Knowlands Farm Granary

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Knowlands Farm Granary

Address: Knowlands Farm Granary, Spithurst Rd, Barcombe BN8 5EF
Owners: Nick and Harriet Lear
Type: Barn conversion
Built: 2002
Beds: 3
Walls: Timber frame
Residents: 2 adults


Water source heat pump
Underfloor heating
Double glazing
Underfloor insulation
Solar PV (10 kWp)


Nick and Harriet have lived at Knowlands Farm for more than 40 years and downsized to the barn conversion from the main farm house in 2002.

This conversion was carried out to 2002 standards, so included solid wall insulation, insulation between the rafters, double glazing and even underfloor insulation with underfloor heating. However, although the farmhouse had a biomass boiler, the Granary conversion has had oil fired central heating and an oil fired Aga right up until 2013. This has now changed, with the installation of a water source heat pump, extracting heat from the lake to provide space heating and hot water. At the same time, the AGA has been converted to electricity, to exploit the extensive Solar PV installation on the adjacent barn.

The couple have long pursued a sustainable lifestyle, having retained 10 acres of farmland up until 15 years ago, which they used to keep a couple of jersey cows, three or four sheep and some pigs, to try and meet all their family’s food needs. They sadly stopped at that time, due to increasing bureaucracy, which was hard to cope with for such a small operation. However, Nick has continued to carefully husband the 70 acre wood as a nature reserve, particularly for the wide range of local butterfly species. He also harvests timber and firewood, which they sell.

Energy efficiency measures

Heating and hot water

In 2013, a water sourced heat pump was fitted by local specialists, A Greener Alternative. This takes water from the lake and pumps it underground to the house, where the heat is extracted by a heat pump. As the house already has underfloor heating in two areas, it is ideally suited to the lower temperature constant output of this equipment. Existing radiators in the bedrooms and kitchen have been retained for the time being, but some may need upsizing to compensate for the cooler circuit temperature.

An air source heat pump was also considered, but it was felt that the lake was too good a resource to waste and would prove cheaper and more productive in the long term.


The barn conversion was done in 2002 under high building regulations insulation standards, which are not far different from current. The existing timber frame was insulated with solid foam insulation between the studs and rafters, with solid insulation beneath the new solid floors, some of which have underfloor heating.

Windows are double glazed to a U value of 2.2 or better.

Renewables and Low carbon technology

In March 2002, the couple decided to place a substantial, 10 kWp PV installation on the small barn nearby. This was undertaken by Esola of Crawley, the only firm approached who were able to fit panels on the existing corrugated asbestos roof.

This is producing around 12,000 kWh of electricity each year, creating an excellent revenue from the Feed in Tariff and also neatly offsetting the electrical load from the heat pump and Aga.

The water source heat pump also displaces the former heavy carbon emissions from the oil fired system, whilst having much lower running costs. Installation costs are being offset by the new Renewable Heat Incentive, which subsidises the heat generated.

Other sustainable Measures

Nick manages the 70 acres of woodland, with a particular interest in the thirty two different butterfly species found there.

Natural Materials

Much of the furniture in the house was made using oak sourced from the woodland, which also provides logs which are sold to the public.

Water conservation

Harriet takes water conservation seriously and saves the cool water which is normally wasted when waiting for taps to run hot, which she store in plastic containers and uses to water her vegetable garden.


Whilst the PV and Heat pump will reduce CO2 emissions by a massive 7 tonnes per annum, the AGA still represents a very heavy user of energy. Hopefully the conversion to electricity will allow greater control, but there really is no way of making a traditional AGA truly energy efficient.



Builder: Simon Suter: 01435 86698301435 866983
Water source heat pump: A Greener Alternative, Sheffield Park:
Solar PV: Esola, Crawley.


Knowlands Farm Granary
Knowlands Farm Granary
Knowlands Farm Granary
Knowlands Farm Granary
Knowlands Farm Granary