Could a thermal camera reveal your home’s hidden heat loss?

It’s like X-ray vision – for heat loss. Last year, web engineer Jamie Matthews bought a thermal imaging camera. His home, in the southeast of England, was about to give up some of its secrets.

The colourful images on the device’s small screen soon revealed how his loft hatch was letting him down.

“That was really obvious on the camera,” he says, explaining that he could see cool areas on the hatch, where heat was apparently escaping.

Mathews, who runs a software company that supplies the clean tech industry, also found some other small gaps in external walls and parts of his roof that appeared less well insulated than others.

“It’s good fun and it certainly shows up things that may not be immediately obvious,” he says.

While Matthews was able to draught-proof some areas himself, he says he would take a more methodical approach if he were planning any major changes to his home. The web engineer later had a professional heat loss survey carried out when he installed a heat pump, for example.

That approach is sensible, according to building physics researchers who spoke to the BBC. There are signs that thermal cameras are becoming more popular, as homeowners seek to slash their heating bills and carbon emissions. Local councils are increasingly allowing residents to borrow the devices for free, for example.

But there is no substitute for professional advice if you are planning big works or interventions, experts say.

Thermal cameras work by using a sensor to detect infrared light, which we cannot see, but which we can sometimes feel as heat. Such devices aren’t cheap. Matthews spent roughly £160 on his, though organisations including local councils and energy supplier Octopus Energy do loan them out to people free of charge so that they can gain a basic understanding of heat loss in their homes.

Wiltshire Council recently made 11 devices available to borrow from local libraries, as well as a brief guide on how to use them. There has been “huge uptake” says Cllr Ian Blair-Pilling, such that the council now has a waiting list for interested residents.

«Expert advice, combined with a measured approach to the findings from thermal imaging, will give residents the best chance of making informed decisions about energy-saving home improvements,» says Cllr Blair-Pilling.

Small interventions could help people keep their homes warm and reduce the risk of cold-related health conditions, he adds.

However, Jo Atkinson, senior consultant in buildings decarbonisation at Energy SysteCatapult, a research organisation, expresses concern over the growing availability of thermal cameras: “In my opinion, the risks are too great for making the wrong choices.”

It is possible to misinterpret thermal camera images, she says, noting that if a wall has been warmed by the sun, an image of that wall taken outside could make it look as though heat is escaping, when it is not. Reflective surfaces can also appear, misleadingly, to be leaking heat.

While using a thermal camera as a starting point for understanding your home is “absolutely fine”, according to Ronita Bardhan at the University of Cambridge, it is important to ask for independent expert advice when planning any renovation works.

Thermal camera imagery can make it look as though some areas of your home are losing a lot of heat, but this might simply be a result of how the camera has been calibrated, how the user holds it and moves it around, and which colour palette was chosen for the display.

Dr Bardhan adds that there is a risk of triggering “retrofit anxiety” in homeowners.

Plus, if people go on to alter their insulation, for example, such measures should be taken with great care as improper installation can cause damp and mould.

North Somerset Council provides thermal cameras to residents, on loan, and this scheme is also currently operating on a waiting list basis due to its popularity. The Council has published introductory advice on how to use the cameras, including an online video.

The Centre for Sustainable Energy (CSE), a charity, highlights a more detailed guide from the National House-Building Council, which describes how to use thermal cameras. However, a CSE spokeswoman adds that the organisation still recommends people seek expert advice.

Phil Steele, future technologies evangelist at Octopus Energy, agrees: “You have got to be careful.” Thermal cameras can, for instance, make the corners of roolook very cold but this is simply a reflection of reduced air circulation in those areas, rather than an insulation problem, he explains.

Octopus Energy has around 500 cameras that it loans out to customers every winter. Last year, the firm distributed the devices roughly 3,800 times.

Владельцы домов с тепловизионными камерами, которые общались с BBC, такие как Мэтьюз, говорят, что они отнеслись к снимкам с осторожностью.

Луиза Грин, дизайнер из Лондона, говорит, что она прочитала онлайн-учебные материалы, прежде чем использовать тепловизионную камеру для поиска точек потери тепла в доме вскоре после того, как они с партнером переехали.

В ее случае мисс Грин арендовала камеру в Library of Things, общественной организации, которая предоставляет людям различные материалы для временного пользования. Устройство указало на потерю тепла вокруг окон и дверей в доме мисс Грин. Она и ее партнер смогли сравнить результаты с более изолированным жильем своего соседа.

«Это просто подтвердило то, что мы уже знали, но все равно было интересно посмотреть, знаете ли, есть ли другие области?» — объясняет она.

Даррелл Тейлор из Flir, фирмы, производящей тепловизионные камеры, говорит, что граждане могут получить доступ к некоторым бесплатным учебным материалам на веб-сайте его компании.

Он добавляет, что Flir стремится сделать тепловые изображения максимально четкими и простыми для интерпретации, в том числе путем объединения оптических изображений с тепловизионными, чтобы добавить больше деталей к окончательному изображению. И он предполагает, что в будущем камеры Flir могут предлагать основанные на машинном обучении инструкции и советы по использованию устройств.

Однако те, кто знает, как лучше всего интерпретировать изображения тепловизионной камеры, могут обнаружить необычайно скрытые проблемы в здании.

Недавно доктор Бардхан взяла камеру с очень высоким разрешением на осмотр дома, который она собиралась купить. Но тепловизионные изображения показали трещины в стене, которые позже оказались признаками проседания.

«Это, вероятно, не было бы обнаружено, если бы я не зашла и не увидела это», — говорит она. Доктор Бардхан решил не делать предложение по недвижимости.