Milimetre of water column (mmH2O) - Pressure Unit - Definition, Application, Conversions

What is a millimetre of water column (mmH2O)?

A millimetre water column is a unit of pressure that measures the force exerted by a column of water one millimetre high per unit area at a temperature of 4°C and normal gravitational acceleration. It is the traditional unit of pressure measurement in the metric system and is mainly used for low pressures. The designation of the millimetre water column pressure unit is mmH2O.

Millimetre water column is rarely used in the context of industrial hoses. This unit is more common in low-pressure measurements, such as in ventilation or air conditioning systems. Working pressures in industrial hoses are typically expressed in higher units like kPa or bar.

When is a millimetre water column used to measure pressure?

The millimetre water column is used for pressure measurements primarily when the pressure is low and the accuracy of the measurement is important. Here are the most common applications of this unit:

• Engineering and ventilation technology - In engineering, especially in ventilation and air-conditioning systems, mmH2O is used to measure low pressure in air ducts. This is crucial for ensuring proper airflow and maintaining comfortable indoor conditions. 
• Medicine - Lung and airway pressures are often measured using mmH2O (e.g. during pulmonary function tests). The unit is also used to monitor intracranial and intraocular pressure, which is important in the diagnosis and treatment of various conditions. 
• Scientific research - In scientific research, especially in physics and environmental engineering, mmH2O is used for experiments requiring accurate low-pressure measurements (e.g. in water and air flow studies). 
• Hydrology - The mmH2O unit can be used to measure water levels and hydrostatic pressure, particularly in small bodies of water or in studies related to soil moisture. 
• HVAC (Heating, Ventilation, and Air Conditioning) industry - In the HVAC industry, mmH2O is used to measure differential pressure in heating, ventilation and air conditioning systems, which is crucial for energy efficiency and comfort.

How to measure pressure in millimeters of water?

To measure pressure in millimeters of water (mmH2O), you need the right measuring equipment, such as a liquid manometer, which measures pressure in units of water column, or a digital manometer with the option to select mmH2O units.

Here are the steps to take to measure pressure in millimeters of water (mmH2O):

1. Choose the right manometer - The simplest device for measuring in millimeters of water column is a liquid manometer, which measures pressure based on the difference in water column heights. It can be configured to measure in mmH2O. An alternative is digital manometers, which offer the option to select different units, including mmH2O.
2. Identify the measuring point - Determine where you want to measure the pressure (e.g. in a plumbing, ventilation, or other installation where you want to check the pressure of a liquid or gas).
3. Connect the manometer - If you have a liquid manometer, make sure it is vertical and properly connected to the system. The water column will then react to the pressure, causing a difference in height. In contrast, connect a digital manometer to the measuring point and make sure the connection is tight.
4. Read the result - In a liquid manometer, the height of the water column in millimeters directly corresponds to the pressure value in mmH2O. In a digital manometer, the pressure reading will appear directly on the display in mmH2O units (if available for selection).

If your device measures in other pressure units, you can convert them to millimeters of water column (mmH2O) using the appropriate pressure converters.

Conversion of pressure unit millimetre of water column (mmH2O)

• 1 mmH2O = 0,0001 bar
• 1 mmH2O = 9,80665 Pa
• 1 mmH2O = 0,0980665 hPa
• 1 mmH2O = 0,00980665 kPa
• 1 mmH2O = 0,00000980665 MPa
• 1 mmH2O = 0,000096784 atm
• 1 mmH2O = 0,00142233 PSI
• 1 mmH2O = 0,0393701 inH2O
• 1 mmH2O = 0,0735559 Tr
• 1 mmH2O = 0,0735559 mmHg
• 1 mmH2O = 0,0028959 inHg
• 1 mmH2O = 0,204816 PSF
• 1 mmH2O = 0,0001 at
  

1 millimetre of water column (mmH2O) = 0,0001 bar = 9,80665 Pa = 0,0980665 hPa = 0,00980665 kPa = 0,00000980665 MPa = 0,000096784 atm = 0,00142233 PSI = 0,0393701 inH2O = 0,0735559 Tr = 0,0735559 mmHg = 0,0028959 inHg = 0,204816 PSF = 0,0001 at

mmH2O to Bar - Milimetre of water column to Bar pressure unit conversion

To convert pressure from Milimetre of water column (mmH2O) to Bar multiply the pressure in Milimetre of water column (mmH2O) by 0,0001.

