Full Extech Instruments Range
Thermal imaging is one category in a much larger Extech test and measurement range supplied by Ecotao – multimeters, clamp meters, moisture meters, air quality, water quality and more.
VIEW THE FULL EXTECH RANGE →Thermal Imaging Cameras
A thermal imaging camera converts the long-wave infrared radiation emitted by every object above absolute zero into a false-colour image in which each pixel carries its own temperature value. Ecotao supplies thermal imaging cameras and infrared measurement instruments from our Cape Town base to South Africa, Namibia, Botswana, Zimbabwe, Mozambique, Lesotho and Eswatini.
The measurement is entirely passive. Infrared energy in the 8 to 14 micrometre band is focused onto an uncooled microbolometer array – typically vanadium oxide – where each element changes electrical resistance in proportion to the energy it absorbs. The camera converts that resistance change into an apparent temperature, applies an emissivity correction, and renders the result as an image. Because nothing is emitted by the instrument, a thermal camera needs no illumination and works in complete darkness, through smoke and through light airborne dust.
What this buys you in practice is a way to find a fault you cannot see and did not already know the location of. An infrared thermometer gives you one averaged reading at a spot you have already chosen. A 256 x 192 thermal camera gives you 49,152 simultaneous readings across the whole scene, so the loose termination, the failing bearing, the blocked photovoltaic string or the damp patch behind the plaster announces itself as a bright region rather than waiting to be guessed at.
A note on the Extech thermal camera range
Extech no longer lists a thermal imaging camera in its current catalogue. The Industrial Imaging & Inspection category on extech.com now covers thickness gauges, videoscopes and vibration meters only, and the former Extech imagers – the i5, i7, IRC30 and IRC40 – have been withdrawn. The IRT600 thermal condensation scanner is marked discontinued, with the Extech VIR50 named as its replacement.
For thermal imaging, Ecotao supplies the HT-18+ and HT-04D cameras described below. The Extech infrared instruments that remain current are listed further down the page.
Thermal imaging cameras supplied by Ecotao
HT-18+ Thermal Imaging Camera
The HT-18+ is the camera to reach for when the target is small, hot, or too far away to approach safely. Its 256 x 192 vanadium oxide array delivers 49,152 measurement points through a 12 micrometre pixel pitch, which is what lets it resolve an individual terminal on a crowded distribution board from outside the arc-flash boundary rather than averaging three terminals into one warm blur.
Thermal sensitivity of 50 mK or better means it separates surfaces that differ by five hundredths of a degree – the margin that matters on low-contrast building and insulation work. The 550 °C ceiling covers severely overheating terminations and process plant that would saturate an entry-level instrument, and thermal-to-visual fusion in 25% steps keeps component outlines and labels legible in the saved image, so a report still makes sense to a client who was never on site.
- IR resolution256 × 192 (49,152 px)
- Thermal sensitivity≤50 mK @ 25 °C
- Range−20 to +550 °C
- Field of view56° × 42°, IFOV 3.75 mrad
- Refresh rate≤25 Hz
- CaptureJPEG + MP4, 4 GB
HT-04D Entry Level Thermal Imager
The HT-04D is built for work you can walk up to. Its 160 x 120 array takes 19,200 simultaneous readings, which is ample resolution for distribution boards, motors, bearings, HVAC plant and building envelopes inspected from a few metres, and its 0.07 °C sensitivity is fine enough to trace damp and missing insulation where the differences are fractions of a degree.
The trade-offs against the HT-18+ are deliberate and worth understanding before choosing. The 300 °C ceiling is generous for building and light electrical work but will clip on badly overheating terminations or furnace-adjacent plant. The 9 Hz refresh is fine for static targets but lags when panning across a scene, and the 0.5 m fixed minimum focus rules out close-up work on small components. In return you get a lighter, simpler instrument with 3 GB of storage that a technician can be trained on in an afternoon.
- IR resolution160 × 120 (19,200 px)
- Thermal sensitivity0.07 °C
- Range−20 to +300 °C
- Field of view35° × 26°
- Refresh rate9 Hz
- CaptureJPEG, 3 GB
Extech VIR50 Dual Laser IR Video Thermometer
The VIR50 is not a thermal imager and should not be bought as a substitute for one – it measures a single spot, not an array. What it adds over an ordinary infrared thermometer is a built-in 640 x 480 visible-light camera and a colour display, so every reading can be saved to microSD as a photograph or video with the target visibly identified. That closes the most common gap in infrared thermometer work, where a number in a notebook cannot later be tied to the component it came from.
