Best clamp meter for HVAC service calls

The furnace quits on the coldest morning, the condenser has a suspect capacitor, and your next call is already waiting. Buy the clamp meter that covers those jobs—not the one with the biggest amp number on the box.

Start with Fluke 902 FC for a compact HVAC function set. Choose Fieldpiece SC680 when Job Link, dual temperatures and compressor inrush belong in your daily routine. Klein CL390 is the useful non-wireless alternative. The two general-purpose Flukes below have a different job.

Quick picks for the service bag

• Best for HVAC service: Fluke 902 FC. DC microamps for flame-sensor work, capacitance, a temperature probe and Fluke Connect in one meter.
• Best wireless Job Link pick: Fieldpiece SC680. Dedicated inrush, dual temperature and electrical readings sent into the Fieldpiece app.
• Best electrician crossover: Fluke 325. AC/DC clamp current plus temperature and capacitance for a mixed electrical workload.
• Best budget Fluke clamp: Fluke 323. The lower maker-priced Fluke here for basic current and voltage checks; keep separate flame-sensor, capacitor and temperature tools in the bag.
• Best non-wireless HVAC option: Klein CL390. DC microamps, capacitance and a thermocouple with a reverse-contrast display.

Use a meter with the right CAT rating for the work and follow your lockout procedures.

The features that change an HVAC buying decision

DC microamps is the furnace feature. Look for a dedicated µA DC function through the leads, rather than assuming an AC/DC clamp can read a flame-sensor circuit. Capacitance covers the capacitor measurement; a thermocouple adds contact temperature. Dedicated inrush captures motor starting current—ordinary hold or min/max is a different function.

Meter	True-RMS	DC microamps through leads	Capacitance	Temperature	Dedicated inrush / wireless
Fluke 902 FC	Yes	200 µA range	To 1,000 µF	Included Type K probe	Not listed / Fluke Connect
Fieldpiece SC680	Yes	1,000 µA range	To 10 mF	Two Type K probes, dual temperature	Yes / Job Link
Fluke 325	Yes	No DC µA range in specifications	To 1,000 µF	Included Type K probe	Not listed / no app listed
Klein CL390	Yes	200 µA range	To 4,000 µF	Included Type K probe	Not listed / no app listed
Fluke 323	Yes	No DC current function	Not included	Not included	Not listed / no app listed

Function sources: Fluke 902 FC, SC680 manual, Fluke 325, Klein CL390 and Fluke 323. “Not listed” means the reviewed specifications do not advertise that dedicated mode.

Fluke 902 FC: the HVAC starting point

The 902 FC puts the furnace and condenser functions together: DC microamps, capacitance and contact temperature, with true-RMS AC measurements. Its clamp reads AC current to 600 A; the small DC microamp function uses the leads. That distinction matters more than another few hundred amps of headline capacity.

Fluke Connect sends measurements to a phone or tablet, supports live trends and cloud storage, and lets you share measurement reports by email. The meter carries CAT III 600 V / CAT IV 300 V ratings. Pick it when you want that compact HVAC mix and already prefer the Fluke reporting workflow (902 FC features and specifications).

Fieldpiece SC680: the connected HVAC workhorse

Choose SC680 for a bag already built around Job Link. The swivel clamp, dual display, magnetic mounting and two Type K inputs suit the tech moving between equipment and the phone. Dedicated inrush captures compressor starting draw; true-RMS and a low-pass filter serve VFD work. Its clamp measures AC/DC current to 600 A.

Measurements go directly to the Job Link app, so you can view the meter reading on the phone. Its published safety ratings are CAT IV 600 V / CAT III 1,000 V. For this shortlist, SC680 gets the nod when inrush and dual-temperature work make the extra functions useful every week (Fieldpiece’s SC680 overview).

Fluke 325: the electrician crossover

The 325 adds DC clamp current to 400 A alongside AC current, plus a supplied thermocouple and capacitance measurement. That makes it a useful crossover for a contractor whose calls mix electrical troubleshooting with temperature and capacitor checks.