• 1 mmH2O to bar? 1 mmH2O is equal to 0,0001 bar
• 2 mmH2O to bar? 2 mmH2O is equal to 0,0002 bar
• 5 mmH2O to bar? 5 mmH2O is equal to 0,0005 bar
• 10 mmH2O to bar? 10 mmH2O is equal to 0,001 bar
• 20 mmH2O to bar? 20 mmH2O is equal to 0,002 bar
• 50 mmH2O to bar? 50 mmH2O is equal to 0,005 bar
• 100 mmH2O to bar? 100 mmH2O is equal to 0,01 bar
• 200 mmH2O to bar? 200 mmH2O is equal to 0,02 bar
• 500 mmH2O to bar? 500 mmH2O is equal to 0,05 bar
• 1000 mmH2O to bar? 1000 mmH2O is equal to 0,1 bar

mmH2O to Pa - Milimetre of water column to Pascal pressure unit conversion

To convert pressure from Milimetre of water column (mmH2O) to Pascal (Pa) multiply the pressure in Milimetre of water column (mmH2O) by 9,80665.

• 1 mmH2O to Pa? 1 mmH2O is equal to 9,80665 Pa
• 2 mmH2O to Pa? 2 mmH2O is equal to 19,6133 Pa
• 5 mmH2O to Pa? 5 mmH2O is equal to 49,03325 Pa
• 10 mmH2O to Pa? 10 mmH2O is equal to 98,0665 Pa
• 20 mmH2O to Pa? 20 mmH2O is equal to 196,133 Pa
• 50 mmH2O to Pa? 50 mmH2O is equal to 490,3325 Pa
• 100 mmH2O to Pa? 100 mmH2O is equal to 980,665 Pa
• 200 mmH2O to Pa? 200 mmH2O is equal to 1961,33 Pa
• 500 mmH2O to Pa? 500 mmH2O is equal to 4903,325 Pa
• 1000 mmH2O to Pa? 1000 mmH2O is equal to 9806,65 Pa

mmH2O to hPa - Milimetre of water column to Hectopascal pressure unit conversion

To convert pressure from Milimetre of water column (mmH2O) to Hectopascal (hPa) multiply the pressure in Milimetre of water column (mmH2O) by 0,0980665.

• 1 mmH2O to hPa? 1 mmH2O is equal to 0,0980665 hPa
• 2 mmH2O to hPa? 2 mmH2O is equal to 0,196133 hPa
• 5 mmH2O to hPa? 5 mmH2O is equal to 0,4903325 hPa
• 10 mmH2O to hPa? 10 mmH2O is equal to 0,980665 hPa
• 20 mmH2O to hPa? 20 mmH2O is equal to 1,96133 hPa
• 50 mmH2O to hPa? 50 mmH2O is equal to 4,903325 hPa
• 100 mmH2O to hPa? 100 mmH2O is equal to 9,80665 hPa
• 200 mmH2O to hPa? 200 mmH2O is equal to 19,6133 hPa
• 500 mmH2O to hPa? 500 mmH2O is equal to 49,03325 hPa
• 1000 mmH2O to hPa? 1000 mmH2O is equal to 98,0665 hPa

mmH2O to kPa - Milimetre of water column to Kilopascal pressure unit conversion

To convert pressure from Milimetre of water column (mmH2O) to Kilopascal (kPa) multiply the pressure in Milimetre of water column (mmH2O) by 0,00980665.

• 1 mmH2O to kPa? 1 mmH2O is equal to 0,00980665 kPa
• 2 mmH2O to kPa? 2 mmH2O is equal to 0,0196133 kPa
• 5 mmH2O to kPa? 5 mmH2O is equal to 0,04903325 kPa
• 10 mmH2O to kPa? 10 mmH2O is equal to 0,0980665 kPa
• 20 mmH2O to kPa? 20 mmH2O is equal to 0,196133 kPa
• 50 mmH2O to kPa? 50 mmH2O is equal to 0,4903325 kPa
• 100 mmH2O to kPa? 100 mmH2O is equal to 0,980665 kPa
• 200 mmH2O to kPa? 200 mmH2O is equal to 1,96133 kPa
• 500 mmH2O to kPa? 500 mmH2O is equal to 4,903325 kPa
• 1000 mmH2O to kPa? 1000 mmH2O is equal to 9,80665 kPa

mmH2O to MPa - Milimetre of water column to Megapascal pressure unit conversion

To convert pressure from Milimetre of water column (mmH2O) to Megapascal (MPa) multiply the pressure in Milimetre of water column (mmH2O) by 0,00000980665.