Its real advantage over an entry-level imager is range and reach. It measures to 2200 °C, far beyond any handheld thermal camera in this class, and its 50:1 distance-to-target ratio resolves a 25 mm spot at roughly 1.27 m, where the dual lasers converge to mark exactly what is being measured. That combination suits furnace, kiln, boiler and foundry work in which the temperatures involved would simply saturate an imaging camera.
- RangeUp to 2200 °C
- Distance to spot50:1
- Camera640 × 480 VGA
- Emissivity0.10 to 1.00 adjustable
- TargetingDual converging laser
- CaptureJPEG + 3GP to microSD
HT-18+ vs HT-04D vs Extech VIR50 compared
The choice between these three comes down to one question: do you need to find a thermal fault, or do you already know where it is and need to measure it? The two cameras find; the VIR50 measures.
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| Specification | HT-18+ | HT-04D | Extech VIR50 |
|---|---|---|---|
| Instrument type | Thermal imaging camera | Thermal imaging camera | Spot IR thermometer with video |
| Measurement points | 49,152 | 19,200 | 1 |
| IR resolution | 256 × 192 | 160 × 120 | Not applicable |
| Visual camera | 640 × 480 (0.3 MP) | 640 × 480 (0.3 MP) | 640 × 480 VGA |
| Thermal sensitivity | ≤50 mK @ 25 °C | 0.07 °C | Not applicable |
| Temperature range | −20 to +550 °C | −20 to +300 °C | Up to 2200 °C |
| Accuracy | ±2% rdg or ±2 °C | ±2% rdg or ±2 °C | ±0.5% or 1 °C repeatability |
| Detector | Uncooled VOx FPA, 12 µm | Uncooled microbolometer | Single-element thermopile |
| Field of view | 56° × 42° | 35° × 26° | 50:1 distance-to-spot |
| Refresh rate | ≤25 Hz | 9 Hz | Not applicable |
| Image fusion | Yes, 25% steps | No | No |
| Video recording | Yes, MP4 | No | Yes, 3GP |
| Storage | 4 GB built-in | 3 GB built-in | microSD card |
| Emissivity | 0.10 to 1.00 | 0.10 to 1.00 | 0.10 to 1.00 |
| Contact probe | No | No | Type-K bead wire included |
| Best suited to | Electrical, solar PV, mechanical, standoff work | Building, HVAC, damp, close-range electrical | Furnace, kiln, foundry, documented spot checks |
How to choose a thermal imaging camera
1. Start with detector resolution, not display size
Resolution is the specification that cannot be worked around later. A large, bright screen showing an interpolated image from a small detector looks impressive and measures poorly. What matters is the instantaneous field of view: the angular size of one detector element. The working rule in thermography is that a target should cover roughly three by three detector pixels before its reading can be trusted, because anything smaller has its temperature averaged with whatever surrounds it. This is why the same camera that reads a motor casing accurately at 5 m will under-read a 10 mm cable lug at the same distance. If you can walk up to your targets, 160 x 120 is enough. If you are working from a ladder, a roof edge, or outside an arc-flash boundary, 256 x 192 is the practical floor.
2. Match temperature range to your worst case, not your typical case
A camera that saturates gives you no reading at all, and the case where that happens is exactly the case you most needed to measure. A distribution board termination in normal service sits comfortably under 100 °C; one that is about to fail can run several hundred degrees above ambient. Choosing a 300 °C instrument because normal readings fall well within it is a common and expensive error. If your work includes electrical fault-finding, process plant or anything combustion-related, specify to the failure condition.
3. Treat NETD as a building-work specification
Noise equivalent temperature difference is the smallest temperature step the detector can distinguish from its own electronic noise, quoted in millikelvin, where lower is better. It matters enormously on low-contrast work – envelope surveys, damp tracing, underfloor heating, insulation verification – where the whole finding is a fraction of a degree. It matters far less on electrical work, where a failing joint may sit 30 °C above its neighbours and any detector in this class will see it clearly. Do not pay for sensitivity you will never use, and do not skimp on it if buildings are your main application.
4. Decide whether fusion is a reporting requirement
A thermal image of a busy panel, viewed on its own a week later, is a field of coloured blobs that is genuinely difficult to map back to physical hardware. Image fusion overlays visible-light detail – edges, labels, breaker numbering – onto the thermal data so the image stays interpretable. If your findings are read by a client, a landlord, an insurer or a maintenance planner who was not standing next to you, fusion stops being a convenience and becomes the difference between a usable report and an argument.
