Ever wondered how your AC ensures that the air it's circulating is clean and free of pollutants? It's all thanks to the humble air filter!
One of the most under-appreciated parts of an AC or HVAC system, AC filters come in the form of pleated sheets paper or cloth enclosed in a cardboard frame or boxes made of spun fiberglass material. Their job to clean the air that circulates through your home or business while also forming the first line of defense against larger objects like pieces of loose insulation that can get dislodged from piping and present a fire risk . Filters also work to stop pollen, dust, and other allergens from entering your home and lowering the indoor air quality. With regular maintenance, AC filters also extend the life of your unit by ensuring an unobstructed flow of clean air, and stopping small particles from getting into your system and wreaking havoc.
AC filters trap dust, dirt, mold, spores, fibres, lint, metal/plaster and wood particles, hair and animal fur, and bacteria and microorganisms. They spring into action when expended air is brought back into the HVAC equipment to be conditioned and distributed again. The air is then forced through the filter, which removes particulates and other contaminants before spewing it back out again.
As with any device, not all air filters are created the same. They vary in efficiency based on their quality and micron count, which determines how fine the filter mesh is. Filter efficiency and performance is often indicated by the filters’ minimum efficiency reporting value, or MERV rating. Standard MERV values range from 1 to 16, with the number serving as an indicator of how well the filter will remove material from the air. Higher MERV numbers indicate better filtration, and these filters are capable of removing very small particulates of 0.3 microns or larger from your indoor air, for an understandably higher cost. Specialised air filters with MERV ratings higher than 16 are also available in the market, though these tend to be so thick and dense that they're prone to frequent clogging, interfering with airflow, reducing your heating and cooling effectiveness, and eventually damaging your HVAC system by restricting airflow.
With their high upkeep, air filters can sometimes seem to be quite troublesome. After all, dirty, clogged air filters are the primary source of HVAC system malfunctions world over. Aside from this, clogged filters can also reduce the airflow inside the HVAC system, which can cause air-handling fans to work harder and wear out quicker; cause contaminants to accumulate in your HVAC system’s ductwork; cause your HVAC fans to work harder to push air, increasing energy usage and unnecessarily driving up your monthly energy bills; provide a space for moisture to gather, encouraging the growth of mold or bacteria colonies; and lowering air circulation, causing particulates to settle in ducts, resulting in an ongoing drain to your system efficiency and a long-term source of pollutants in your air supply.
Still, the benefits that air filters provide to your health and air quality, especially if you're living in a space with people who have allergies, asthma, or sinus issues is worth the hassle. Keeping your HVAC units working at peak performance is as simple as checking and changing your air filters every month or two. A simple visual inspection should show you whether the filters are dirty or clogged. Hold the filter up to a light source; if you can’t see the light through the filter, it should be changed. This is an inexpensive fix that doesn't require a professional, and can save your hundreds of riyals in AC issues down the line. In most cases, you should simply be able to slide the old filter out and slide a new one in.
These days, there are a range of filters available in the market, each with their own benefits. Fibreglass filters are usually the most affordable of the bunch, though they offer the lower straining ability and work better in protecting your air conditioning system than screening dust and pollutants in the air. Meanwhile, pleated air filters made of cotton or polyester are more effective in filtering dust and other pollutants while electrostatic air filters use an electrostatic charge to magnetise dust and airborne particles and prevent them from being distributed in your home, and UV filters use ultraviolet lights to kill bacteria and viruses in the air. You can also opt to pay more upfront for the slightly more expensive washable air filters. These can be removed and cleaned often - so you don’t need to constantly replace them - which can save you big in the long run.
A handy tip: When buying a new air filter, make sure to check your unit’s manual to determine what size of filter you need, and what minimum efficiency reporting value (MERV) range it should fall into. A high MERV filter with a very tight mesh may be too much for some units, resulting in a situation a lot like a clogged air filter, even just after you’ve changed it, so take extra care to get this one right.
If you're confused or just need some more information about air filters in Doha, Qatar, take a look at our handy list of local filtration experts below.