• 1 mmH2O to MPa? 1 mmH2O is equal to 0,00000980665 MPa
• 2 mmH2O to MPa? 2 mmH2O is equal to 0,0000196133 MPa
• 5 mmH2O to MPa? 5 mmH2O is equal to 0,00004903325 MPa
• 10 mmH2O to MPa? 10 mmH2O is equal to 0,0000980665 MPa
• 20 mmH2O to MPa? 20 mmH2O is equal to 0,000196133 MPa
• 50 mmH2O to MPa? 50 mmH2O is equal to 0,0004903325 MPa
• 100 mmH2O to MPa? 100 mmH2O is equal to 0,000980665 MPa
• 200 mmH2O to MPa? 200 mmH2O is equal to 0,00196133 MPa
• 500 mmH2O to MPa? 500 mmH2O is equal to 0,004903325 MPa
• 1000 mmH2O to MPa? 1000 mmH2O is equal to 0,00980665 MPa

mmH2O to atm - Milimetre of water column to Atmosphere pressure unit conversion

To convert pressure from Milimetre of water column (mmH2O) to Atmosphere (atm) multiply the pressure in Milimetre of water column (mmH2O) by 0,000096784.

• 1 mmH2O to atm? 1 mmH2O is equal to 0,000096784 atm
• 2 mmH2O to atm? 2 mmH2O is equal to 0,000193568 atm
• 5 mmH2O to atm? 5 mmH2O is equal to 0,00048392 atm
• 10 mmH2O to atm? 10 mmH2O is equal to 0,00096784 atm
• 20 mmH2O to atm? 20 mmH2O is equal to 0,00193568 atm
• 50 mmH2O to atm? 50 mmH2O is equal to 0,0048392 atm
• 100 mmH2O to atm? 100 mmH2O is equal to 0,0096784 atm
• 200 mmH2O to atm? 200 mmH2O is equal to 0,0193568 atm
• 500 mmH2O to atm? 500 mmH2O is equal to 0,048392 atm
• 1000 mmH2O to atm? 1000 mmH2O is equal to 0,096784 atm

mmH2O to PSI - Milimetre of water column to PSI pressure unit conversion

To convert pressure from Milimetre of water column (mmH2O) to PSI multiply the pressure in Milimetre of water column (mmH2O) by 0,00142233.

• 1 mmH2O to PSI? 1 mmH2O is equal to 0,00142233 PSI
• 2 mmH2O to PSI? 2 mmH2O is equal to 0,00284466 PSI
• 5 mmH2O to PSI? 5 mmH2O is equal to 0,00711165 PSI
• 10 mmH2O to PSI? 10 mmH2O is equal to 0,0142233 PSI
• 20 mmH2O to PSI? 20 mmH2O is equal to 0,0284466 PSI
• 50 mmH2O to PSI? 50 mmH2O is equal to 0,0711165 PSI
• 100 mmH2O to PSI? 100 mmH2O is equal to 0,142233 PSI
• 200 mmH2O to PSI? 200 mmH2O is equal to 0,284466 PSI
• 500 mmH2O to PSI? 500 mmH2O is equal to 0,711165 PSI
• 1000 mmH2O to PSI? 1000 mmH2O is equal to 1,42233 PSI

mmH2O to inH2O - Milimetre of water column to Inch of water column pressure unit conversion

To convert pressure from Milimetre of water column (mmH2O) to Inch of water column (inH2O) multiply the pressure in Milimetre of water column (mmH2O) by 0,0393701.

• 1 mmH2O to inH2O? 1 mmH2O is equal to 0,0393701 inH2O
• 2 mmH2O to inH2O? 2 mmH2O is equal to 0,0787402 inH2O
• 5 mmH2O to inH2O? 5 mmH2O is equal to 0,1968505 inH2O
• 10 mmH2O to inH2O? 10 mmH2O is equal to 0,393701 inH2O
• 20 mmH2O to inH2O? 20 mmH2O is equal to 0,787402 inH2O
• 50 mmH2O to inH2O? 50 mmH2O is equal to 1,968505 inH2O
• 100 mmH2O to inH2O? 100 mmH2O is equal to 3,93701 inH2O
• 200 mmH2O to inH2O? 200 mmH2O is equal to 7,87402 inH2O
• 500 mmH2O to inH2O? 500 mmH2O is equal to 19,68505 inH2O
• 1000 mmH2O to inH2O? 1000 mmH2O is equal to 39,3701 inH2O

mmH2O to torr - Milimetre of water column to torr pressure unit conversion

To convert pressure from Milimetre of water column (mmH2O) to torr (Tr) multiply the pressure in Milimetre of water column (mmH2O) by 0,0735559.

• 1 mmH2O to torr? 1 mmH2O is equal to 0,0735559 torr
• 2 mmH2O to torr? 2 mmH2O is equal to 0,1471118 torr
• 5 mmH2O to torr? 5 mmH2O is equal to 0,3677795 torr
• 10 mmH2O to torr? 10 mmH2O is equal to 0,735559 torr
• 20 mmH2O to torr? 20 mmH2O is equal to 1,471118 torr
• 50 mmH2O to torr? 50 mmH2O is equal to 3,677795 torr
• 100 mmH2O to torr? 100 mmH2O is equal to 7,35559 torr
• 200 mmH2O to torr? 200 mmH2O is equal to 14,71118 torr
• 500 mmH2O to torr? 500 mmH2O is equal to 36,77795 torr
• 1000 mmH2O to torr? 1000 mmH2O is equal to 73,5559 torr

mmH2O to mmHg - Milimetre of water column to Milimetre of mercury column pressure unit conversion

To convert pressure from Milimetre of water column (mmH2O) to Milimetre of mercury column (mmHg) multiply the pressure in Milimetre of water column (mmH2O) by 0,0735559.