5. Plan for emissivity before you plan for anything else
Every reading a thermal camera produces is an apparent temperature that depends on the emissivity setting being right for the surface. Get it wrong on bare metal and the error can be enormous. The table below lists working values for surfaces commonly encountered in South African electrical, building and industrial work.
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| Surface | Typical emissivity | Practical note |
|---|---|---|
| Polished copper busbar | 0.03 – 0.05 | Effectively a mirror in the infrared. Never measure directly – apply tape. |
| Oxidised / weathered copper | 0.60 – 0.80 | Improves with age, but still variable across one busbar. |
| Polished aluminium | 0.05 | Same problem as copper. Common on switchgear enclosures. |
| Anodised aluminium | 0.77 | Usable, but confirm against a contact reading if the value is critical. |
| Polished stainless steel | 0.15 | Widespread in food and beverage plant – a frequent source of bad data. |
| Galvanised steel | 0.28 | Roof sheeting and cable tray. Low enough to need correction. |
| Heavily oxidised steel | 0.80 | Reads reasonably at default settings. |
| PVC cable insulation | 0.90 – 0.93 | Reliable. Measure the insulation, not the exposed conductor. |
| Matt black electrical tape | 0.95 | The standard reference patch. Allow it to reach equilibrium first. |
| Painted surfaces (any colour) | 0.90 – 0.95 | Paint colour barely affects infrared emissivity. |
| Concrete and plaster | 0.92 – 0.95 | Well behaved for building envelope work. |
| Face brick | 0.90 – 0.95 | Reliable, though thermal mass delays visible patterns. |
| Glass | 0.85 – 0.95 | Opaque in long-wave IR – it reflects you, it does not show what is behind it. |
| Water | 0.95 – 0.98 | Very close to a black body. Excellent for leak tracing. |
| Asphalt / bitumen roofing | 0.90 – 0.95 | Good target for flat-roof moisture surveys after sunset. |
What thermal imaging is used for in South Africa
Electrical distribution and switchgear
A high-resistance connection dissipates power as heat long before it fails, so it is visible thermally for weeks or months while remaining invisible to inspection. Thermography finds loose terminations, corroded lugs, undersized conductors, imbalanced phases and overloaded breakers while the board is under load and still closed – the survey happens without an outage and without opening the enclosure to a live front. The extended switching cycles that South African distribution equipment has been subjected to in recent years make this a particularly productive inspection: each de-energise and re-energise cycle thermally stresses connections that were never designed for frequent load transitions, and the resulting loosening shows up thermally first.
Solar photovoltaic installations
A failing PV cell, a cracked interconnect or a shaded and reverse-biased string does not simply produce less power – it dissipates the surrounding string's power as heat and appears as a hot spot against an otherwise uniform panel. Thermography identifies which panel and often which cell is responsible in a single pass across an array, which is faster and safer than string-by-string electrical testing on a roof. With rooftop and ground-mount PV now widespread across South Africa, this has become one of the highest-value applications for a handheld imager, and the 256 x 192 resolution of the HT-18+ matters here because panels are usually inspected from an angle and at distance.
Rotating machinery and mechanical maintenance
Bearings, couplings, gearboxes and belt drives all convert developing mechanical faults into friction and therefore into heat. A thermal survey of a conveyor drive train, a pump set or a compressor identifies the specific bearing running hot relative to its identical neighbours – a comparison a single-point thermometer struggles to make reliably because it never captures the whole train at one moment under the same conditions. In mining and bulk materials handling, where an unplanned conveyor stoppage is measured in lost production per hour, this comparative view is the core of the technique.
Building envelope, damp and insulation
Thermal imaging cannot see through a wall, but it reads the surface temperature pattern that conduction produces on the wall face, which is why missing insulation, thermal bridging, hidden pipework, air leakage paths and rising or penetrating damp all become visible. Evaporating moisture cools the surface it sits on, so damp typically appears as a cool region with a distinct boundary rather than a diffuse gradient. Cape Town's wet winters make this a seasonal application: the temperature differential between inside and outside is largest in the same months that damp problems are most active, and a survey done on a cold, still morning before the sun has loaded the facade gives the clearest results.
