Healthier homes on The Green

Anyone looking out from a building on The Green, a housing estate in Charlbury, at around 8am on two recent mornings would have had a reason to be puzzled. Why, they may have asked themselves, was a tall man with a ginger beard standing on the pavement looking at houses from various angles while monitoring the screen of a small portable device held at arms-length?

This seemingly odd behaviour had a useful purpose.

Sustainable Charlbury has launched its Greener Healthier Homes campaign and the first step is measuring heat loss from eight houses on The Green. The man doing strange things in the street, Douglas Drewniak, was recording thermal images which are later analysed to show where a house is leaking heat – whether through poor insulation, shoddy construction or simply gaps around windows or doors that let warm air escape. To build up a complete picture, he recorded several images inside as well as outside each house, using readily available equipment: a small portable CAT phone. These phones are used widely in outdoor industries and have much the same capabilities as other smartphones but the construction is more rugged. The thermal imaging software comes as a free app. Douglas works for Bioregional, a charity with an office in Oxford which provides expert advice to organisations and households on ways of sustainable living. This organisation has been commissioned by Sustainable Charlbury to do three tests on properties in The Green: heat loss, air-tightness and whether cavity wall insulation is working properly.

“We want people to know if they have got homes that are healthy and pleasant to live in – warm in winter and cool in summer. They will be amazed to discover how much warm air escapes and how much cold air comes in ….and then there is the advantage of lower energy bills”, explains Liz Reason, a Sustainable Charlbury volunteer. The Green was chosen for the tests because it is an area where many of the houses are similar. So lessons learned in one dwelling can, hopefully, be applied to improve energy efficiency and air quality in many others. Also, the estate went up in the 1970s, a period when building quality standards often fell short and nobody bothered much about insulation, which means retrofitting to higher standards could have a particularly worthwhile impact.

The tests are free of charge to households who have volunteered to take part in the survey. They will get the benefit of knowing where the weak spots are, areas in the house that most immediately need attention to stop draughts and air leakages. “Service penetrations are one of the major problems causing heat loss in many houses”, Liz explains, referring to leakages caused by careless drilling of holes that let heat escape as a result of plumbing in new washing machines or cables for TV aerials. For the longer term, the idea is to develop comprehensive “whole house plans” setting out the steps that might be taken over time to get maximum possible energy efficiency. Thermal imaging produces a kind of map of the house in which energy efficiency and heat loss is indicated by changes in colour. Areas with little heat loss show up as blue. Leaky windows and other places where insulation is lacking show up as red, yellow and white. An even blue across the whole image with few or no hot spots indicated by other colours indicates that the house is relatively energy efficient. Getting an accurate picture is quite tricky. Heat from sunlight and reflected heat from certain building materials can lead to a false picture of how much warmth is leaking out from within the building. Results are most accurate when there is a large temperature gap between inside and outside the house. For these reasons, thermal imaging is done early in the day.

The tests on The Green are part of something bigger. The eventual aim is to build up a picture of the energy efficiency of every house in Charlbury. Sustainable Charlbury is organising a public meeting to develop a plan to make the town zero carbon on 13th June to kick start the process of developing a plan to make the town zero carbon (details to be announced soon).

Charlbury already has its own solar farm, Southill Solar, that produces almost enough carbon emission-free electricity to cover the power needs of Charlbury, Finstock and Fawler. The next step towards a climate friendly future is reducing the amount of electricity the town consumes, which will require measures such as increased energy efficiency in businesses and homes. The Greener Healthier Homes campaign’s work in The Green is funded by a £5,000 grant from Low Carbon Hub, a community energy organisation based in Oxford, and a £1,000 grant from the Department of Business, Energy and Industrial Strategy.