Like most homeowners, if you’re in need of a new air filter you may just go to the nearest hardware store, Walmart or Costco and pick out a filter that fits your return air duct. However, doing so may not save you any money and, more importantly, not improve your health or that of your family. Just like all other home purchases that you make, there are many factors that go into choosing the right air filter – one that will perform efficiently and cost effectively. The more you know, the better able you are to make more discerning choices.
As we’ve talked about before, the first thing to understand are MERV ratings. MERV stands for Minimum Efficiently Reporting Value and it is this number that tells you the effectiveness of your chosen air filter. MERV ratings are calculated by measuring the number of particles a filter can trap compared to the number the particles its trying to filter. Basically, this means that if there are two filters in the same room, the one that traps fewer particles has a lower MERV rating.
Now that you know how to look for and understand MERV ratings, it’s important to note that this isn’t the only factor that’s involved in choosing the right filter for your AC unit. If you simply choose by selecting the filter with the highest MERV rating (higher efficiency is better than low efficiency, right?) then you may be purchasing an air filter that can make your HVAC system less efficient by blocking too much of the air flow. When this happens the system can’t heat or cool enough air to correctly control the temperature in your house. This would lead to higher energy bills and could even overheat your entire system.
So it’s all about the balance – the best choice is the filter that removes the most pollutants (MERV rating) while allowing your HVAC system to perform efficiently. Here are the four different types of filters, what their made of, their MERV and what you need to know to make the most informed decision. It may take some experimenting to find which filter works the best for your home’s HVAC system, but the more you know, the sooner you’ll find “the one”.
Made from spun fiberglass and often blue, these filters are one of the most popular. They usually have a low MERV rating between 1 and 4, catching 80% of particles 50 microns and larger and 25% of particles between 3 and 10 microns. These filters do a great job of protecting your HVAC unit from large dust particles but will not trap mold, pollen or other small particulates, therefore they are not recommended for people with allergies.
Pleated Air Filters
Comprised of folded sheets of cotton or a polyester-blend fabric, pleated filters are folded accordion style allowing a larger fabric surface in a smaller area. The more pleats, the easier air can pass through the filter making it a higher-efficiency choice with a MERV rating from 5 to 8, trapping 80-95% of particles 5 microns and larger. If you find a cotton/polyester filter with lots of pleats and a MERV value of 6 or greater, it could be your ideal air filter solution as it removes a large number of pollutants AND keeps your HVAC system working at top-notch condition.
Pleated air filters also come in high MERV ratings from 11-13 which can trap particles as small as 0.3 microns. At this efficiency level, they are about 2″-5″ thick and fit into box-like housings that are mounted onto the air handler.
Disposable Electrostatic Filters
With a MERV rating of 10 or more, these filters are very effective at decontaminating the air inside your home. Electrostatic filters are made of multiple layers of self-charging, polyester-blend fibers that create their own static charge which attracts particulates out of the air. They are framed by a polyester mesh. As air passes through positively-charged outer material, particulate matter becomes charged and is then attracted to the negatively-charged inner material. Electrostatic filters can be on the pricey side.
Washable Electrostatic Filters
Made of washable material, cased in aluminum mesh and framed in aluminum, these filters have MERV ratings of up to 10 or greater. To keep them working their best, they need to be washed about every three months and, as with all purchases, quality varies with cost. Higher quality washable electrostatic filters can last up to 8 years; however, some of them aren’t always high efficiency and its hard to tell the difference. After washing, the filters must dry completely. If they have even a little bit of moisture and placed back in the air exchange, they can grow mold and bacteria that is then circulated through your home.
US Home Filter is Here for YOU
Determining the size that your system requires and choosing the MERV rating that is best for you can be a little overwhelming, especially if you have never purchased air filters for your home or if you have a new unit or home to buy filters for. You can take a look at our air filter measurement guide to help you pick the right size or call us and we can easily assist you with ordering the exact air filter size you need and recommend the best rating for you depending on the level of filtration you want. Whether you need AC or furnace filters, a specialty Whole House filter, a Grille filter, or even a custom air filter size, we have a professional and helpful staff ready to take care of you!