A multimeter can be an HVAC technician’s best friend. For diagnostics purposes, a multimeter will help you find the exact problem without having to replace random parts, hoping to find the right one.
This article will explain why certified HVAC technicians (and electricians) should always have a multimeter in their tool bag. We will cover how to use a multimeter and show you the best HVAC multimeter, reviewed, and compared just for you.
How HVAC Multimeters Work
The purpose of a multimeter is to test for resistance, current, and voltage of electricity through a circuit, component, or line.
High-end multimeters can also check specific electrical components, like diodes, resistors, short circuits, and continuity.
Depending on what you are checking for the two metal prongs on the device will attach or touch the component on either side of the electrical line (input and output).
Lights, audio alerts, and gauge readouts will then tell you how much electricity is flowing if there is a flow at all, or if the amount of electricity is enough to power the device or part.
Based on these readouts or alerts, you will know if the tested component is working, disrupted, or broken.
From there, you can either replace the worn or broken part or continue testing.
HVAC Multimeters Compared
Choosing a Quality HVAC Multimeter
When you set out to buy the best HVAC multimeter for your specific needs, there are a lot of things to consider. Below is a quick buyer’s guide aimed at helping you find the ideal meter for you.
Multimeter Type Vs. Usage Needs
For the HVAC tech, multimeters are a versatile tool. The truth is, though, they won’t see as much use as other tools like your charging hoses and manifold sets. For this reason, there is such a thing as “too much.”
You will need to consider the use factors versus the need factors. Your meter should be lightweight and easy to use. You won’t need all of the features a professional electrician might need. So focus on the meters that offer you various testing features, the right type of probes, and a display that is easy to read and understand.
Accuracy & Versatility in Measurements and Functionality
Another thing to consider is how accurate you need the meter to be versus how versatile the meter should be. High accuracy is essential, don’t get me wrong. However, most HVAC techs only need to diagnose with their meters. If the resistor is bad, it doesn’t matter how many thousandths of a volt is pushes through.
Likewise, you will need to be able to check for volts, ohms, amps, and current, so ensuring your meter has the basic functionality along with a broader versatility will suit your needs better than a meter that focuses on accuracy instead of being adaptable.
The display count is the number of digits the meter will show on display. The most common for digital displays is measured in counts (2000, 6000, 20000, etc.). The other measurement you will see is digits, always with a half digit (a 1 or blank). A 3 ½ or 4 ½ digit display will show 3 or 4 digits (respectively) and the ½ digit, which is always a 1 or left blank.
Display counts will always start at 0. So, for example, if your meter has a display count of 6000, the maximum number your screen will show is 5999 (the 0 is the 6000th count). The higher the count, the more accurate the reading. The most common digital meters use 4 ½ digits and a minimum of 6000 counts.
Safety & Reliability (Safety Certificates)
Most multimeters will go through a barrage of testing and certification process for safety requirements. Because they deal with electricity, they fall under the watchful eye of many independent testing laboratories. You may find the certification labels such as UL, CE, CSA, etc.
Multimeters need to be protected (and protect you) against current and voltage, arc, over-spikes, and grounding issues. There are 4 primary categories (CAT I, II, III, and IV) to determine which application is best suited for that particular meter.
The higher the category rating, the more protection the meter has against transient spikes and over-voltage. To determine the required CAT number for you, the simple rule is to determine how far you are from the power source.
If you are working at the breaker panel where the power enters the home, for example, a CAT III is required. Inside breakers need a CAT II, and devices connected inside the circuit require a CAT I. For the voltage and amps, most HVAC systems use a CAT II, or III is your best bet.
There are certain features that a multimeter can offer that are nice to have, but not essential. Other features, for the HVAC technician, are crucial. Without listing every possible feature available, let’s focus on the ones you will want to ensure your model has for your HVAC needs.
Temperature Gauge Tester
While a temperature gauge on a multimeter is a rare find, it is an important one when you can locate one. The temperature gauge will help you monitor line temps without the need for using multiple tools.
Bright LED Display
With a digital multimeter, you will have access to the LED display. Some models will offer backlit displays while others have bright LED displays. If you work a lot on systems in low light situations, such as in an attic or crawl space, the LED displays will serve you better. However, any model with a lit display will be better than none at all.
