Thermal images reveal how poorly insulated homes in London are causing people to spend more on energy bills

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Ella Wills6 February 2019

These thermal images show how poorly insulated old homes may be forcing Londoners to spend more on their energy bills.

The infrared stills show heat escaping from homes across the capital during the winter cold snap.

Heat is seen leaking through gaps in windows, doors, roofs and walls at period properties in London.

While the large feature windows of a more modern block in east London were also proven to offer poor insulation during the colder months.

 Heat loss through large feature windows of a modern flat in Shoreditch, London
Cat

The images were captured on a Cat S61 smartphone with a built-in thermal imaging camera as part of a project studying insulation at homes throughout the country.

Generally the newer houses held their heat more efficiently, but one image taken in Shoreditch showed heat loss through the large feature windows of a trendy modern flat.

Another image taken in north London showed the stark contrast between a Victorian block of flats and a recently completed modern block built next door.

The thermal image shows heat being lost through the windows and walls on the old building while the external walls of the modern block are cold - showing the heat being kept inside.

Well-insulated walls and roof of a new-build adjacent to a poorly insulated Victorian building in London (Cat)

Paul Holmes, Technical Product Manager at Bullitt Group, makers of the Cat S61, said: “When looking at a building using thermal imaging, it’s the contrasting colours that are important to focus on. Yellow and white/yellow spots show heat, and dark plum colours show cold spots. Both of these can be a bad sign because it usually means that either heat is escaping or cold is coming in.

“The lighter or brighter a patch is, the hotter it is, and the bigger the colour difference the bigger the difference in temperature.

“Equally, from the outside of the house it’s important to take note of particularly warm spots as this could be a sign of heat escaping. In general, the goal is for the exterior of your house to be cold – including windows, external walls and the roof – as this means that the heat is staying inside rather than leaking out.”

Increasing insulation in the home can improve energy efficiency.

Britain's Energy Saving Trust recommends insulating roofs, lofts and walls and installing draught-proofing as effective ways to significantly reduce heat loss while lowering bills.

Installing loft insulation can reduce bills by up to £225, according to Which?.

A spokesman for Cat phones said: “Even the best insulated homes will leak heat particularly at this time of the year when many of us have our central heating on day and night.

“Working out where in your home you have a problem is not always easy and can be a costly exercise if you have to call in the experts.

“Lots of our customers are turning to the Cat S61 to spot where they’re losing heat and then fixing the issue themselves.”