Reducin e nergy fo

Both satisfaction and frustration have accompanied our efforts to reduce our household’s energy footprint – the impact on the planet, including contribution to climate change, of our energy use for heating, lighting and appliances. We began our efforts in 1975 and, spurred on by the increasing problems facing our planet, have kept going. The financial cost has been quite high but we have saved by living simply and been lucky to have two small legacies to help out. Insulating your home is a good start and our first steps were installing rockwool cavity wall insulation and three inches of attic insulation. Now, belatedly keeping up with recommendations, we’re adding another five inches using Warmcel (made from recycled newspaper!). Ten inches is ideal but we use our loft for storage and with joists only four inches high raising insulation to eight inches involved much time-consuming DIY! We draught-proofed everything we could and in 2002 installed double-glazed windows with FSC wood frames from Green Building Store – we try to minimise the environmental impacts of the energy-saving products that we use. Another early achievement was to generate some energy we use sustainably and we’re delighted with our solar water heating panel installed in 1992. It has reliably produced hot water ever since – abundantly on sunny summer days and more frugally during bright

winter days. Solar operated pumps are available now but ours uses a little electricity. In 1999 we switched to a renewable electricity supplier to match our consumption with generation from sustainable sources. We are now with Good Energy. Switching suppliers is easy – for example over the Internet at www.greenelectricity.org. This website recommends Good Energy and Ecotricity as the ‘greenest’ suppliers in a market complicated by the Renewable Option and explains why some so-called ‘green’ suppliers are not really! Our renewable electricity costs more and anyway shouldn’t be wasted, so we use low energy light bulbs, replaced our worn-out fridge and washing machine with very energy efficient models and don’t possess a tumble dryer or freezer, the most energy-hungry appliances. We practise the energy-saving tips in Walk Cheerfully, Step Lightly but frustratingly having worked hard to save a few watt-minutes I do stupid things like forgetting to switch off my oven and waste a kilowatthour! People question whether small savings in energy are worth the bother, but little bits add up to significant amounts if enough people bother. Besides in the end the planet may be saved from tipping over the edge by preventing the emission of just one gram of carbon dioxide – remember the straw that broke the camel’s back! We aren’t on gas so had oil

central heating and decided this year to install an alternative system. The Green Building Bible lists carbon dioxide emissions for various heating sources. Wood is best (if sustainably sourced and efficiently burnt) and next come heat pumps – if correctly used. So we investigated woodfired boilers. Nowadays these are fairly automatic – pellet-fired boilers completely so – but big! Our preferred option, an Okofen wood pellet boiler with automatic pellet-feeding hopper, would have necessitated building an extension to house it. This would eat up our financial resources and could cause more greenhouse gas emissions than we subsequently saved. Frustratingly too late for us, Okofen have now introduced a prefab wooden shed to house the boiler and hopper. So we considered the most efficient heat pump. A ground source heat pump can give 4kW of output for each kW of electrical input. However we had a problem – our garden is too small! We couldn’t face destroying the entire garden to accommodate the two trenches, each one metre deep and forty metre long, for the pipes to extract heat from the ground. The alternative was a borehole 120 metres deep – but the machinery couldn’t access our garden and the cost was prohibitive. Frustrated again, we investigated air source heat pumps giving 3kW for each kW of input but cheaper

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the Friend , 5 January 2007 ng your ootprint Anne Brewer of Dorking Meeting writes from her experience at home

and easier to install being just a large box fixed to an outside wall. Microgeneration, who install HeatKing air source heat pumps, suggested additionally an extra solar panel and a Torrent Solar thermal store. This splendid new invention replaces both hot and cold water tanks, accepts input from solar panels, heat pumps and boilers, and supplies hot water for taps and radiators. So the solar contributes to central heating on bright winter days. The cost was around £13,000. We warranted a £2,400 Government grant but failed to get the application in and approved before work started – be warned! We took the plunge but had the thermal store equipped to accept input from a log burning stove with back boiler in case the system was inadequate during really cold weather. The system went live in October and is doing fine! The heat pump runs intermittently but makes a noise, which might annoy neighbours, but fortunately that side of our house overlooks

farmland. It doesn’t bother us indoors and won’t be needed in the summer, as the solar will supply all our hot water. The thermal store is cleverly designed, so hot water is unaffected by the central heating demands of a cold day and maximum use is made of input from the solar panels. Our thermal store is in the attic but could be sited in a garage or airing cupboard where your hot water cylinder used to be. Our airing cupboard was too small – usual problem! On recent dull days with no solar input the heat pump coped admirably producing hot water at 47°C and keeping the house comfortable at 15°C – we were already acclimatised to a low temperature! The pump only activated for about fifteen minutes an hour so could cope with a higher load, but it wouldn’t be suitable if you like a really warm house, as efficiency drops off with increasing differential between input and output temperature, which is why they are recommended for use with underfloor heating, which gives a warmer house at a

lower output temperature. It will work with outside temperatures down to -15°C. As we redecorated the kitchen using plant-based paints, we congratulated ourselves on our household’s nearly zero energy footprint. Even the old oil burner had gone, via Freecycle, to a restaurant owner planning to run it on used chip oil! Then something we read questioned the green credentials of heat pumps even if run on renewable electricity – such electricity is in short supply it said and should not be wasted on heating. Oh dear! An efficient log burner with a back boiler will reduce our dependence on electricity so that is our next project. What then? We could invest in a wind turbine or solar PV to generate our own electricity but you need an ideal site for the former to be effective and the latter is rather costly. I’ve a feeling that more effort to reduce our other areas of energy consumption is what the planet needs from us now – in my case more use of my bicycle!

Sources of information Anne found useful and suppliers mentioned: Centre for Alternative Technology Information Sheets. 01654 705989; www.cat.org.uk Energy Saving Trust: 0854 727 7200; www.est.org.uk Green Building Bible. Third edition. Published 2006 by Green Building Press. www.greenbuilding.co.uk Walk Cheerfully, Step Lightly. January 2006 edition. Published by Quaker Green Action. Ecotricity: www.ecotricity.com/thefriend; 0800 0326 100 quoting ‘The Friend magazine’ (see also back page) Good Energy: 0845 456 1640; www.good-energy.co.uk Green Building Store. Mail order supplies. 01484 854898; www.greenbuildingstore.co.uk Microgeneration: 0845 434 8084; www.microgeneration.com Okofen wood pellet boilers: the organic energy company, 0845 458 4076; www.organicenergy.co.uk

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