Handheld Infrared Thermometers
What is a handheld infrared thermometer?
Thermometers have been available for hundreds of year and are reliable devices. Unfortunately, most of them need to stay on a specific place at least 10 minutes to accurately measure temperature. Most do not have probes or any other possibility to measure temperature in a specific part of a room or on an appliance.
Handheld infrared thermometers have are highly useful. Battery powered, compact and with good enough accuracy, can be held in one hand and pointed to any area no matter how large or small, from a distance or close-by. The measured value is shown on a small display continuously or only when triggered, being extremely easy to use.
The greatest advantage of such a device is that it can show, in a couple of seconds, issues in uniform cooling or heating on certain devices, thermal losses, with no training and in a straightforward matter. The measured area is highlighted by a laser pointer on some devices, making identification very easily.
Features
There are varied infrared thermometers. Some offer basic functionality while others include additional costly features such as live thermal imaging. The most simple ones are affordable and useful enough if they have some minimal capabilities. While largely similar, medical devices are not preferred since they may be more accurate but lack an useful laser pointer to indicate the measured area.
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While there are many brands and models, a good product should have the following capability:
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Utility
The actual performance of a building envelope and the resulting comfort of its occupants depend on a relatively stable, continuous temperature in most areas. Finding places that influence airflow, such as cold or hot spots, can point at where remediation procedures must be concentrated. Space heating and cooling imbalances can be easily spot, potentially saving more energy.
On appliances, large temperature differences may be normal such as on large cooking, refrigeration or conditioning equipment. However, all large temperature differences may create poor device performance, affect nearby furniture or have other undesirable effects that have to be considered. Ideal locations can be found by comparing temperature measurements.
Note that both the initial state of the device, normal and full load conditions can be easily determined and compared with previous days and various mitigations, ensuring effective solutions can be found in time. The focus is on reducing large temperature swings with subsequent measures.
Typical testing scenario
Various temperature readings are made on a room, to determine where heat losses or heat gains manifest. Improper or no sealing on doors and windows can be found. For devices that get hot during use, high temperature concentrated in a specific place points at poor airflow and need to rearrange nearby furniture.
| Location | Ambient temperature | Highest temperature | Lowest temperature | Comments |
|---|---|---|---|---|
| 12000 BTU Air conditioning unit (on cooling) | 5 minutes | 5 W (standby), 60 W (high fan), 1060W (powered on) | 100-300 kWh | Full power load reached in 5 minutes |
| 300l Refrigerator (Freezer set at -18 Degrees Celsius) | 5 minutes | <1 W (standby), 100-300 W (powered on) | 36-72 kWh | Temperature must be lowered from normal to trigger start compressor |
| Cooking machine | 5 minutes | <1 W (standby), 40 W (high fan), 2000 W (oven), 1500 W (grill), 1000 W (large/fast burner), 800 W (medium burner), 600 W (small burner) | 10-70 kW/h | No comment |
| Classic small oven | 1 minute | 0 W (standby), 1500 W (powered on) | 8-16 kW/h | No standby load due to no electronic control |
| Microwave oven | 1 minute | 1 W (standby), 1000 W (on), 1200 W (grill) | 8-16 kW/h | No comment |
| Grill | 1 minute | 2000 W (powered on) | 10-27 kW/h | No standby load, rarely any power control |
| Toaster | 1 minute | 600 W (low), 1200W (high) | 3-6 kW/h | No standby load due to no electronic control |
| Electric Kettle | 1 minute | 1800-3100 W (powered on) | 10-25 kW/h | No standby load, no power control |
| Desktop computer | 3 minutes | 8 W (standby), 40 W (idle), 100-400 W (full load) | 10-24 kW/h | Display power load should be measured separately |
| 50 inch TV | 3 minutes | 1 W (standby), 40 W (half brightness), 90 W (high brightness) | 9-19 kW/h | Note that older TVs have no backlight control |
| Laptop | 3 minutes | <5 W (standby), 40 W (idle), 100 W (full load) | 5-7 kW/h | Power load slightly higher if battery recharges |
| Washing machine | 1 hour | 2-4 W (standby), 50-155 W (washing), 250 W (800rpm centrifugation), 1500 W (washing with heating) | 11-18 kW/h | No comment |
| Compact (travel) hairdryer | less than 1 minute | 560 W (half), 1100 W (full) | 5-8 kW/h | No standby load |
| Older Vacuum cleaner | less than 1 minute | 220 W (lowest), 1300 W (highest) | 5-9 kW/h | Appliance has power control |
| Newer Vacuum cleaner | less than 1 minute | 100 W (lowest), 600 W (highest) | 2-4 kW/h | Appliance has power control |
| Iron | less than 1 minute | 1600-2100 W (depending on product) | 5-6 kW/h | No power control |
| LED desk lamp | less than 1 minute | 2-10 W (typical) | 1-2 kW/h | Some lamps have brightness control |
Hot or cold spot temperatures may be relative. Note that first readings may be different from ones made after two or three minutes, as some affordable infrared thermometers may not have proper recalibration.
Monitoring time
Readings can be made at any time. Ensuring that some are done in worst conditions such as high occupancy, intense activity, very cold winter day, very hot summer day, high humidity, intense sun, some doors and windows closed or opened, creates enough scenarios to test various improvements.
Flexibility
Monitoring temperature anytime and anywhere, particularly in hard to reach locations, as close as a few centimeters or as far as a few meters, even if measurement accuracy may not be ideal, is extremely important.
Note that also particular food processing or other small manufacturing processes can be monitored on sample products with this device so its usefulness extends greatly beyond typical scenarios.