Non-Contact Voltage Detection
NCV, or non-contact voltage, is a method of testing the line for voltage and current without actually having to touch or connect to the wires. This alternative testing method is a quick and easy way to determine if the power has been shut off (or restored) before you open the HVAC panels and begin working.
Auto Shutoff Function
Most digital meters will run on 9-volt batteries. As a result, they will work fine for about 40 to 100 hours. However, you can help extend this battery life by picking a meter with an auto-shutoff function. When the meter is not in use for a predetermined time, the meter will shut off to conserve battery power.
Some meters will retain last readings even through a shutoff, but some will not, so you need to verify which one your chosen meter is capable of.
Price & Warranty
You also need to consider the price and warranty period of the meter. Because you won’t be using the meter at every job or even every day, it isn’t very feasible to spend a lot of money on a meter that you rarely use.
However, you don’t want to opt for the cheapest meter either, as you want your HVAC multimeter to be accurate and offer the features you need when you are required to use it.
The warranty period should cover the meter from damage, normal wear and tear, and craftsmanship. Check the term length and claim requirements before committing to make sure you understand what is and isn’t covered.
7 HVAC Multimeters Reviewed
Now we get to the good part. Let’s take a look at the 7 best HVAC technician multimeters, reviewed, and compared for you.
1. Simpson 260-8P
Best Analog Multimeter
|Battery Life||200 hours|
|Battery Type||9-volt, AA|
If you are looking for the best high-end analog multimeter, you have found it. Our top pick, the Simpson 260-8P is an HVAC tech’s dream. Except for not being able to clamp or measure True RMS, the analog meter is rugged, durable, and built to last.
You won’t receive a carrying case or a protective cover, though, so if your travels take you off the beaten path, you might want to find a way to protect the test equipment from rolling around your truck.
The Simpson unit comes with alligator probes but will accept many aftermarket styles and options. It also comes with the required batteries (AA and 9-volt), which will last up to about 40 hours before needing to be replaced.
If you are a purist, Simpson also offers a wide range of accessories, including clamp probes, banana tips, and external power sources. The color-coded meter is also gauged for AC frequency response and has an overload protector for when you are working directly in the condenser or evaporator units.
- Probes and batteries included
- Many accessories available
- Ideal for any HVAC situation
- Durable enough to go anywhere
- Will require calibration before use.
- Must view needle from straight on
2. Fieldpiece SC260
Best Fieldpiece Multimeter
|Battery Life||Up to 150 hours|
Fieldpiece is a well known and respected brand in the HVAC community. They rival every major manufacturer for many different areas. The SC260 is the best Fieldpiece multimeter available. With a 9-volt battery life of up to 150 hours, this digital clamp and probe meter will serve you well for years to come.
With a resolution of 0.01, measurements in ohms, voltage and amps, you won’t have any trouble finding the fault in the HVAC system. The clamps allow you to work with any electrical component wires while the probes quickly and accurately test your capacitors, resistors, contactors, and diodes.
Unlike the other models in the SC200 series, the SC260 has a backlit LCD panel for quick, simple viewing of the readouts in any lighting condition. The unit is over 9-inches long, though, and it can become cumbersome in tighter spaces. However, with the magnetic hanger 40 mega ohm readings and continuity and diode testing, there isn’t anything this unit can’t do for you.
When measuring temperatures, the initial numbers may be a little high. However, if you move the probes a little or allow them to sit for longer periods, the temps tend to level out. If you find the fault too often, the meter is backed by a 1-year full warranty.
- Carrying case, battery, probes, and temperature gauge included.
- Min/Max and True RMS capable.
- Auto-off preserves battery life.
- May not have the most accurate temp sensor
3. Fluke 116
Best Digital Fluke HVAC Multimeter
|Battery Life||Up to 200 hours|
Fluke is the name that everyone should know when it comes to multimeters. The long-time industry leader brings you the best digital Fluke HVAC multimeter around. This Fluke 116 model is compact and ergonomic. The offset dial allows for single-hand operation and comes with everything you need to open the box and start testing.
You can use this True RMS meter for all things HVAC, and the built-in thermometer will quickly read off temps whenever you need them. If you need a magnetic holder, you can purchase the ToolPAK accessory, with which the 116 is fully compatible.
