Best Digital Manometer to Measure Gas Pressure Gauge

A digital manometer is a device capable of measuring and/or displaying the pressure level of air or any other kind of gas. Industrial-grade digital gas pressure meters are some vital tools used by HVAC service professionals to measure the pressure of a wide range of gases within the air conditioning systems of commercial, industrial, and residential buildings. There are several digital manometer types in use today that are suitable for solving various problems encountered by both DIYers and industry professionals.

While electronic manometer is available in many different styles, they all utilize similar operation principles and offer some advantages over standard manometers. It’s important to note that regardless of their design, digital manometers never actually measure the volume of gas. Instead, they make estimates based on pressure readings, which is why we measure pressure instead.

Best Digital Manometer Reviews

1. Hti-Xintai Store Digital Manometer, Dual Port Air Pressure

Digital Manometer, Dual Port Air Pressure Meter Pressure Gauge HVAC Gas Tester, Differential Pressure Manometer with 5/16 Inches Diameter Pressure Port, Hti-Xintai
  • Low Range/High-Resolution Gauge or Differential Pressure.
  • Measuring Ranges: ±13.79 kPa / ±2 psi / ±55.4 H2O.
  • High Accuracy: 0.001psi.
  • 11 Selectable Units of measure: inH2O, psi, bar, mbar, kPa, inHg, mmHg, ozin2,FtH2O, cmH2O, kgcm2.
  • Large LCD with backlight.
  • MAX/MIN/AVG values and Zero function.
  • Data Hold and Auto power off functions
  • Error Codes for out of range indication.
  • Low Battery Indication.

The Ht-1890 HVAC Digital Manometer is a professional gas manometer to measure gauge and differential pressure in the range of ±2 psi. It has featured Zero function for offset correction or measurement. It is ideal for carrying out servicing and troubleshooting on air conditioning and refrigeration systems. Measure draft, gas supply, manifold, or burner pressures. Dual input offers users the ability to measure pressure drops across heat exchangers, cooling coils, supply, and return registers, and filters.

Updated with 5/16″ Pressure Port Size

Fit in most gas valves and you do not need to purchase additional accessories. Flexible black silicone tubing size updated to 19” length *1/4” diameter.

Differential Pressure Manometers



Specifically for use in HVAC, pneumatic controls, medical equipment, gas appliance repair and installation, laboratory testing, computer peripherals.

One Set Included
  • 1x Manometer
  • 2x Flexible transparent silicone tubing: 19” length 1/4” diameter
  • 1x 5/16″ Barbed gas valve fitting
  • 1x Soft Pouch
  • 1x Instruction Manual
  • 1x 9V Battery

2. Testo 510 Digital Manometer

testo 510 Digital Manometer I Dual-Port Differential Pressure Meter for air Conditioning Systems and Ventilation ducts


  • Dimensions: 5 x 2 x 1 in. / 119 x 46 x 25 mm
  • Operating temperature: 32.0° to 122.0 °F / 0 to +50 °C
  • Protection class: IP40
  • Maximal static pressure: 7.252 psi / 500 mbar
  • Measuring rate: 0.5 sec
  • Battery type: 2 AAA batteries
  • Battery life: 50 h (average, without display illumination)
  • Storage temperature: -40.0° to 158.0 °F / -40 to +70 °C

Testo was founded in Lenzkirch, in the Black Forest region of Germany, in 1957 and has since designed, developed, and manufactured portable test and measurement instrumentation and solutions. Backed by 60 years of measuring engineering experience, testo’s mission is to provide the highest quality, service, and value.

Testo’s first product manufactured was a simple electronic thermometer. Today, the product line has expanded to include a large variety of temperature measuring instruments, such as data loggers, air velocity meters, humidity and dew point meters, refrigeration service analyzers, multifunction instruments, stack gas analyzers and air emission monitors, water analyzers, tachometers, sound, pressure, and light meters, and thermal imagers.

Quickly and accurately measure differential pressures on air conditioning systems and ventilation ducts with the testo 510 digital manometer. The testo 510 can measure total external static pressure, differential pressure, duct velocities, manifold pressures, along with airflow with the addition of an optional pitot tube.

Lightweight and Convenient

At only 3oz. (90g) including the protective cap and batteries, the pocket-sized testo 510 electronic manometers can be taken to any job site. The bright, backlit display allows for easy viewing in any environment, while the magnets on the rear allow for hands-free readings.

