Role of filters in HVAC

The filters in your HVAC system are the first and most effective measure in protecting your heating and cooling system. Any HVAC specialist or home improvement guru will tell you, change your filters often. Keeping your system in fresh filters will greatly extend its life expectancy and this small bit of preventative maintenance can save you money on repairs down the road, not to mention help keep up the air quality in your place.
Although some products claim to be effective for ninety days or even longer, most industry experts recommend changing your filters every thirty days. In any case, you should inspect your filters regularly, as often as once a week, as the age of your HVAC system and the level of usage will determine how much wear and tear a filter suffers.
You know it is time to change your filters when it is coated in thick dust, usually gray or black. When a filter is clogged up like that, not only is it no longer doing its job, it is decreasing the efficiency of your heating system as the trapped dust absorbs heat. Plus, it also creates a serious fire hazard.
What filter is best for your? That depends mostly on your budget and the level of effort you want to put into maintaining your air conditioning system.
Fiberglass Filters:
These are your standard filters for a homeowner on a budget. Basically composed of several layers of fiberglass meshing, these filter particulates by physically trapping them in a dense net. While fiberglass filters are better than nothing, they are apt to clog quickly and allow a large percentage of smaller particulates to get through.
Electrostatic Filters:
These filters are made from a material that generates an electrostatic charge as air flows through them. This static charge acts like a magnet for dust particles, attracting them and locking them into the filter. These are generally considered more effective than fiberglass filters, especially for residents with asthma, allergies or other respiratory problems, but should still be replaced at least monthly to get their full benefit.
Electronic Filters:
These filters operate by either drawing particles in with an artificially generated electrostatic charge, or by passing air through an ionizing device to charge the air around it and create an attraction between airborne particles and the filter. In either case, these filters are plugged into a power source and only need to be cleaned rather than replaced. These are generally considered the top of the line in filtration systems, and come with a commensurate increase in price.
Specialty Filters:
There are a number of companies offering specialized filter options to combat specific air quality issues. Some come pretreated with disinfectants so they not only capture particulate matter but also kill airborne bacteria or viruses that pass through, making them a good choice for the immune-suppressed, or households with children or elderly residents.
Filters containing activated charcoal or carbon are available that can reduce foul odors if a household has that problem. HEPA and micro-particle filters are generally considered the best for improving air quality in the building, and can even be found as freestanding air purifiers if you don’t want to have one built into your HVAC.
Ultimately your choice in air filter comes down to budget vs. quality. For most homeowners, a standard fiberglass filter will do the trick, but for homes with older ductwork or residents with special respiratory needs, you may need to upgrade to a more effective and therefore more expensive alternative.