The Importance of Having a Good Filter for Your Building’s Furnace
When you’re getting the furnace in your commercial building ready for another winter’s service, much of your attention will likely be focused on the equipment itself and on its functional components. There is another important piece of your furnace, however, that you should give attention to: the air filter. While it may seem that the furnace filter is mostly inert with little impact on furnace operation and indoor comfort, the truth is that the filter plays a significant role in keeping your building comfortable, maintaining high levels of indoor air quality, and sustaining HVAC system performance. Here is a brief guide to the importance of furnace filters.
Why Worry About the Furnace Filter?
The role of the furnace filter is, at base, to remove particulates and other contaminants from your indoor air. As air flows through your heating system, it also flows through the filter. The filter medium, usually a material such as spun fiberglass or pleated cloth, captures and holds particles of dust, pollen, mold, and other material that reduces your indoor air quality.
At a higher level, furnace filters contribute to the performance and efficiency of your HVAC system. Filters affect the airflow within your furnace, which impacts how well the equipment works. Filters can also influence the efficiency of a heating system, which can determine how much you pay to heat your building.
Keep in mind also that dirty filters are a major source of furnace malfunctions and breakdowns. This can increase your expenses over the course of a heating system and reduce the functional life of your furnace. If the problem is severe enough, you could even have to replace your furnace.
Furnace Filter Ratings
The effectiveness of a furnace filter is indicated by its rating, usually the Minimum Efficiency Reporting Value (MERV). The MERV rating was developed by one of the most influential trade organizations in the HVAC industry, the American Society of Heating, Refrigeration, and Air Conditioning Engineers (ASHRAE).
For standard filters, MERV ratings range from 1 to 16, with higher MERV numbers indicating greater efficiency and effectiveness at removing particulates. Extremely high MERV filters with ratings of 17 to 20 are usually found only in environments where air quality is extremely crucial, such as medical facilities, manufacturing plants, food processing lines, or computer clean rooms. These higher-level filters are referred to as High Efficiency Particulate Air (HEPA) filters and will usually require specialized mounting equipment.
In most cases, a filter with a MERV rating of 8 or more will provide good performance and filtration. Filtration effectiveness will increase with the MERV rating, but keep in mind that higher-rated MERV filters can be very thick and dense. These types of filters can interfere with HVAC system airflow and cause the same types of problems as dirty, clogged filters. Before installing a highly rated MERV filter, make sure your furnace has the functional ability to accommodate a thick filter.
Furnace Filter Changes and Maintenance
As part of seasonal preventive maintenance and preparation, you should change the filter in your furnace. During the season, the filter should be checked about every month and changed if it gets dirty. If the indoor air in your facility tends to carry significant amounts of particulates and contaminants, it may be a good idea to check the furnace filter every two weeks.
A good technique for checking the furnace filter involves holding the filter up to a light source, such as an uncovered lamp or bare light bulb. If you cannot see the light from the source shining through the filter medium, it is dirty enough to warrant a change.
Our goal is to help educate our customers about Plumbing, HVACR, Fire Protection, and Alarm Systems in Mechanical, Commercial, and Residential settings. For more information on the importance of your furnace filter to indoor comfort, HVAC system operation, and indoor air quality, and to view projects we’ve worked on, visit our website!
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