Fiberglass? HEPA? Cotton? Oh My! A Guide To Buying Furnace Filters

20 July 2016
 Categories: , Blog

You wouldn't think buying a furnace filter would be complicated, but when you're standing in the hardware store aisle with 30 different filters to choose from, it can be hard to know what one's the right one for you. First, you'll want to ensure you have the right size. (Bring your old filter with you to make sure.) Then, you'll need to pick the right filter type. Here's a closer look at what each common type of filter really is – and the pros and cons to keep in mind as you shop.


These are the standard, flimsy filters you can pick up for a dollar or two. Chances are, your HVAC tech put this type in your furnace originally. Fiberglass filters do an okay job. They catch most bigger particles like dust and pet hair, but they will let through a lot of smaller particles like mold spores and pet dander. If you live in a home with little dust, no pets, and you don't have allergies, then you'll probably be just fine with this type of filter. However, pet owners and allergy sufferers typically want something with a bit more trapping power.


Cotton filters may cost a little more than fiberglass filters, though they're still very affordable. They work about the same as a fiberglass filter, but their main selling point is that they're more eco-friendly since cotton is natural and biodegradable. If you're a fan of green living and on a budget, a cotton filter may be right for you.


Allergy sufferers and pet owners – this is the filter you'll want. HEPA stands for "high efficiency particulate air." This type of filter is designed to trap all of the tiny particles – like mold spores and pet dander – that other filters may let through. You'll pay a bit more for a HEPA filter than for a standard fiberglass or cotton one, but it will pay you back by doing a better job.


Washable filters cost more upfront, but they'll save you money long-term since you won't have to keep buying new filters. You just wash and reuse this style of filter over and over again. Washable filters typically are designed to catch the smallest of particles effectively. The downfall of this filter type is that you'll need to give it time to dry before you re-insert it in your furnace. If your climate is such that you can do without heat for a day or so while it dries, this shouldn't be too bad. If going without heat for a day would be impossible for you, then you may want to buy two washable filters so you have a substitute to use while the other is drying. Talk to a contractor, like Advanced Air Heating & Cooling Services, for more help.