Do Filters Reduce Airflow? An Expert's Guide

Dirty air filters can have a major effect on air flow, making it hard for the air conditioning system to work correctly. The fan motor stops the compressor in the air conditioning unit from overheating, and when an air filter is too effective, it can cause low airflow. To assess the effectiveness of your air filter, you should check your minimum rated efficiency value (MERV) rating. Ratings range from 1 (the lowest possible filter) to 20 (the highest possible filter).

Generally, the higher the MERV rating of an air filter, the fewer dust particles and contaminants can pass through it. However, sometimes high-efficiency air filters can work so well that they make the HVAC system less efficient because they block the air flow too much. This can lead to higher energy bills and could even damage the boiler if it overheats. So what's the best air filter for your home? One that removes most contaminants from the air, but allows your HVAC system to do its job effortlessly.

There are four main types of air filters available, and each has its own advantages and disadvantages. Usually, a filter with a higher MERV rating will reduce airflow. However, there are many other factors at play, such as the size of the filter and the type of fan motor in your HVAC system. The short answer is yes, filters do reduce airflow, but it's not really a problem except in extreme circumstances.

Most modern HVAC systems have no problem working with higher MERV filters. The main risk of high-efficiency air filters is that they remain unchanged for long periods of time. If you don't get tired of changing your filters regularly, you're unlikely to have any problems related to the filters in your air conditioning system. You can easily observe how the air filter reduces the total external static pressure by increasing the pressure drop. A consequence of a highly effective air filter is the speed with which it can become loaded with contaminants and begin to increase the pressure drop.

It can be comforting to know that your outdated filter isn't as bad as it could be, but it won't do anything else for you until you replace it. HVAC unit technology has advanced since then, and most modern units in recent years should be able to have at least one MERV 8 filter. Some HVAC technicians prefer these low-efficiency filters because of their low resistance to airflow. Once a filter starts filtering these small particles (0.3 to 1.0 microns), it is at a level close to MERV 13. The trick is to maximize the area of the filter face to get the lowest possible pressure drop. First, the filter takes long enough to charge for a beneficial effect, so that everything that passes through the filter ends up in your system or in your home.

Air filters with the MERV 13 standard or higher are recommended for those who prioritize air quality and may have to deal with asthma, severe allergies and other similar circumstances. Since the air filters in many residential homes generate more than half of that pressure, it's clear that air filters are responsible for a large part of the pressure drop in an air conditioning system. Depending on the type of air filter you use and the performance of the system, it's best to clean or replace it every 30 to 90 days. In conclusion, yes, filters do reduce airflow but this is not usually a problem unless in extreme cases. Most modern HVAC systems are designed to work with higher MERV filters without any issues. The main risk associated with high-efficiency air filters is that they remain unchanged for long periods of time which can lead to higher energy bills and even damage to your boiler if it overheats.