4 of the Best Types of Furnace Filters

There’s nothing better than stepping into a perfectly air-conditioned house at the end of a long, hot summer day. Unless, of course, it’s cuddling up all snug and warm with the family on a frigid December night. Your home should be a haven of comfort and a place where you and the people you love most can breathe easily. 

That’s why it’s so important to keep your home’s heating and cooling system in tiptop shape. One of the best ways is by learning about the different types of furnace filters, so you can choose the filter type that’s best for your home and family.

Why Choosing the Right Type of Furnace Filter Matters

Maintaining your home’s HVAC systems means more than keeping your family cool in the summer and warm in the winter. This effort is also going to make your system more energy-efficient, reducing your heating and cooling costs. With proper maintenance, your system also won’t have to work as hard, resulting in less wear and tear. Over time, that’s going to increase the life of your system.

And considering that the cost to replace an HVAC system averages around $7,500 in most areas, proper maintenance is well worth the time and effort. Choosing the best type of filter for your system and your family’s needs and cleaning or replacing furnace filters often is key to nurturing your HVAC through years of long life and great performance.

When differentiating between furnace filter types, one of the most important things to consider is the filter’s minimum efficiency reporting value or MERV. The MERV scale ranges from one to 20 and measures three things:

• Ability to remove air particles

• Airflow resistance

• Average life expectancy

Here’s what you need to know about the different types of furnace filters and how to find the one that’s right for you.

Pleated Media Filters

If you’re looking for clean air at a reasonable price, then you can’t go wrong with pleated media filters. These filters are made from tightly woven cotton media, which, when combined with the pleated surface, makes them a rockstar at filtering out small particles in the air, such as dust and dust mites.

These filters typically come in two varieties: disposable and permanent. Disposable pleated media filters usually cost around $5. But there’s a tradeoff because these filters need to be replaced frequently, sometimes as often as once a month, to avoid clogging your system. And that makes the filters less efficient than other types, earning them an average MERV rating of around six.

Permanent pleated filters, on the other hand, do not need to be replaced, but they’ll take a hit on your wallet, running as much as $100 per filter. In exchange, though, you get some of the best air filtration available. Because permanent pleated filters are great at clearing the air of small particles, and because they’re made to last, they generally have a MERV rating of between 14 and 16.  

But as with so many great things, there’s a catch. The tight cotton weave that makes permanent pleated filters so great at catching small particles also makes them highly resistant to airflow. This feature makes them most appropriate for larger, industrial HVAC systems, such as those found in hospitals. They’re usually a bit too air resistant for most residential systems to handle.

Flat-Panel Fiberglass Filters

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As the name suggests, flat-panel fiberglass filters don’t feature the air-filtering pleats of the pleated media filters mentioned above. These types of furnace filters may help protect your HVAC system, but they don’t provide any air filtration at all. Generally, they filter less than 10% of air pollutants, mostly large particles. Not surprisingly, flat-panel fiberglass filters don’t rank very highly on the MERV scale, generally earning a MERV rating of four or less.

But if you’re looking to save money, these filters can’t be beat, as they cost around $1 each. So if you’re on a tight budget and you don’t have any particular concerns about indoor air quality, then these filters may be right for you.

A word of caution, though: If you have pets (and pet dander) or if you or anyone in your family suffers from allergies or respiratory issues, such as asthma, you should probably settle on a different type of filter.

Washable Filters

If you’re looking for an environmentally friendly option, then washable filters may be right for you. Instead of having to replace your furnace filter several times a year, you simply wash and reinstall them once a month or so. These filters also tend to be less costly than other types, ranging from $20 to $50 and can last as long as eight years. They’re also good at filtering some types of common contaminants, such as dust and pollen.

But, despite the benefits, there are also some pretty big drawbacks to washable filters. They’re very high maintenance, requiring you to wash your filters regularly if you want to keep the air relatively clean and the system working well.

These filters also tend to accumulate airborne nasties, such as bacteria and fungi, which may then recirculate through your HVAC system. This is why washable filters generally score between four and eight on the MERV scale.

HEPA Filters

If you’re looking for the gold standard in air filtration, then look no further than a HEPA filter. According to the EPA, a HEPA filter can remove up to 99.97% of contaminants from your indoor air.

And that means that HEPA filters are champions at removing even airborne microparticles, including some viruses. For this reason, they sit at the top of the MERV scale, generally earning a rating of between 17 and 20. 

The bad news, though, is that some residential HVAC systems just aren’t built to work with HEPA filters. The same technology that makes HEPA filters so great at capturing small particles also makes them highly resistant to airflow, which can make your HVAC system run less efficiently and work harder. 

So you’ll want to look for signs that your system may be struggling when you install a HEPA filter, such as by heating or cooling less well than usual. If that’s the case, consider choosing a different type of filter for your HVAC and then supplementing with a HEPA air purifier instead.

Understanding the MERV Scale

As you’ve probably noticed by now, the MERV scale is one of the best ways to distinguish between different types of filters. So knowing how to read the scale can help you find the right filter for the kind of airborne contaminants present in your home.

• 0 to 6: A MERV rating of six or under means the filter can clear the air of some small particles, including dust, pollen, lint, dust mites, and mold

• 7 to 11: This rating means the filter clears everything the six and below filter does, plus pet dander, smoke, smog, and allergens

• 12 to 13: These are higher grade filters that, in addition to the contaminants above, can also filter bacteria and viruses

• Above 13: These filters can clear all of the above contaminants and produce filtration levels that are ideal for those with severe allergies and respiratory concerns