Carleon House was built in 1861 and came into the Trust’s care in 1991. Since 1992 the house has provided accommodation for full-time volunteers carrying out conservation work in west Cornwall, particularly on the Lizard Peninsula.

© NTPL / Ian Shaw

Prior to restoration the house was in a very poor state of repair, with no insulation, draughty windows and doors, and the only source of heat was a log burning stove.

The challenge
Adopting sustainable construction techniques and renewable energy technologies was a key part of the project from inception. The aim was always to minimise the impact Carleon House has on the environment as a dwelling and through the materials selected in its renovation. Being an historic building, sensitively located, the scope for alteration of the external structure was limited. The house is of stone construction with slate roof and timber sash windows.

Insulation
Where windows have been replaced, locally crafted, FSC timber double-glazed units have been installed, where original sashes are retained these have been fitted with draught excluders. Additional sky lights have been installed in the kitchen to improve solar lighting. The roof and the walls that have been dry-lined have been insulated with Thermafleece sheep’s wool insulation. Using a natural insulation product such as Thermafleece also allows the building to breathe, so reducing the potential for condensation and damp problems.

Ventilation
A whole-house mechanical ventilation / extraction unit has been fitted in the loft space to maintain air circulation to prevent damp and to reclaim any available heat from the kitchen and bathroom. The log burning stove has been retained in the main living room but central heating has been installed using an underfloor heating system which is powered by a ground source heat pump, the heat collected from three 55m deep boreholes.

Water
Hot water is provided through a solar thermal hot water collector mounted on the roof. All pipes and tanks are insulated against heat loss and frost damage. Rainwater is also collected off the roof and directed to a 2,000 litre, underground tank and used for flushing the toilet.

Materials
All timber is FSC accredited, internal paints and finishes are from Biofa, and as far as possible have zero ODP and VOC content. All appliances are ‘A’ rated and refrigeration equipment is R600a hydrocarbon / insulation standard. All light fittings are low energy. All work was carried out by local contractors. Materials, fixtures and fittings were, where possible also locally sourced to ensure easy replacement and support the local economy.

Carleon House was recently awarded ‘Highly Commended’ in the 2007 National Energy Efficiency Awards Construction & Renovation category.