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infrared thermometers

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  • I don't sell any of these nor do I receive any remuneration if you buy them, and I have not personally reviewed all of them, they are listed here to give you perspective


  • infrared thermometers allow you to ascertain the temperature of objects from a distance by measuring the infrared wavelength of light that they are emitting
  • this page only discusses those devices which just give a temperature readout rather than a visual heat map and temperature read out - for these see thermal imaging cameras
  • the temperature range will vary depending upon the device:
    • those designed for human foreheads will only go to 50degC in general even in “object” mode but are far more accurate than most industrial devices
      • human skin has an emissivity of 0.95-0.99 but these forehead thermometers use an emissivity of around 0.78 in human mode to give a reading that approximates oral temperatures
      • when set to object mode they presumably use an emissivity of 0.95
    • medium temperature “industrial” / BBQ models may have a temperature limit of around 500degC
    • high temperature industrial ones will have a wide range of temperature from minus 50degC to 1500degC
  • industrial ones usually have:
    • 1 or 2 lasers to help aim the device
    • ability to set the emissivity from 0.1 to 1.0
    • a narrow “angle of view” which is measured as distance to spot (D:S) ratio
      • wider ones for general use are 16:1, more industrial very high temp usage are 30:1 allowing you to stand 3m away to measure a 10cm area
      • 12:1 models are generally best at 36cm distances from objects
    • newer sensors have a faster response time of under 250msec, older ones are 500msec
    • more expensive ones will be drop proof to 3m and water-resistant
  • industrial IR thermometers are NOT good for assessing fevers as they are NOT sufficiently accurate, even the better ones have an accuracy of only ±1.8°C and that assumes you have ascertained the correct emissivity value!
  • in fact they are NOT very accurate for most of your needs of ambient temperature measurements where a +/- 2 degC error when measuring something at 20degC can give a measure anywhere from 18-22degC - probably NOT useful
  • where they are great is for measuring very hot temperatures and a few degrees out does not make any difference for most uses.
  • the device will need to have the emissivity set for the type of material you are measuring otherwise you will get inaccurate results
    • for many objects, their emissivity CHANGES significantly with major changes in temperature!
  • SOME devices have a FIXED emissivity of 0.95 which you cannot change limiting its versatility greatly!
    • they are however adequate for most non-reflective non-metal surfaces, and painted or non-reflective coated metals
    • eg. Klein IR1 as emissivity set to 0.95; HoldPeak HP-960C for cooking;
  • to ascertain the emissivity you can either:
    • use a table look up
      • for most materials, emissivity is the opposite of reflectivity
      • unoxidised aluminium = 0.02-0.03 depending on temp
      • oxidised aluminium = 0.11-0.19 depending on temp
      • polished stainless steel = 0.07
      • matte stainless steel / aluminium = 0.2-0.3
      • unoxidised cast iron = 0.21
      • gravel = 0.28
      • water = 0.67
      • moderately oxidised cast iron = 0.65-0.78 depending upon temp (strongly oxidised = 0.95)
      • snow = 0.82-0.89
      • glass = 0.92-0.94
      • most non-reflective non-metals = 0.95
      • cooking oil = 0.95
      • ice = 0.95
    • measure it by comparing with contact probe:
      • heat a target object well above room temperature and measure it by a trusted contact probe and via IR making sure the IR is not detecting the probe itself (best to remove the probe)
      • ensure there are no hot objects nearby that could cause reflections that interfere with the measurement
      • The surroundings of the object should have the same temperature as the sensor ie. don't measure it inside an oven
      • Adjust the emissivity setting on the IR sensor until it measures the same temperature as the contact probe
    • measure it by painting part of it matte black:
      • paint part of it with matte black BBQ paint
      • heat the object as above, measure the painted area at emissivity 0.95 then adjust emissivity whilst measuring non-painted area to get the same temperature reading.

wide temperature range devices for really hot objects at a distance

  • HoldPeak HP-1800C
    • -50~1800℃ (-58~3272°F)
    • 50:1 D:S thus designed for being around 5m or more from object
  • HoldPeak HP-1500C
    • -58°F - 2732°F (-50°C - 1500°C)at +/- 2% accuracy above 0degC (+/- 4°C below 0°C), resolution: 0.1°C under 1000°C, 1°C over 1000°C
    • <250msec response time
    • 30:1 D:S
      • 30cm = 1cm spot; 1.5m 20-30cm spot; 3m 10cm spot; 9m 30cm spot; 15m 50cm spot
    • dual LED flashlights
    • dual laser beams
    • backlight; 9V battery, 160g, 7.6 x 3.75 x 2.5 inch
    • HP-1500APP version gives Bluetooth smartphone control $AU84
    • older model, HP-1420C has older sensor and measures to 1420degC
  • HoldPeak HP-985B
    • as for HoldPeak HP-1500C however:
      • -50℃~1360℃(-58℉~2480℉) accuracy ±3°C
      • 16:1 D:S makes it more useful for cooking than a 30:1 model as you only need to be 1.6m for a 10cm spot not 3m away, 0.7m gives a 4cm spot, 2m gives a 13cm spot;
  • UT303D
    • -32°C – 1250°C; 250ms with single spot laser; 30:1 D:S; 9V or can be powered by USB; 322g;
    • $AU188

reduced temperature range devices

  • Mestek IR01D
    • -50℃~800℃, ±1.5% + 2℃; 12:1; 500msec; 2xAAA;
    • color screen, ambient temp thermometer (takes 30min to adjust) and humidity meter; $AU40
  • FLUKE 62 MAX+ IR
    • -30 C to 650 C (-22 F to 1202 F); 12:1;
    • 300ms
  • UT309C
    • -35 ~ 650°C ( -31 ~ 1202°F) ≥0°C: ±1.8°C or ±1.8% of reading
    • 12:1 D:S
    • dual laser; 250ms response;
    • 3m drop proof; IP65; 32mm × 29mm LCD; 292g; 189mm × 118mm × 55mm; 9V battery; $AU119
  • HP-985C-APP
    • as for HoldPeak HP-985B however:
      • -50 C to 800 C ( -58 to 14720 F ) accuracy 0-100°C = ±2°C and above 100°C = ±3°C
      • 500msec response
      • Bluetooth
  • HoldPeak HP 980D-APP
  • Klein IR5

Dual IR and probe devices

devices designed for cooking

  • Inkbird Ink-IFT01
    • -50℃ to 550℃ at ±2°C accuracy; 500ms; 12:1 DS; 1 laser; 3cm spot at 36cm; 9V battery; $AU33
  • HoldPeak HP-960C
    • designed for holding 3-4cm from food or cooking surface but will not be adequate for wood-fired oven pizzas which need 450degC
    • -30℃~275℃ (-22~527℉)
    • read out within 0.5sec; no laser pointer; preset emissivity;
    • finger-sized 3.3x 0.6×0.8in (84x16x20mm); Weight:30g; Two 1.5V(LR-44) button batteries;
australia/irthermometer.txt · Last modified: 2022/07/28 19:32 by gary1

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