Thermal images of North Oxford

Last winter LCON borrowed a thermal camera which belongs to the County Council,  and up to 20 willing guinea pigs invited LCON committee members in to look for their cold spots indoors and the hot spots outside. The camera turns whatever it sees into a palette of colours depending on the heat emitted by the surfaces.

Every home was different, but in every one there were opportunities to reduce our inadvertent carbon footprints. And what did these intrepid photographers find?

One of the most dramatic examples seen was the impact of the solid walls we have in the area. One home had lined their walls inside with insulating material on battens to create a warm inner surface; while others complained of rooms which had lengthy runs of cold external wall punctuated by windows. This is possibly the most difficult problem to tackle: external insulation is best (and most expensive), dry lining a good alternative if space and budget allows; and cheap and cheerful is lining with Sempatap. (See below for links about this.)

Another lesson learned was the impact of floors, especially where the floor is suspended. One homeowner has decided to properly insulate their basement ceiling as work is about to be done;  another is covering their leaky timber floor with a cork layer. Both will increase comfort and reduce heat losses.

Visiting on cold evenings always shows up even the best double glazed windows as blue – or at least with blue tinges where the draught leaks in and cools the frame. The standard to match is moving not to double glazing now but to triple glazing. But this is still expensive, as is replacing any window, especially if it’s an intricate sash design. What the camera revealed was how much can be done with window coverings. The best example seen was a house where the windows were covered both with blinds and then curtains on top: very little heat escaped leaving the rooms nice and cosy.

The joys of having open fires are always balanced by the impact of open chimneys. Open fires, wonderful as they are, are very expensive both of fuel when they are alight but of heat when they are not. Images outside houses with open chimneys show a white gash of heat in an otherwise cold wall: chimney balloons and chimney sheep are a simple way to block the flue temporarily.

Front doors, even when closed, show how leaky they can be. The best houses have an outer door to create an airlock effect and this makes a dramatic difference. If that cannot be achieved, then the old fashioned method of deploying a curtain across the aperture works well. This can be complemented by a “portiere” which lifts the curtain a little as the door opens allowing it to fall all the way to the floor. And if a curtain is a little clumsy all year, remove it for the summer.

The final use of the camera found hotspots indoors, rather than the expected cold spots. Bright white pinpricks of heat were caused by small halogen lights (the bulbs often burning at 80) where an LED would produce virtually no heat. Most of these bulbs are simply replaceable but make sure you install the correct voltage. And finally electrical equipment is a sure source of heating: printer transformers, phone plugs and other electrical equipment which we tend to leave on all the time. Some of these devices produce heat even when switched off. Small wireless switches can easily be purchased which turn off  sets of equipment when you leave the room without having to grovel around the plugs each time.


1 Sempatap comes on a roll and is DIY doable: see

2 Triple glazing: examples at

3 Chimney sheep and chimney balloons at and

4 Portiere rods from

5 Wireless switches from and look for Bye Bye standby.

6 LED lights from any good website including

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