Its CAT III 600 V / CAT IV 300 V rating matches the two other Flukes here. The published functions do not include a lead-based DC microamp range, so keep the flame-sensor meter in the bag. Choose the 325 for its general AC/DC clamp work, rather than buying it as a one-tool furnace solution (Fluke 325 specifications).

Klein CL390: the non-wireless HVAC shortlist

CL390 brings the useful trio—DC microamps, capacitance and a K-type temperature probe—without an app workflow. Its reverse-contrast screen, side lead holder and optional magnetic hanger suit a tech who wants to read the meter, write the finding and move on.

Klein specifies 400 A AC/DC through the clamp, CAT III 600 V, max/min and data hold. Pick it for that published function mix; the 600 V maximum alone does not give it the Flukes’ CAT IV rating (CL390 features and specifications).

Fluke 323: the budget Fluke, not the whole HVAC bag

The 323 is the basic AC clamp here: current, voltage, resistance and continuity. Choose it as the simpler companion when your existing tools already cover flame sensors, capacitors and temperature. Fluke’s specification table leaves capacitance, temperature and DC current out; this is a different purchase from the HVAC-focused 902 FC.

The budget label is scoped to our Fluke shortlist. Maker-listed prices checked 2026-10-23 were $207.99 for Fluke 323 and $437.99 for Fluke 325, before promotional codes. That supports the lower-priced Fluke choice, not a claim that it is the cheapest meter across brands.

Turn the reading into a useful job record

A reading gets more useful when the next tech can find it. Save the unit identifier, measurement and units, operating condition, finding and next action together. For example: “Upstairs furnace — flame-signal reading attached — compare with this unit’s service specification.” Keep the maker report or a clear display photo alongside that note.

With a wireless meter, capture the reading in its maker app first, then save a report or image on the device you use for the job. With the other picks, use a display photo and written note. The handoff below uses saved files; the meter apps do not automatically populate Jobber or Housecall Pro.

Jobber: keep the finding with the job or quote

Use Jobber to keep the diagnosis attached to the job: save the reading and the finding before they become two unrelated photos.

In the mobile job or quote, open Notes → Add note, write the finding and use the attachment icon to add the saved image. Notes are internal by default. When emailing a quote, select the attachments you want the customer to receive in Send → Send by email (Jobber notes and attachments help).

Want the reading, repair scope and follow-up together? Visit Jobber.

HCP alternative: attach the file, then share it

Open the job or estimate’s Attachments and upload the saved file. Select the relevant attachments when sending the estimate or invoice. On mobile, select the attachments and use Email or Text → Share; the customer receives a link. Emailed attachments stay separate from the emailed invoice PDF (HCP attachment help).

Round out the service bag

Start with 902 FC for the HVAC essentials, SC680 for the connected Fieldpiece workflow or CL390 for the non-wireless function set. Give 325 the crossover electrical work and 323 the basic AC-clamp role.

Pair the meter with our thermal camera picks, digital HVAC manifold guide and rechargeable work lights. The goal is a service bag that helps you find the problem and a job record that keeps the next visit moving.

Building the full service bag? Compare our A2L-ready refrigerant leak detectors for the calls where the next job is finding the leaking fitting.

Give the meter a reachable home: our HVAC tool-backpack picks compare dedicated meter pockets, device bays and the bag’s weight before you add tools.

Working on the heating side? Choose a combustion analyzer for furnace and boiler tune-ups, then save its report with the service record.

Locating the circuit comes first: our circuit breaker finder picks cover live-outlet tracing and the panel photo to keep with the job.

For sticky rooms and sweating ducts, use our HVAC digital psychrometer guide to choose a humidity probe, handheld or paired supply/return setup.

For motor-winding leakage checks, use our HVAC insulation-tester guide: selectable DC test voltages, a compressor-to-ground checklist and a reading record to save with the job.