Differential Pressure Sensors and Monitoring for HVAC Systems

May 1, 2020

Differential Pressure Sensors and Monitoring for HVAC Systems

In this pandemic world more than ever, we need efficient HVAC systems.

Effective differential pressure sensors and switches make or break the air quality that a good HVAC system can put out. 

Keep reading to learn everything you need to know about differential pressure sensors in HVAC systems.  

What is Differential Pressure? 

The term “differential pressure” refers to the pressure between two places. Different industries use differential pressure sensors to measure this unique type of pressure. 

In the world of pressure, three common types of pressure exist: 

  1. Differential pressure: the pressure between two points. This is the most complicated type of pressure because it has two variables. 
  2. Gauge pressure: the pressure between a measured point and the atmosphere. 
  3. Absolute pressure: the combined pressure of the atmosphere and the measured point. 

What Are Differential Pressure Switches?

Engineers have created switches called differential pressure switches. They sense the difference in pressure between these two measured points. 

These switches have two ports connected to the two different pressure sources. The differential pressure switch follows the pressure between the two places. 

If the pressure reaches a particular point, then the internal diaphragm in the switch will make contact after deflecting. This contact will either make or break a circuit. The change in the circuit will trigger an alarm that tells the user that the pressure has changed. 

Users can pre-set the setpoint on the pressure switch or they can adjust it in the field.

Why Differential Pressure Switches Matter

HVAC systems use differential pressure switches to measure flow rates and pressures in lines and rooms. These switches help a system to efficiently and economically operate heating, ventilation, and air-conditioning systems. 

The pressure sensors are the core of controlling an HVAC system. Ever-changing strict legal requirements make pressure sensors essential. They help a system to stay within the minimal energy cost requirements. 

Plus, the differential pressure sensors just make a room more comfortable, and in some cases, safer. They measure and monitor four key elements in an HVAC system. 


Differential pressures can control the volume of air that flows through your system. the pressure measurement can control the damper position in a closed-control circuit. It will also enable demand-controlled ventilation. 

This means you can control the volume at will. Pressure sensors increase the quality of volume control. 

Channel Pressure

As a differential sensor controls the ventilation dampers in a room, the pressure can change in the ventilation ducts. A differential pressure sensor can monitor the channel pressure in the ventilation ducts and then control the fan power.

So you have a steady flow of air even though the fan itself is not working at the same power all the time. 

Room Pressure

Basic air-conditioned rooms need a differential pressure sensor to keep the pressure the same in all parts of the room. But pressure sensors play an especially critical role in other types of rooms as well.

For example, clean rooms need overpressure to prevent the entry of contaminated air. Hospital rooms and laboratories need constant negative pressure to prevent germs and hazardous substances from spreading. 

A precision pressure sensor will monitor the incremental differences in pressure to keep the room at exactly the right pressure. 


If you’ve ever received a message through your HVAC system to change your filter, you can thank a differential pressure sensor. The pressure sensor will measure the pressure drop over a filter and then trigger the message to replace it. Some differential pressure monitors can even tell you if you have a torn filter. 

Wireless Pressure Transmitter

Technology has advanced enough to give us wireless differential pressure transmitters

These transmitters do everything a wireless differential pressure sensor does, but it has the convenience of using Wi-Fi to send information to a cloud. You then receive notifications about the pressure of a room via email, text, voicemail, fax, or pager. 

Differential pressure monitoring systems measure the differential pressure with the idea of minimizing the spread of infectious diseases in a particular environment. They also help keep a sterile work environment germ-free. 

Devices like those in the OTA SEries have the capability of working over the air and automatically upgrading the firmware to prevent hackers from disrupting your clean environment. You no longer have to worry about manual upgrades but can rely on automatic upgrades provided through WiFi. 

Longer Life Span

Because your device will update automatically via WiFi, it can stay on top of malicious threats. The firmware will allow the device to evolve with the needs of its software. So you will not have an outdated device because the firmware makes it up-to-date. 

Your device will last longer, and you can save money on replacing it. 

Scalable with No Disruptions

Because of their WiFi and OTA capabilities, an OTA differential pressure sensor is easily scalable. A technician can scale several devices at once and even install a new one without disrupting others. 

This also means when you update your system, you do not disrupt any single monitor. You can continue to monitor the environment. 

A Secure System

Because an OTA differential pressure monitor and sensor is constantly updating, it is a more secure system. Great companies understand that tech can keep a room safe and keep the pressure steady. 

A Solution for Today

Complicated problems require smart solutions. We are living in a time unlike any other with a complicated and nefarious foe in COVID-19. 

Differential pressure sensors help field hospitals create isolation rooms with proper pressure so the virus can stay contained in the room. 

These seals do more than just help keep the temperature regular, although they do that too. They can keep measure and regulate temperature to within 0.5 degrees. 

They also monitor pressure, carbon dioxide, light, humidity, and water leaks.

Differential Pressure: The Hidden Secret

The idea of differential pressure has existed for decades. Our world needs differential monitors and sensors more than ever to keep healthy people healthy and to allow doctors to treat the sick. 

To find the best differential pressure sensors on the market, contact us

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