This unit will test all features of your HVAC equipment and can easily replace a couple of tools in your bag. The right meter will have you diagnosing the problem in minutes instead of hours, and the Fluke 116 can help you pinpoint the problem area faster than most with its slim design and highly visible readouts.
The 116 also comes with a white light LED readout for low-visibility readings. You can breathe easy knowing your investment is protected, too, as all Fluke DMMs come with their 3-year full warranty.
- Low input impedance prevents ghost readings
- min/max/average comes with elapsed time to record feature.
- CAT III rated to 600 volts
- Doesn’t have a clamp for wire readings
4. Fluke 323
Best Clamp Multimeter
|Battery Life||Up to 200 hours|
If you like the Fluke 116 but need a multimeter with a clamp, you are going to love the Fluke 323. This model is everything the 116 is and more. You will find the low input impedance for anti-ghost readings along with the standard 3-year warranty that comes with all Fluke models.
This monster is CAT III rated to 600 volts like the Fluke 116, but it is also CAT IV rated to 300 volts. When you are working on direct equipment and need proper readouts at all times, the Fluke 323 is the model that should be in your tool belt.
With this clamp meter, you can even test conductors without touching through the jaw openings (up to 30 millimeters) and has audible tones for continuity testing. You can store up to 400 recordings and review them at any time. There is also a multitude of features like a one-handed operation that you don’t find in other brands.
One bad thing to take note of, though, is that like most Fluke models in this range, there isn’t a probe wire storage area. You can, of course, keep them in the case, but it does become a pain to have to remove them and wrap them up after each use. Onboard clips or storage rails would help this be the best overall multimeter on the market.
- Low input impedance reduces the chances of ghost readings
- Slim body with offset dial for one-handed operation
- Carrying case holds all included components
- Not compatible with Fluke TookPAK
- Probes have caps but no storage space
5. Crenova MS8233D
Best Cheap HVAC Multimeter
|Battery Life||Up to 60 hours|
If you are looking for a second meter or are just starting out and need a quick, reliable multimeter to get you going, the Crenova MS8233D is the ideal model for you. This is the best cheap HVAC multimeter in the industry and has everything you need for most HVAC jobs.
Of course you will be without some features and options that higher-end models have standard equipped, but for the most part, you won’t miss out on much. The value to cost ratio is quite high with this particular model.
At 2000 counts, the LCD display isn’t the best, but it is enough for most HVAC needs. You also get audible alerts for continuity, and it comes with both pin and alligator clip probes. The flip-out stand gives you hands-free viewing of the backlit display, and for the money, the accuracy is highly reliable.
There isn’t a clamp accessory, so conductor and wiring testing is out. However, for diagnosing an evaporator unit, heater, or capacitors, you won’t find a better deal on a reliable meter anywhere. The auto-range meter will have you dialed in without second-guessing if you have the dial right. Just pick the testing component, attach the leads, and begin probing your components.
- Auto-range meter helps learn how to use more advanced multimeters
- Double-fused overload protection
- Kickstand and high-vis display offer hands-free operation
- ABS and plastic aren’t the most rugged build materials
- 2000 count display may not meet all needs
6. Amprobe AM-510
Best Multimeter For Home Use
|Battery Life||Up to 100 hours|
If you are a DIYer, you will want a good multimeter for around the home. Amprobe has you covered. The AM-510 is the best multimeter for home use, but there is more. They have a wide range of models to choose from, each with a purpose for various applications. While all of the meters will perform the needed tests, the other models, such as the AM-520 is geared towards the HVAC DIYer.
For the HVAC Pro, the AM-560 adds better temperature readings and more accurate settings for precision control. You can also opt for the AM-570, which is basically the 560 model bundled with extra probes and clips.
Around the home or in light-duty settings, though, the AM-510 is ideal for beginners, DIYers, and those looking for accurate readings without all the fancy extras and the higher price tags. While you won’t get wattage here, you can use the readouts on the display to do the math yourself (Watts = voltage x amps).
The built-in flashlight and kickstand flip-out also help you get your probes in the right spot, hands-free, regardless of lighting conditions. If you are worried about your investment, the 1-yer warranty should help you relax a bit.
Everything is covered except for the battery, and claims are relatively simple and straightforward to make. The one downside to this model is that the Non-Contact Voltage readings are there but don’t always work.