Diverse Range of Units

The compact testo 510 is suitable for any different pressure job with the option of 10 different units of measurement: hPa, mbar, Pa, mmH2O, inH₂O, inHg, mmHg, psi, m/s, fpm

3. UEi Test Instruments EM152 Dual Differential Digital Manometer

UEi Test Instruments - Electronic Manometer (EM152)

The EM152 measures differential, positive or negative pressure. Units can be selected from any one of 11 options including; inH2O, psi, bar, mBar, kPa, InHg, mmHg, ozin, FtH2O, cmH2O and kgcm. Features pressure zero, hold and record. A simple hose barb allows for quick tubing connections and is backed by a 1-Year limited warranty.

From Manufacture

UEi Test Instruments has over 50 years’ experience designing and manufacturing a broad range of award-winning, industry-leading Test and Measurement Tools. Professionals recognize the UEi brand for quality and innovative features designed to solve real-world problems. UEi backs its products with dedicated technical support, service, and repair teams.


  • Dual input differential in 11 scales
  • Hold/Min/Max/Avg
  • Record with elapsed time stamp
  • Pressure zero
  • Backlit display
  • Relative time clock
  • Low battery indicator
  • Auto power off
  • Magnetic mount


  • Validate pressures in accordance with equipment manufacturer’s specification for optimal system efficency and safety. M
  • easure draft, gas supply, manifold or burner pressures
  • Validate pressures in accordance with equipment manufacturer’s specification for optimal system efficiency and safety. registers and filters

4. TEKCOPLUS Digital Handheld Manometer HVAC Air Vacuum

Digital Handheld Manometer HVAC Air Vacuum/Gas differential Pressure Gauge Meter tester 11 Units with Backlight, ±13.78kPa ±2PSI, 1-2 Pipes Ventilation Air Condition System Measurement

Technical Specifiations

  • Pressure Range: ±2psi
  • Accuracy: ±0.3% FSO (at 25°C)
  • Repeatability: ±0.2% (Max±0.5%FSO)
  • Linearity/Hysteresis: ±0.29% FSO
  • Response Time: 0.5 Seconds
  • Over Range Display Indicator: Hi
  • Under Range Display Indicator: Lo
  • Operating Conditions: 0 – 50°C(32 – 122°F)
  • Storage Conditions: -10 – 60°C (14 – 140°F)

Measures air pressure of the single pipe or differential pressure.HVAC/R refrigeration air-conditioning industry is used to measure the pressure. Measure negative pressure setting to ensure indoor air pests will not pollute the air in the outside world.

This Manometer can measure the air pressure of the single pipe or differential pressure of two is suitable for measuring ventilation and air condition systems and is widely used for gas measurement, calibration, and troubleshooting of any gas pressure system.

Power Press Power on/off button to turn power on or off.

The meter will auto power off in 10 minutes without any operation. Press the HOLD button and Power on/off button together to open the meter, the Power symbol will appear

Data Hold Function.

Press the HOLD button to freeze the reading momentarily. Press the HOLD button again to return to the normal operation.

Record Function

When turning on the instrument, it is already starting to record the MAX/MIN/AVG reading. Press the REC button to display the Max reading, Min reading, AVG reading, and return to the normal measurement.

Over Range

HI symbol will appear on the display when the pressure value is over the Max range LO symbol will appear on the display when the pressure value is below the Min range.


Hold on REC and DIF buttons together and then press the Power on/off button to open the meter, it will enter the calibration method directly:

a. Zero adjusts Press REC and DIF at the same time, the reading will be -00.00.

b. Data adjust After adjusting Zero, input a standard pressure (kPa), and then adjust the reading the same as the standard pressure value.

Set Includes:

  • 1 x Digital Manometer
  • 2 x Plastic Hose
  • 1 x Metal Connector
  • 1 x Carry Pouch
  • 1 x 9V battery
  • English Manual

5. General Tools DM8215 Deluxe Digital Manometer

General Tools DM8215 Deluxe Digital Manometer, 0-15 psi

The #DM8215 is optimized for applications in which gage or differential pressure ranges from 0 to 15 psi. Its resolution of 0.01 psi is sufficient for measuring gas pressure in HVAC/R systems with ±0.3% accuracy. Ingenuity is the core of what makes General special.

Digital Manometer provides select psi, inH2O, bar, mmHg, ozin2, kgcm2, kPa, ftH2O, inHg, cmH2O & mbar. This digital manometer has a digital display gauge or differential pressure. Suitable for gas or water.