HVAC, refrigeration and cold chain
Thermography verifies that a system is doing what its design says it should: even coil temperatures, correct refrigerant charge indicated by the evaporator frost line, ducts that are actually delivering conditioned air, and door seals that are actually sealing. In agricultural packhouses and cold stores, a single failing seal or a bridged insulation panel is a continuous energy cost and a product risk, and both show up in a few minutes of scanning where a probe-based survey would take hours.
Discontinued and superseded models
If you are searching for one of the models below, it has been withdrawn from the manufacturer's catalogue. The equivalents Ecotao supplies are noted alongside.
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| Model | Status | What to use instead |
|---|---|---|
| Extech i5 / i7 | Withdrawn from the Extech catalogue | HT-04D or HT-18+ |
| Extech IRC30 / IRC40 | Withdrawn from the Extech catalogue | HT-04D or HT-18+ |
| Extech IRT600 | Marked discontinued by Extech | Extech VIR50 (the manufacturer's stated replacement) |
| Extech IR100 | Withdrawn from the Extech catalogue | Extech IR320 or 42510A |
| Extech 42509 | Marked discontinued by Extech | Extech IR320 or 42512 |
This page previously listed a range of FLIR camera families dated to 2017 – the C-Series, TG165, Ex-Series, Exx-Series, T-Series and T1K. Those listings described product generations that have since been replaced, and the details on them were long out of date. They have been removed in favour of the current, verifiable range above. If you are specifically replacing one of those cameras, contact us with the model and application and we will match it against what is currently available.
Extech infrared thermometers – when a spot reading is enough
Not every temperature problem needs an image. Where the measurement point is known, fixed and repeatedly checked – a bearing housing on a routine round, a flue outlet, an oven set point – a spot infrared thermometer is faster, cheaper and easier to standardise across a team than a camera. These Extech models remain current.
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| Model | Range | Distance to spot | Emissivity | Distinguishing feature |
|---|---|---|---|---|
| Extech IR400 | Up to 332 °C | 8:1 | 0.95 fixed | Compact single-laser unit with backlit display; fixed 0.95 covers most painted and non-metallic surfaces |
| Extech IR320 | Up to 650 °C | 12:1 | 0.10 – 1.00 | IP65 waterproof and rated to a 3 m drop, with programmable high and low alarms and red/blue LED alert |
| Extech 42510A | −50 to 650 °C | 12:1 | Adjustable | 0.1° resolution to 999.9°, audible high/low set points, min/max and data hold |
| Extech 42545 | −50 to 1000 °C | 50:1 | 0.10 – 1.00 | High-temperature model; the 50:1 optics measure small targets from a safe standoff |
| Extech VIR50 | Up to 2200 °C | 50:1 | 0.10 – 1.00 | Built-in VGA camera records each reading as an image or video to microSD; Type-K probe included |
Extech 42510A
Wide-range mini infrared thermometer covering −50 to 650 °C with 0.1° resolution up to 999.9°. Adjustable emissivity, a 12:1 distance-to-target ratio and audible high/low set points make it a practical general-purpose instrument for maintenance rounds.
Extech 42545
High-temperature infrared thermometer reading to 1000 °C with a 50:1 distance-to-target ratio, so small targets can be measured accurately from a safe standoff. Adjustable emissivity and a large backlit display suit furnace, kiln and foundry environments.
Thermal imaging cameras – frequently asked questions
What is the difference between a thermal imaging camera and an infrared thermometer?
An infrared thermometer measures one averaged temperature over a single spot, so you have to already know where the fault is before you point it. A thermal imaging camera measures thousands of points simultaneously and renders them as an image, so it finds the fault for you. A 160 x 120 imager such as the HT-04D takes 19,200 readings at once; a spot thermometer takes one.
Spot thermometers remain the better tool where you need a fast, cheap, repeatable reading at a known checkpoint, or where the temperature is beyond what an imager can handle – which is where instruments like the Extech 42545 at 1000 °C and the Extech VIR50 at 2200 °C earn their place.
What thermal camera resolution do I actually need?
Resolution determines the smallest target you can measure accurately at a given distance. As a working rule, a target should cover at least three by three detector pixels before its reading can be trusted, because anything smaller has its temperature averaged with its background.
A 160 x 120 detector is adequate for distribution boards, motors and building envelopes inspected from a few metres. A 256 x 192 detector such as the HT-18+ is the practical minimum for overhead lines, roof-mounted photovoltaic arrays and any target you cannot walk up to, because its finer instantaneous field of view resolves smaller targets at the same standoff distance.