While it is more hit or miss, this is a common feature with NCV models without a clamp. As long as you don’t expect too much and don’t need to use this for daily, heavy use, you will be satisfied with this purchase.
- High-quality fuses for overload protection (ceramic)
- Rugged casing and rubber cover for added protection.
- Built-in flashlight helps in low-light working conditions
- NVC may not work at all times
- Probes can be touchy if the rod ends are bent
7. UEi Test Instruments DL369
Best Beginner Multimeter
|Battery Life||40 hours|
If you are training for HVAC certification, have just entered the career field o are looking to start, the best thing you can do is find a reliable multimeter to have in your pocket to learn on and grow with. The UEi Test Instruments DL369 is that multimeter.
While it isn’t designed for the professional in mind, this model is higher quality than a DIY model you’ll find at a department store. Let’s cover the bad news first.
If you are using the DL369 for capacitance and resistance, the readouts will be extremely slow. Some reports that it takes so long to get the readings they have shut the device off, thinking the batteries were dead.
Second on the bad list, you don’t get any temperature readings. Aside form these two things, though, for a beginner, this is the best model you can use. While it won’t give you the complete accuracy of a Fluke or Fieldpiece, you will be close enough for diagnostic work.
The easy to use interface and the high-vis display will help you find the fault in the system and let you know where you need to focus your repair abilities. Meanwhile, you will grow familiar with using a multimeter and decide from there which upgrade model you want to pursue.
- All the basic features you need when starting out
- Ideal model to learn with
- Rugged design with one-handed operation
- No temperature readings
- Capacitance readouts are extremely slow to produce.
Types of Multimeter
There are two standard types of multimeter, analog and digital. The digital versions have sub-types, including clamp and auto-ranging. Let me briefly explain their differences and benefits to you.
Analog meters are the original meter. They usually have a single twist knob to select the type of testing you need to do (volts, amps, ohms, etc.) and an analog needle gauge that displays the results.
Analog meters are among the types that don’t require a power source like a battery and will never fail. However, they can be challenging to read as the printing on the needle display is small print. In low-light conditions, you may not be able to see the gauge at all.
While analog multimeters have their place (and are notably less expensive), they have fallen out of fashion for the more advanced digital multimeter options.
Digital meters will have a digital display, usually an LCD or LED readout, instead of a needle gauge. The readouts are much more accurate as they can test currents and voltage to tenths (or even hundredths).
You will also appreciate that most displays are backlit so you can read them in any light conditions or from a distance. Like analog meters, they will have visual and audible alerts to let you test things like continuity.
Aside from the standard digital multimeter, you may also want to invest in a clamp meter. These are specially designed meters with a clamp or “claw” that wraps around power lines, cords, etc. to test for current in the line. Instead of probes like a digital meter, clamp meters are better suited for testing high-voltage and to ensure the 220v line is powered off before you start working.
Some clamp meters also have robe ends to test current and amps. However, for the most part, these testing aspects are more general and less accurate than a standard digital multimeter.
When you are testing for a specific range, you will need to turn the dial or make your digital selections for a set range to test within. Unless your multimeter is an auto-ranging meter. These meters are a little more expensive but require less set up on your part.
Based on the test you are performing, and which ports you have the probes connected to, the auto-ranging meters will select the best, or optimal, range for the readouts.
How to Use a Multimeter
Multimeters are simple tools with a lot of settings. It is these settings that make them daunting to learn how to use. Once you know what you are looking at, how to configure the meter, and how to read it, it will quickly become second nature.
Configuring a Multimeter
Each of the three primary settings (amps, volts, and ohms) will have a series of various ranges to choose from. You will want to select the setting that offers a high enough reading to measure the expected output, but low enough to get an accurate reading.
For example, if you are testing the voltage of a 9-volt battery, you can set the meter to read anything over 9 volts. If you set the meter to 200 volts, there will be no reading at all because 9 is too low for the set range. If you set the meter for 20 volts, you will get an accurate reading of the battery’s output.
One thing to keep in mind is that as long as the black probe is connected to the COMM port and your red probe is connected to the correct amps or volts/ohms ports; it doesn’t matter which side you touch the probes to. The one exception is with diodes, which are one-way devices. Connecting the diode backward can give you a 0 reading, which may be incorrect.
