Ranking updated
How to find heat leaks at home with a thermal camera
The radiator is hot, the room is still cold and you cannot tell where the warmth goes. A thermal camera shows it as colour: the blue streak under the door, the cold corner behind the wardrobe, the window frame that never sealed.
A scanning routine, then thermal camera apps. A phone needs a plug-in thermal camera for this; the app alone cannot see heat. If a socket, switch or fuse box looks hot, stop using it and call a qualified electrician. Do not open electrical panels yourself.
Pick the right moment
Leaks stand out when it is much colder outside than in. Scan in the evening or early morning with the heating running. Compare camera apps in thermal camera apps.
Scan slowly, compare fairly
Move along window frames, door edges, skirting boards and ceiling corners. A spot only matters if it is clearly colder than the wall right next to it. Shiny surfaces like glass and metal can fool the camera.
Keep a fix list
Photograph each cold spot with a note on where it is. Draught strips and window seals are often a weekend job; damp or insulation problems need a builder. To track the jobs, see how to keep track of home maintenance.
Plan for the cold months
A warmer home holds heat longer when the power goes out; see how to prepare for a power outage. To automate heating, see how to start a smart home.
| Step | What you do | Why |
|---|---|---|
| 1. Cold day | heating on for a while | leaks show clearly |
| 2. Scan inside | windows, doors, corners | where heat escapes |
| 3. Compare | cold spot vs the wall | not just a colour |
| 4. Photograph | save each finding | a list to fix |
| 5. Easy fixes first | seals, draught strips | quick wins |
Frequently asked questions
Can my phone be a thermal camera?
Only with a plug-in thermal camera. The phone’s normal camera cannot see heat.
When is the best time to look for heat leaks?
On a cold day with the heating on, when the difference between inside and outside is large.
What if a socket shows up hot?
Stop using it and call a qualified electrician.