The heat is on

Lucy Denton investigates how heat pumps can help our heritage buildings in the move to a more sustainable future

THERE isn’t a building in the country that can’t be heated effectively with heat pumps,’ says Will McCarthy, senior consultant at ISO Energy in Horley, Surrey, ‘and it’s a myth that it can’t be done. It can be made to work, as long as it’s designed and installed correctly.’ The pressure is on to reduce carbon emissions and heat pumps have emerged as an energy-source antidote to the old fossil-fuel guzzling gas and oil boilers, endorsed by the Government offering grants of £5,000 or more to potential takers, as long as a new system meets certain standards. Yet, the response has been lacklustre, a curiously British phenomenon that means a significant lag behind other countries. ‘It will take time to catch up with the rest of Europe,’ adds Mr McCarthy.

Heat pumps have become a divisive subject, rousing bad press, notably for the hefty fees for purchase and installation, which often run into tens of thousands of pounds, and for the long wait for cost benefits. ‘What any good installer should do is produce calculations showing expenditure and payback time, but be aware that this could potentially extend beyond your lifetime,’ points out Ed Stancliffe, senior design engineer at ENG Design, based in London. The physical impact on the historic built environment can be invasive and the planning process protracted, depending on availability of conservation officers. Ground-source pumps require expensive bore holes or trenches to be dug by specialists, whereas air-source units can be noisy and unsightly. Both work best when combined with effective insulation, ‘which I would promote ahead of everything, where possible,’ says Mark Hoare, director at Hoare, Ridge & Morris architects in Suffolk, who has installed a ground-source heat pump at his own 16th-century timber-frame cottage and has ‘no regrets’.

There are more encouraging stories: at Grade I-listed Dorfold Hall in Cheshire, a superlative Jacobean brick-built house intended to accommodate a visit from James I, the tradition of shrewd development has been fulfilled in the 21st century. Here, one of the first heat-pump systems installed at a country domain, combining both groundand water-source energy from a nearby field and lake, has been nothing short of transformative in the effort to be sustainable,