What does NETD mean on a thermal camera specification?
NETD stands for noise equivalent temperature difference: the smallest temperature difference the detector can distinguish from its own electronic noise. It is quoted in millikelvin and lower is better. A camera rated at 50 mK or better, such as the HT-18+, can separate two surfaces differing by five hundredths of a degree.
NETD matters most on low-contrast work – building envelope surveys, damp tracing, underfloor heating – where the differences you are hunting are fractions of a degree. On electrical work, where a failing connection may run tens of degrees above its neighbours, resolution and temperature range matter far more.
Does Extech still make thermal imaging cameras?
No. Extech no longer lists any thermal imaging camera in its current catalogue. The Industrial Imaging & Inspection category on extech.com now contains only thickness gauges, videoscopes and vibration meters. The former Extech thermal imagers – the i5, i7, IRC30 and IRC40 – have been removed entirely, and the IRT600 thermal condensation scanner is marked discontinued with the Extech VIR50 named as its replacement.
Ecotao supplies the HT-18+ and HT-04D thermal imaging cameras for this application, alongside the Extech infrared instruments that remain current.
What is emissivity and why does it matter?
Emissivity is the efficiency with which a surface radiates infrared energy compared with a perfect black body, expressed from 0 to 1. Most painted, plastic, rubber and oxidised surfaces sit between 0.90 and 0.95 and read accurately at default settings.
Bare and polished metals are the problem. Polished copper busbar can have an emissivity as low as 0.03, meaning it reflects its surroundings far more than it radiates its own heat, and an uncorrected reading will be badly low. The standard workaround is to apply a patch of matt black electrical tape at roughly 0.95 emissivity, let it reach thermal equilibrium, and measure the tape. Both the HT-18+ and HT-04D allow emissivity adjustment from 0.10 to 1.00.
Can a thermal imaging camera see through walls?
No. A thermal camera reads only the surface temperature of the first opaque object in its field of view. What it can do is reveal thermal patterns conducted to that surface, which is why hidden pipework, missing insulation, damp behind plaster and studwork often become visible as temperature differences on the wall face.
It also cannot see through glass. Glass is opaque in the long-wave infrared band and acts as a mirror, reflecting the temperature of whatever is behind the operator – a common source of confusing readings for new users.
Which thermal imaging camera is best for electrical inspection?
For electrical work the HT-18+ is the stronger choice. Its 550 °C upper range covers severely overheating terminations that would saturate a 300 °C instrument. Its 256 x 192 detector resolves individual terminals at a safe standoff outside the arc-flash boundary. And its thermal-to-visual image fusion makes it far easier to identify which specific breaker or phase is affected when the report is read later by someone who was not on site.
The HT-04D is well suited to lower-voltage work, HVAC plant and building diagnostics where the operator can get close to the target.
What is thermal and visual image fusion, and do I need it?
Image fusion overlays visible-light detail onto the thermal image so that edges, labels and component outlines stay legible while temperature data remains visible. Without it, a thermal image of a crowded distribution board is a field of coloured blobs that is difficult to map back to physical hardware.
The HT-18+ blends the two images in 25% steps so the operator can dial in the balance that suits the scene. It matters most for reporting, where the image has to be interpreted by a client or insurer who was never on site.
When is the best time of day to run a building thermal survey?
Early morning before sunrise, or after dark. A thermal survey depends on a temperature differential between inside and outside, and on the building fabric not being loaded with stored solar energy. A facade scanned in the afternoon shows you where the sun has been, not where the insulation is missing.
In the Western Cape, the most productive window for envelope and damp work is a still, cold winter morning – the inside-to-outside differential is at its largest, wind is not stripping heat unevenly off the surface, and damp problems are seasonally active.
Do you deliver thermal imaging cameras outside Cape Town?
Yes. Ecotao is based at 39 Olienhout Avenue, Plattekloof in Cape Town and supplies thermal imaging cameras and infrared instruments throughout South Africa, as well as to Namibia, Botswana, Zimbabwe, Mozambique, Lesotho and Eswatini.
For availability and current lead times, call the head office on +27 21 911 5835 or email sales@ecotao.co.za or aqua@ecotao.co.za.
Need help specifying a thermal imaging camera?
Tell us what you are inspecting, from how far away, and what the hottest thing you expect to see is. Those three answers determine the right instrument.
aqua@ecotao.co.za