Building type Domestic
Building age 1800-1914
Location Higham
Cost of work £16,500
District Forest Heath
Features Groundsource Heat Pump,Insulation and Glazing

The house comprises  a pair of nineteenth century farm workers cottages considerably extended at the rear sitting in a mature garden of one third of an acre, all within the Higham Conservation Area . The challenge was to make it as energy efficient as possible.

Sustainability Features


The first step was to bring the insulation up to near the maximum attainable for the mixed construction methods used in the different parts of the house. Firstly the house with its three separate roof spaces was insulated up to current Building Regulations Standards when the main roof was refurbished in 2008. The solid concrete floor was fitted with under the carpet reflective material.


A variety of different types of double glazing, sealed and secondary, had been used in the different parts of the house.


With insulation up to standard the project was to replace the aging oil fired boiler with a modern energy efficient one. A ground source heat pump was the preferred route forward. The existing system of radiators was redeployed with the heat pump in lieu of the former oil fired boiler.

Ground Source Heat pump

We used a Greenline (IVT ) 8.8 kW heat pump with an integral hot water tank and back up 9kW electric cassette heater . It was supplied by Ice Energy Ltd who designed the whole system . Cost £6900 with VAT.

Groundworks . Costs vary according to the method selected and we chose the most expensive option , to protect the garden . The two 60m boreholes and all the internal plumbing works cost £9600 with VAT . Total cost of the project £16500

Performance . This winter has been an exceptionally long and cold one yet the system performed faultlessly maintaining the temperature that we selected continuously with very little use of the electric cassette.


Design Process

The owner, a former professional town planner took care of this aspect of the changes himself.  He has long been aware of the use of far more efficient technologies in Scandinavia , where he has personal friends and contacts , and so  achieving a green solution has long been a cherished objective.



The scheme was eligible for a £1500 grant.


Green Lifestyle

Heat pumps are expensive to install and involve some disruption to the grounds of a property; however the owners motivation for deciding to incur the significant capital cost and the short tern inconvenience was a mixture of economic and environmental factors. In short it was considered that this heating system was the right answer financially, for the long term, and from the environmental point of view



At the time of writing we are at mid winter and the 24 hour a day warmth , delivered at low cost , making few demands on our shared environment is proving very attractive and successful indeed. The heat pump is an easy technology to live with and all the research and organisation seems well worthwhile. The machine is best suited to someone who is unafraid of using simple science and technology as it does require some, although very simple maintenance and supervision.


Suppliers and Professional Services Used

Equipment and initial advice from Ice Energy of Eynsham, near Oxford. Installation by ALF Properties, specialists in this technology.



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