HVAC systems have many needs. Every utility system needs a fuel source—usually gas for the furnace and electricity for the air conditioner. However, some homes go all-electric year-round, while others rely on heating oil tanks in the fall and winter. Regardless, you need ductwork to circulate the air. No less important to the process is the filter, a small but mighty accessory that traps incoming airborne particles. The filtration market is full of different types of products that fulfill the same task. We’ll help you sort through them with this guide to understanding the different types of furnace filters.
Furnace Filters, AC Filters, Air Filters, and HVAC Filters… Oh My
Let’s begin by clearing up a great and pesky ambiguity in the filter industry. Have you ever found yourself standing in the aisle of a grocery store, trying to decide whether you should buy chickpeas or garbanzo beans? Perhaps you’ve seen some unusual wildlife in your yard and tried to figure out whether that big cat that just walked by was a puma or a mountain lion. So it goes with furnace filters, AC filters, and the rest; it’s one item with multiple names. The difference tends to be regional. If you live in a climate with cold winters, you’re more likely to know it as your furnace filter. Down south, where central air conditioning is much more important than heating, you’ll call it your air filter or your AC filter. Whether the air is warm or cool, it’s the same filter doing the same job—trapping tiny particles that can harm the inner workings of your HVAC system and bother your breathing. While these various modifiers all take you to the same place, we can further subdivide the filter family along clearer lines. Let’s break it down.
The accordion is not exactly the most popular musical instrument. However, picturing the accordion folds is a good way to understand the appearance of the most popular types of filters on the market. Meet the pleated filter, whose material (usually paper, cotton, or polyester) almost resembles a squeezebox. However, this membrane doesn’t expand or contract. And while it doesn’t generate any music, either, its increased efficacy against airborne particles could still be music to your ears. Pleated filter selections from Remember the Filter boast MERV ratings ranging from eight to 13, which is the highest possible rating for superior residential HVAC systems. This makes them ideal choices for systems that are up to the task. Just like other disposable filters, you’ll have to switch these out every one to three months. But the higher the rating, the harder your filter will have to work, meaning that you can expect more frequent substitutions.
When you think of fiberglass, you probably think of household insulation—that pink building material that looks to all the world like fluffy cotton candy but is very much a hands-off substance. You may be surprised to learn that fiberglass also finds use in affordable alternatives to more traditional polyester filters. A fiberglass filter is one of the most inexpensive options for air filtration on the market, though it’s not a perfect fit for every HVAC system or the people in the house. While you won’t pay much for fiberglass filters, you won’t enjoy high MERV ratings either. This means that, while the fibers will catch the big particles, they’ll allow smaller ones to pass through and stay in circulation. Furthermore, although pleated filters can last up to 90 days if they don’t have to work too hard, a fiberglass filter generally has a 30-day lifespan, even without a commensurately high MERV. However, if you don’t have to worry about respiratory sensitivities and like to keep your HVAC system simple, a fiberglass filter can slot right in.
Most filters on the market are disposable and intended for 30 to 90 days of service before retirement. But green-minded consumers who don’t mind paying a little more can commit to a filter that can last for up to 10 years with proper care. A washable furnace filter is an eco-friendly alternative to disposable models. Though it can be cost-effective and environmentally friendly, a washable filter does come with drawbacks, though. Most notably, washable models come with decidedly lower MERV ratings than their disposable counterparts. Most reusable filters have a MERV that maxes out at only four. This rating means that they’re effective against pollen, dust mites, and loose carpet fibers but allow mold spores, cooking byproducts, and hair sprays to pass through. If you or someone in your household suffers from environmental allergies or is generally sensitive to common household irritants, a washable filter may not provide sufficient filtration for your home. Also, homeowners with washable filters must wash and dry them with care. Being content to let your filter dry in a dark and damp area like your basement or a bathroom will cause the material to begin harboring mold colonies. And that’s the last thing you want this important piece of equipment to do. If you can responsibly care for your filter and a lower MERV rating doesn’t concern you, a washable filter could be the smart choice. With one, you’ll lower your HVAC waste and expenses.
We conclude with high-efficiency particulate air, or HEPA, filters. While HEPA filters are usually part of freestanding air purifiers, some homes have HEPA filters installed as part of the central air system, where they work hard to clean the air close to the furnace. Some HEPA filters include ultraviolet lights that denature and neutralize cellular organisms as they pass through to kill live pathogens. Others further bolster their efficacy by utilizing activated carbon. Unlike the more familiar filter construction comprised of a frame and a membrane of some sort, a HEPA HVAC filter is a much more complicated unit, and it’s not fit for every home.
Remember Every Kind of Filter
This guide should give you a better understanding of the different types of furnace filters—or air conditioning filters, or however you’d like to refer to them. With summer in swing, Remember the Filter carries all these varieties of air conditioning filters online, ensuring that whichever model suits you and your needs, you can have it arrive at your doorstep. Whether it’s fiberglass, pleated, or washable, we have the filter for you.