C O N T E X T 1 4 9 : M A Y 2 0 1 7 29 cost-effective measures will not only reduce energy use, they will also reduce the size of the replacement system required, saving money, space and hassle. Questions of appropriateness should include: Is it comfort heating or conservation heating that is required? Is hot water needed for sinks and other areas? How big are the current radiators and pipework? Is there sufficient storage space for woodchips or pellets? Are there suitable delivery routes and access? Is there sufficient electrical supply and capacity? Is here adequate capacity and enough people resources?What is the budget? At Plas Newydd, a country house on the north bank of the Menai Strait in Anglesey, we spent £4,500 on insulation, £1,500 on servicing boilers, and £15,000 on secondary glazing and window improvements. Overall, a spend of £21,000 has led to energy saving of 20 per cent and an annual saving of £37,000 in running costs. Following on from this work we completed the installation of the UK’s first marine water-source heat-pump system.This led to a reduction of £40,000 in heating costs. At Beudy Gwyn Cottage in Snowdonia, northWales, as at Plas Newydd, we first undertook a heat-loss assessment and surveys. Measures included new LED lighting, loft insulation, thin-profile colour-matched secondary glazing, draught exclusion and pipelagging. The property had an ageing, inefficient oil-fired boiler heating system. Considerations about its replacement included its location at the end of a farm track (we have had difficulty delivering in the past in winter); aesthetically and environmentally we wished to remove oil storage and ugly tanks, and avoid the risk of oil spills during delivery; the building had thick walls and good thermal-mass potential; but the radiators were too small and too few to cater for lower circulating temperatures of heat pumps. We concluded that deliveries and storage of fuel (whether oil, LPG or woodchip) was aesthetically and practically difficult, so we selected a 17kw ground-source heat-pump system. The cottage needed a new radiator system, so this was sized to take the lower temperatures of a heat pump. A first for the National Trust was the installation of the heat collector in the nearby field: a mole-ploughed collector 600mm deep and at just under 700m long was installed in two days.This dramatically reduced the installation cost (mole ploughing is roughly half the price of a buried coil, which is roughly half the price of a borehole system).The heat pump unit, the size of a fridge freezer, was integrated into the utility room. It does not take up much more space than a wall-mounted LPG or oil boiler. The project cost approximately £12,000.We will be monitoring operational performance over the year. Earlier in the year I decided that it was about time I got my act together to provide a better heating solution for my own home than simply open fires and buying the family jumpers. I had previously looked at air-source heat pumps as the cottage dates back to 1700s and has metre-thick stone walls, so has good thermal mass, but I wanted to reduce my electricity bills and keep the character of our cottage at the same time. I had already increased insulation, installed double glazing, made the doors fit, and changed the lighting to LED. We decided on a simple solution: a log boiler stove to distribute heat to new radiators throughout the house, and to provide sufficient hot water for me to wallow in a bath.The cost was comparable to that of fitting an oil/LPG boiler (£1,500), as whatever the heat source I needed radiators anyway.The annual running costs are £500: a three-year payback. Whatever the size or age of property, the guiding principle has been one of appropriateness, whether in aesthetics, technical viability or, most important, practicality. Start by understanding the use of a building and what is wanted from it; carry out a proper heat-loss assessment to ensure the required output. On practicalities, ask who loads it, manages it and delivers to it. Only then, and with a good understanding and a good brief, should we look at the technological options and engage with external specialists. Paul Southall is environmental advisor at the National Trust and co-founder of the Fit for the Future Environmental Network. At the author’s own home, installing a log boiler stove was rewarded by a three-year payback. At Beudy Gwyn Cottage in Snowdonia, northWales (far left), a ground-source heat-pump system was installed. A 3-D sun-shading model of the front of Plas Newydd
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