When you contact Althoff Industries for a clean and check or problem call, one of the factors we will always check is static pressure. What is static pressure and why is it so critical to the performance of your HVAC system? How and why is it checked and how do air filters impact static pressure?

What is Static Pressure?

Static pressure is essentially air flow. It can be compared to your blood pressure because it is important to measure it and keep the numbers low. Static pressure or air flow is said to be the cause of 75% of HVAC problems.

There are two major causes of air-flow issues; static and friction. When air-flow is restricted by a surface or dirt, like that inside ductwork, it is slowed by friction. Friction is also at play when air flows through a filter. Turbulence in air flow is generally caused by bends, angles, and curves in the ductwork. The less turbulence, the less restricted the air flow will be.

How is it Checked?

Static pressure is measured with a pressure instrument called a manometer. Using two different measuring probes, static pressure can be measured at different points in the HVAC system. We generally measure static pressure before and after the air filter, to determine the effect the filter is having on air flow.

Why is it Checked?

Measuring static pressure provides real data from which our technicians can plan their next step. It minimizes guesswork in the diagnostic process. A high reading on the manometer is an indication of poor air flow. It will then be up to the technician to determine the cause, and resolution, to the air flow problem.

How Filters Impact Static Pressure

Many feel that the purpose of air filters is to just keep the air clean. Pleated filters have become more popular for this reason because they trap more particles. The problem is, a filter must also strike an optimum balance between clean air and air flow for peak equipment performance. Some pleated filters can restrict air flow, increasing static pressure and producing higher numbers on a manometer. Dirty filters can have a similar effect. We’ve produced a brief video below that shows the use of a manometer in the field and the difference a clean and clogged filter will have on static pressure.

In many cases, we will recommend changing less restrictive air filters more often as opposed to using longer-lasting, more restrictive pleated filters. This will allow your system to “breathe” easier while maintaining clean air in the home.


Measuring First and Measuring Last

At Althoff Industries, we make a point of taking measurements first, to set a baseline on the performance and safety of your HVAC equipment. Following an annual HVAC maintenance check or service call, we will then take measurements to see the effects of our efforts. When we leave your home, we both can feel good not only about the performance of your system but the safety of your family.

At Althoff Industries, we have built our reputation on providing superior service on each and every call. Our highly-trained technicians have access to the latest diagnostic equipment to promptly zero in on any problems with your system. If it is determined a part needs replaced, we will not just replace that part but work hard in determining the root cause of that part failure.

Expect more and get more from your HVAC company by calling Althoff Industries, serving Chicagoland for over 50 years.

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