HVAC Pressure Drop: FAQ for Building Operators

What Is Pressure Drop and How Is it Affected by Air Filters?

Somewhere in your system, there are fans blowing air through the ducts. Anything in the pathway of this air is going to cause resistance. Pressure drop is the impact of this resistance on the flow of air through your system, and air filters can directly impact this.

Sources of pressure drop include many typical things you expect to find in any HVAC system: gauges, filters, coils, and even turns in the ducts cause resistance. When air filters or coils become dirty, pressure drop increases. Some filters are specifically designed to reduce pressure drop, but they cannot be eliminated—it’s impossible to filter the air without causing some resistance.

How Does Pressure Drop Affect Operating Costs?

Optimizing your HVAC filters can reduce pressure drop and generate substantial savings. This optimization includes two main components:

Using the best air filters for your facility. In many cases, the potential savings from reduced energy use will exceed the extra cost of purchasing a premium filter to minimize pressure drop.

Keeping your filters clean and well-maintained. Changing filters on the recommended schedule and ensuring no dust or debris build-up will help minimize pressure drop.

It’s important not to oversimplify the equation here. To determine the most cost-effective option, you must consider multiple factors: filtration efficiency, pressure drop, and filter price.