Reading a Multimeter
When reading the meter, you will need to know if you are dealing with direct current (DC) or alternating current (AC).
The symbols on the meter will tell you which one you are dealing with. A solid or dotted line refers to DC, while a wavy line means AC.
You also want to watch the display. In continuity checks, a 1 means no flow, while all zeros imply continuity.
Likewise, an “OL” reading means overload, and there is either something wrong with the component, or your settings are too low for the load.
Each model will come with an owner’s manual that will explain their specific symbols and meanings.
While most are fairly universal, the actual symbols used can vary somewhat and may be confusing if you switch to a different brand or model.
Frequently Asked Questions
What do the symbols mean on a multimeter?
The symbols will tell you if the meter is reading AC or DC current, and whether the readout is in ohms, volts or amps. There are also symbols for continuity (resembles a sideways WiFi symbol), and diode checks. If your meter has other symbols, the owner’s manual will explain what they are and how to read them.
What is the difference between min/max and peak modes on the multimeter?
When you set the multimeter to min/max mode, it will display the readings in two numbers that cover the duration of the time you had the probes connected. The lowest reading and highest reading will be displayed. When in peak mode setting, the readings will show the positive and negative peak of the voltage readout.
Can I measure AC voltage?
You can use a multimeter to test AC voltage, but it isn’t advised. AC voltage, such as that which runs through your home’s outlets, can be unpredictable. Depending on the load and the peak-to-peak measurements, if you touch the probes incorrectly or to the wrong items, your multimeter can get fried, and you can get jolted.
How many readings can be saved in the memory of the meter?
This will depend on the quality of your multimeter. Some cheap meters won’t store any values, while high-end models like Fluke can store over 400 readings.
What if I intend to measure a large current with the multimeter?
As long as your meter can handle the current, you will only need to switch the red probe to the port marked as 10A. You will also need to ensure your voltage setting is high enough to read properly as well.
Can I use a multimeter for all HVAC work?
For all electrical HVAC work, you can get a high-quality meter that will handle the currents and amps needed for every aspect. You will need a multimeter that has probes and a clamp, and it should be rated at least as a CAT III.
Is it safe to use the multimeter?
Multimeter use is safe. It doesn’t require any special protective equipment (though electricians gloves may be a wise investment). Overall you need a good knowledge of the meter settings and what to test. Common sense will carry you a long way when dealing with electricity and multimeters.
Which one should I choose between digital and analog multimeter?
Analog meters are redundant now. Digital multimeters are much more accurate, don’t require a specific viewing angle, and offer better readouts, vision, and resolution. With the digital meters, you can also perform more functions and tests than analog meters offer.
How do I test a capacitor with a digital multimeter?
If your digital multimeter has the ability to test a capacitor, it will have a capacitor setting. Once you have the capacitor out of the condenser unit and it is sufficiently drained (you will need to discharge the capacitor by grounding out the common/fan and common/herm terminals), you can test it.
First, you need to see what the microfarad rating is. This will be a double-digit number (30, 40, 35, etc.) in most cases (though there are 5 mF capacitors) and a +/- 5 or 0 written on the label. The plus or minus is the percentage of fault built-in and is usually 5. Connect the ground (black) probe to the common lead and touch the red probe to the fan lead.
Your digital display should read 5.0 (with a 5% buffer). Connect the red probe to the herm lead, and you should get a reading within 5% of the total mF rating. So, if your capacitor is a 45 – 5, the fan reading should be between 4.5 and 5.5, and the herm reading should be between 44.90 and 45.10. If the reading is not within those specs, the capacitor is bad.
Choosing the right multimeter for your HVAC tech needs doesn’t need to be a difficult decision. A digital or analog multimeter with the right features and options for your everyday use is ideal. As long as you can stay within your budget and get a quality and durable meter, you will be just fine.
If you don’t know which one to pick, we suggest the Simpson 260-8P 12391 model. It is a high-end meter and costs a little more than some others, but it will give you every setting and perform every test you will need in your HVAC tech career.
- 220v vs 110v Air Conditioners (Compare Cooling & Costs) - July 10, 2021
- Fan Vs AC (Compare Cost, Cooling & Efficiency for Homeowners) - July 8, 2021
- Single Stage Vs Two Stage Air Conditioner (AC Comparison) - July 8, 2021