  • Measurement range/resolution: 0 to 15 psi/0.01 psi
  • Display unit options: psi, in.H2O, bar, mmHg, oz.in2, kgcm2, kPa, ft.H2O, in.Hg, cmH2O, mbar
  • Min/Max memory + data hold
  • Large backlit dual-readout LCD that displays the measured pressure above a relative time clock (which enables resetting of the measurement timeline)
  • One-button relative zero setting
  • Includes two connection hoses
  • Optional #ASFTKIT PC data logging software/hardware is available
  • Auto power off (can be disabled for data logging)
  • NIST calibration is available

How to Use Manometer

A manometer is used to measure the pressure difference between two gases, often the atmosphere and the gas being tested. A typical manometer consists of a U-shaped tube filled with either mercury or liquid. The long sides of the tube have a measuring scale marked off in millimeters. When a gas line is connected to one side of the manometer it shifts and the difference in the height of the liquid in each side is used to calculate the pressure of the gas line. The formula for calculating the pressure is pd = ρ g h, where PD = the pressure difference, ρ = the density of the liquid in the manometer; mercury equals 13,590 kg/m3; water equals 1,000 kg/m3, g = acceleration of gravity, 9.81 m/s2 and h = the height of the liquid in meters.

Using manometers for measuring pressure:

A U-tube manometer is the simplest pressure measurement device. Its name comes from the U-shape formed when the two ends of a flexible tube full of liquid are raised to keep the liquid from coming out of the ends. A U-tube manometer is a ‘liquid’ balance. 

A spring balance used in the kitchen weighs a load by matching the force produced by the weight of the load with the force produced from the tension of the balance spring. The change in length of the spring is a measure of the load’s weight and is shown on a graduated scale by a pointer attached to the spring. Similarly, a U- tube manometer is used to balance the weight of the liquid in one leg of the ‘U’ against the pressure introduced into the other leg. The difference in height between the two legs of liquid represents the pressure pushing the liquid down one leg and up the other. The height difference is measured on a graduated scale.

Pressure in a Column of Liquid or Gas

The invention of the U-tube manometer allowed the early investigators into fluid mechanics to confirm that pressure was directly related to the sum total of the forces acting on a surface. If you were to stand on the seashore, the pressure on you would be the weight of the air column directly above you. That pressure has been given the name of ‘one atmosphere’. If you were to dive to a depth of 10 meters (about 32 feet) there would now be an added pressure on you of the weight of water above plus the weight of the air column. 

By international agreement (a convention) ‘absolute’ pressure includes the pressure of the column of air whereas ‘gauge’ pressure does not. Gauge pressure is the pressure showing on a pressure indicator dial and is one atmosphere less than absolute pressure. 

The pressure of 1-m depth of water is found from the formula – 

Pressure = Density x Gravity x Height of liquid column P=ρgh 

The unit is a Pascal. Gravity has a value of 9.8 m/sec2 at sea level. For simplicity of multiplication, the value 10 m/sec2 will be used. The density for water is 1,000 kg per cubic meter at 20 oC. 

Putting all the know values back into the pressure equation gives – 

P=ρgh=1000kg/m3 x10m/sec2 x1m = 10,000 Pa = 10 kPa 

The calculation shows that 1-meter of water is equal to about 10 kPa, which means 30 meters of water produces a pressure of nearly 300 kPa. One atmosphere of air pressure at sea level is 101 kPa. This means the pressure at 30 meters depth below sea level is 300 kPa gauge pressure or about 400 kPa absolute pressure. The same formula can be used to calculate negative, or vacuum, pressures.

 Figure No. 1 U-tube Manometers with Water and Mercury

How to Use a U-tube Manometer 

Figure No. 1 shows three manometers open to the atmosphere. The left one has the same pressure in both legs and the liquid levels are the same on both sides. The U-tube in the center shows a pressure applied to the left leg of 100 kPa. The water level in the left leg has gone down and the level in the right leg has gone up. The difference in the height of water between the two legs is 10 meters. Since the liquid is water, each meter height represents 10 kPa and a 10-meter high water column represents 100 kPa gauge pressure. The remaining U-tube shows a pressure of 100 kPa as well but this time mercury is used in the tube. The height of mercury is now 750mm. The density of mercury is 13.6 times that of water. Because mercury is so much heavier than water the same pressure raises a correspondingly lower column of liquid. 

If a manometer were used to measure a vacuum the column of liquid would be drawn up toward the vacuum and the difference in the height of liquid between the two legs would be a measure of the vacuum pressure below atmospheric pressure. 

Making a U-tube Manometer

To make a U-tube manometer requires a clear plastic tube mounted in the shape of a ‘U’ onto a board marked with a graduated scale. The pressure to be measured determines the selection of the liquid used in the tube. The U-tube liquid’s density and the pressure being measured determine the height of the liquid column and the corresponding height of the backing board. 

Mike Sondalini – Maintenance Engineer. 

We (Accendo Reliability) published this article with the kind permission of Feed Forward Publishing, a subsidiary of

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