• 1 mmH2O to mmHg? 1 mmH2O is equal to 0,0735559 mmHg
• 2 mmH2O to mmHg? 2 mmH2O is equal to 0,1471118 mmHg
• 5 mmH2O to mmHg? 5 mmH2O is equal to 0,3677795 mmHg
• 10 mmH2O to mmHg? 10 mmH2O is equal to 0,735559 mmHg
• 20 mmH2O to mmHg? 20 mmH2O is equal to 1,471118 mmHg
• 50 mmH2O to mmHg? 50 mmH2O is equal to 3,677795 mmHg
• 100 mmH2O to mmHg? 100 mmH2O is equal to 7,35559 mmHg
• 200 mmH2O to mmHg? 200 mmH2O is equal to 14,71118 mmHg
• 500 mmH2O to mmHg? 500 mmH2O is equal to 36,77795 mmHg
• 1000 mmH2O to mmHg? 1000 mmH2O is equal to 73,5559 mmHg

mmH2O to inHg - Milimetre of water column to Inch of mercury column pressure unit conversion

To convert pressure from Milimetre of water column (mmH2O) to Inch of mercury column (inHg) multiply the pressure in Milimetre of water column (mmH2O) by 0,0028959.

• 1 mmH2O to inHg? 1 mmH2O is equal to 0,0028959 inHg
• 2 mmH2O to inHg? 2 mmH2O is equal to 0,0057918 inHg
• 5 mmH2O to inHg? 5 mmH2O is equal to 0,0144795 inHg
• 10 mmH2O to inHg? 10 mmH2O is equal to 0,028959 inHg
• 20 mmH2O to inHg? 20 mmH2O is equal to 0,057918 inHg
• 50 mmH2O to inHg? 50 mmH2O is equal to 0,144795 inHg
• 100 mmH2O to inHg? 100 mmH2O is equal to 0,28959 inHg
• 200 mmH2O to inHg? 200 mmH2O is equal to 0,57918 inHg
• 500 mmH2O to inHg? 500 mmH2O is equal to 1,44795 inHg
• 1000 mmH2O to inHg? 1000 mmH2O is equal to 2,8959 inHg

mmH2O to PSF - Milimetre of water column to PSF pressure unit conversion

To convert pressure from Milimetre of water column (mmH2O) to PSF multiply the pressure in Milimetre of water column (mmH2O) by 0,204816.

• 1 mmH2O to PSF? 1 mmH2O is equal to 0,204816 PSF
• 2 mmH2O to PSF? 2 mmH2O is equal to 0,409632 PSF
• 5 mmH2O to PSF? 5 mmH2O is equal to 1,02408 PSF
• 10 mmH2O to PSF? 10 mmH2O is equal to 2,04816 PSF
• 20 mmH2O to PSF? 20 mmH2O is equal to 4,09632 PSF
• 50 mmH2O to PSF? 50 mmH2O is equal to 10,2408 PSF
• 100 mmH2O to PSF? 100 mmH2O is equal to 20,4816 PSF
• 200 mmH2O to PSF? 200 mmH2O is equal to 40,9632 PSF
• 500 mmH2O to PSF? 500 mmH2O is equal to 102,408 PSF
• 1000 mmH2O to PSF? 1000 mmH2O is equal to 204,816 PSF

mmH2O to at - Milimetre of water column to Technical atmosphere pressure unit conversion

To convert pressure from Milimetre of water column (mmH2O) to Technical Atmosphere (at) multiply the pressure in Milimetre of water column (mmH2O) by 0,0001.

• 1 mmH2O to at? 1 mmH2O is equal to 0,0001 at
• 2 mmH2O to at? 2 mmH2O is equal to 0,0002 at
• 5 mmH2O to at? 5 mmH2O is equal to 0,0005 at
• 10 mmH2O to at? 10 mmH2O is equal to 0,001 at
• 20 mmH2O to at? 20 mmH2O is equal to 0,002 at
• 50 mmH2O to at? 50 mmH2O is equal to 0,005 at
• 100 mmH2O to at? 100 mmH2O is equal to 0,01 at
• 200 mmH2O to at? 200 mmH2O is equal to 0,02 at
• 500 mmH2O to at? 500 mmH2O is equal to 0,05 at
• 1000 mmH2O to at? 1000 mmH2O is equal to 0,1 at