Klein HVAC Clamp Meter with Differential Temp

Klein HVAC Clamp Meter
PTR Review
  • Build Quality 8.5
  • Feature Set 9.5
  • Accuracy 8.5
  • Performance 8.5
  • Value 9.0

This is definitely a Pro-level meter that will give you a comprehensive suite of results. It is possible to get higher accuracy, but you'll need to spend several hundred more dollars to get it. 

Overall Score 8.8 (out of 10)

I’m an HVAC Pro in Central Florida, so my phone rings off the hook from April through early October. The heat’s been relentless this summer but on the upside, I’m thankful that it means a lot more work for me. Make hay while the sun is shining, as the saying goes. Today, I’ve set aside my trusted Fluke meter (at least temporarily) so I can put the new Klein HVAC Clamp Meter with Differential Temp to the test. It’s packed full of features, but will I miss my Fluke? I’ve got some overheating customers, so let’s find out!


  • Excellent performance
  • Excellent value
  • Comprehensive set of measurements


  • Jaws are too large for some areas
  • Leads plug into the base and extend overall length


This is definitely a Pro-level meter that will give you a comprehensive suite of results. It is possible to get higher accuracy, but you’ll need to spend several hundred more dollars to get it. 

Klein HVAC Clamp Meter Feature Set

Klein HVAC Clamp Meter

  • Measures AC/DC voltage up to 1000V, 600A AC Current, 60MΩ Resistance, DC millivolts and microamps
  • Automatically ranging True Root Mean Squared (TRMS) measurement technology for accuracy CAT IV 600V, CAT III 1000V, Class 2, Double insulation safety rating
  • Clamp measures AC current and inrush current
  • Two K-Type thermocouple ports for differential temperature measurements
  • Test leads measure AC/DC voltage, DC micro amp, resistance, LoZ, continuity, frequency, duty cycle, capacitance, and diodes
  • Dedicated mode for capturing DC micro amp and inrush current
  • Low-Pass filter and Low impedance (LoZ) mode
  • Dual backlit 6000 LCD display
  • 6.6-foot (2 m) drop protection and a CAT IV 600V Safety Rating
  • Includes carrying case, instruction manual, straight input test leads, two K-type thermocouples, and 3 x AAA batteries
  • Can be used with Magnetic Hanger Cat. No. 69417 (sold separately)
  • Use with K-Type Temperature Pipe Clamp Cat. No. 69140, and K-Type Temperature Probe Cat. No. 69144 (sold separately)


The Klein Tools HVAC Clamp Meter offers more features than most of its peers. You won’t find microfarad measurement and provision for both T1 and T2 K-type thermisters on most meters, but you will on this one. In fact, the Klein gives HVAC Pros comprehensive functionality. My work didn’t require any other instrumentation, and that’s a big advantage. Like other meters, a physical switch prevents you from inserting the leads and the thermisters at the same time.

Klein HVAC Clamp Meter


I like this meter’s overall design but the hard jaws are a bit too big. This jaw size is standard for electricians working with high voltage, but smaller jaws would be optimal for accessing condenser slots and getting into the air handler. Perhaps even a flexible coil version might work better.

Klein HVAC Clamp Meter

Another slight disadvantage is that the test leads plug into the bottom of the meter and extend its total length. I had to unplug the leads each time I put the meter back in its case or I risked damage (at least over time) to the test lead wires as they were bent/wrapped.

Klein HVAC Clamp Meter


How closely does the Klein Tools HVAC Clamp Meter track my Fluke’s measurements? I used the meters simultaneously and, as far as I could tell, the Klein is well within the measurement tolerances. It registers readings similar to my Fluke’s. However, there’s a caveat that I’ll discuss in a moment.

Price & Value

The Klein Tools HVAC Clamp Meter packs in a ton of functionality for $169.50. By contrast, the Fluke meter I’ve been talking about is upward of $700. Is there a big enough difference in performance to choose the Fluke over the Klein? I think a lot of Pros would say “no”. But the Fluke has a level of precision that gives you a big advantage in some circumstances.

Klein HVAC Clamp Meter

For example, let’s say a customer has a dead short somewhere in the house. By measuring the resistance in a wire of the same gauge as the dead short, hitting ground and the wire with the dead short with the leads, and doing some quick math, the Fluke allows me to locate the dead short with near pinpoint accuracy. There’s less precision with the Klein. I could perform the same process with it and be a couple feet away from the dead short. That could make a big difference.

The Bottom Line

Klein’s done a nice job with the Klein Tools HVAC Clamp Meter with Differential Temp. I’d like to see smaller jaws and 90° lead jacks that plug into the face of the meter on the next version but it offers excellent performance at a great price.


Klein Tools HVAC Clamp Meter with Differential Temp Specifications

  • Klein HVAC Clamp MeterItem Number: Klein Tools CL450
  • Material: Plastic/Electronics
  • Batteries: 3 x AAA
  • Auto-Power Off
  • Jaw Size: 2-inch
  • Drop Protection: 6.6 feet
  • Display: 6000 Count LCD
  • Functions: Differential Temperature, Digital Temperature Calibration, DC Micro Amp, Inrush Current, Audible Continuity, Capacitance, Diode Test, Frequency and Duty Cycle, Low-pass Filter, Low Impedance, AC and DC Current, Min/Max, AVG, Data Hold Capability
  • Voltage: 1000V AC; 1000V DC
  • Klein HVAC Clamp MeterFrequency: 999.9kHz
  • Current: 600A AC
  • Capacitance: 6000µF
  • Ohms (Resistance): 60MΩ
  • AC Voltage: 1000
  • Voltage: 1000
  • Polarity Indicator: Y
  • Micro-Amp: 200 μA with 1μA Resolution
  • Temperature Range: -40° to 1832°F (-40° to 1000°C)
  • Standard: CATIV 600V, CATIII 1000V
  • Weight with Batteries: 13.6 ounces
  • Length: 10 inches
  • Height: 1.59 inches
  • Width: 3.77 inches
  • Weight: 12.5 ounces
  • Price: $169.50
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