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How to use a thermal imaging camera

Updated: October 2026

The camera is charged, the house is warm, and a bright patch on the screen is about to be treated as a fact. How to use a thermal imaging camera, on the six models in this amazon.co.uk set, is mostly about the weather, the scale and the surface before you trust a colour. Peter F. used those listings and public UK guidance on 16 October 2026. There was no visit to your house and no lab test of the cameras in the [thermal camera comparison](/hub/measuring-equipment/thermal-camera). You should be able to take a picture you can compare with the next one, and you should know when the number is a reason to stop.

The camera is charged, the house is warm, and a bright patch on the screen is about to be treated as a fact.

Our top picks

Thermal Master Thermal Master Thor 002

Best overall

Thermal Master Thermal Master Thor 002
9.0/10about £359
View offer
GOYOJO GOYOJO GW192A

Preis-Tipp

GOYOJO GOYOJO GW192A
8.6/10about £129
View offer
BSIDE BSIDE HX3

Alternative

BSIDE BSIDE HX3
7.8/10about £139.99
View offer
On this page
  1. 1.Wait for a real temperature gap
  2. 2.Read the scale, not the palette
  3. 3.Emissivity, glass and metal
  4. 4.Where a professional takes over

Wait for a real temperature gap

A summer afternoon with sun on the brick will draw a picture of the sun, not of the insulation. Which? puts a useful DIY gap at about 10 °C between inside and outside, with the home around 19–20 °C and the outside below about 10 °C. NHBC adds the outdoor limits: no direct sun on the face you are scanning, no rain, and no high wind. Scan inside when you can. An internal wall fights the weather less than a sunlit gable. If you do go outside, pick a still, dull morning. Never aim the lens at the sun. Reading a heat-loss pattern, as distinct from the button craft, continues on the thermal camera for heat loss page.

Read the scale, not the palette

The camera will stretch its colours across whatever temperatures are in the frame. Auto scale is why two pictures with the same rainbow can mean different things. A loft hatch that fills the frame may look dramatic because the scale has only a few degrees to work with. The same hatch in a wide shot of the landing may look mild because a cold window has pulled the scale wider. Compare plaster with plaster, and the cold corner with the middle of the same wall. Fifteen colours, which the HX1 and the HX3 advertise, change how the step looks. They do not add detector pixels. If you are choosing a camera, the native pixel order is on the thermal imaging camera buying guide.
Thermal Master Thermal Master Thor 002

Testsieger

Thermal Master Thermal Master Thor 002
9.0/10about £359
View offer

Emissivity, glass and metal

The number on the screen assumes the surface emits infrared in a particular way. Ordinary painted plaster is often treated, as a rule of thumb in training slides, near an emissivity of 0.95. That is not a measured value for your wall. Bare metal, foil and glass reflect the surroundings, so the camera can report the room behind you, or the sky, instead of the pipe. Three listings say you can adjust emissivity: the AMPBANK M192, the BSIDE HX3 and the Minhe. The HX3 names presets that include concrete and water. The GOYOJO, the HX1 and the Thor 002 do not state a control. A wrong emissivity moves the number even when the warmer and cooler pattern is real.

Where a professional takes over

Stop when the picture is being asked to do a job it cannot do. A cold patch can be missing insulation, a bridge, air leakage, or damp. RICS says suspected damp should be checked with a moisture meter. At work, the Electricity at Work Regulations 1989 still apply. The UK Thermography Association says professional electrical thermography should not use a phone clip-on. A client report or a house purchase needs a competent person. BS EN ISO 6781-1:2023 is the current detection standard. The older BS EN 13187 was qualitative and did not rate the insulation. None of these listings is a certificate under either document. A qualifying purchase through our links can earn a commission at no extra cost to you.

Common questions

How cold does it need to be outside?
For a DIY look, Which? and RICS both use a gap of about 10 °C between inside and outside. A house around 19–20 °C and an outside below about 10 °C is the Which? picture. A formal survey may hold 20–22 °C indoors for about 72 hours. That soak is for the surveyor. Sun, rain and high wind spoil the outside face, which is why NHBC tells operators to avoid them.
Should I scan inside or outside?
Inside is the more repeatable scan, because the wall is less at the mercy of sun and wind. Outside can show a whole elevation on a dull, still morning if the gap is real. Keep each comparison to one kind of surface, and do not mix a sunlit gable with an internal landing and then treat the colours as the same scale.
Why do two pictures with the same colours mean different things?
Because auto scale stretches the palette across the temperatures in that frame. A hatch shot on its own can look severe when the scale only covers a few degrees. The same hatch beside a cold window can look mild. Read the numbers at the ends of the scale, and write them down, before you compare two visits.
How do I measure a shiny pipe?
Set emissivity if the camera allows it. In this set the AMPBANK M192, the BSIDE HX3 and the Minhe say you can. If yours does not state that control, stick a small piece of tape on the pipe and read the tape, which is the usual workaround for a reflective surface. The bare metal is often showing a reflection of the room.
How close should I stand?
Loan instructions for one council scheme say about 1 to 1.5 metres for their camera. These six listings do not print a stand-off distance, so treat 1 to 1.5 metres as that scheme's rule of thumb, not as a specification. Close enough to fill the frame with the patch, far enough that you are not only seeing your own reflection.
Can I scan the consumer unit?
You can look at the closed outside of a cupboard as a private check. You should not open a live consumer unit, and a phone module is not kit for a professional electrical survey. The UK Thermography Association rules that clip-on out. Workplace electrics stay under the Electricity at Work Regulations 1989.

Related pages

Moisture meter comparison

Thermal camera

Best thermal imaging camera UK for your actual job

Thermal imaging camera buying guide on native pixels

Thermal camera for heat loss on cold walls and hatches

Phone thermal camera vs handheld with its own screen

Sources

NBS, BSI, NHBC, RICS, the UK Thermography Association, the Electricity at Work Regulations 1989 and Cambridge Carbon Footprint loan-scheme training, plus the amazon.co.uk listings read on 16 October 2026. Prices move. Nothing was calibrated in a lab.

  1. NBS, BS EN ISO 6781-1:2023 (retrieved 16 October 2026)
  2. BSI, BS EN 13187:1999 (retrieved 16 October 2026)
  3. NHBC, thermal imaging report guide (retrieved 16 October 2026)
  4. RICS, an introduction to building thermography (retrieved 16 October 2026)
  5. UK Thermography Association, electrical thermography (retrieved 16 October 2026)
  6. Electricity at Work Regulations 1989 (retrieved 16 October 2026)
  7. West Devon, thermal imaging camera user guide (retrieved 16 October 2026)
  8. FLIR, infrared camera accuracy and uncertainty (retrieved 16 October 2026)
  9. Cambridge Carbon Footprint, thermal imaging training slides (retrieved 16 October 2026)
  10. Red Current, electrical thermal imaging FAQs (retrieved 16 October 2026)