • Can assist in achieving Code for Sustainable Homes targets


1. Cost savings are based on an annual heat load of 7,832kWh/year, GSHP Co-efficient of Performance (COP) of 2.4, and a fuel cost of 0.1132 £/kWh.
2. Carbon savings are based on an annual heat load of 7,832kWh/year, GSHP COP of 2.4 and an emissions factor of 0.422kg/CO2.
3. Carbon and cost savings based on the annual heating requirements of each property, as specified by the E.ON Sustainable Energy Design team, a COP of 80% for gas boilers and 3.2 for the GSHP. This figure is adjusted to 2.4 as per SAP 2005 as the sites use radiators. Emissions factors of 0.194kg CO2/kWh for mains gas and 0.422 kg CO2/kWh for electricity and a fuel cost of 0.0292 £/kWh for mains gas and 0.1139 £/kWh for electricity and a radiator design flow temperature of 50˚C.