Most HVAC air filters look the same. This can make picking the right one challenging for anyone, even the most DIY-savvy homeowner. 

Without the right prior knowledge, you can become overrun by unanswered questions:

• Which HVAC air filter best fits my needs? 
• Does a higher price mean a better product? 
• Do these filters actually improve the air quality in my home?
• Which one do I pick?!

Get all these questions – and more – answered below as we walk through the steps you should take when choosing new air filters for your home.

What do I need to know before I buy any new air filters?

Before you make any sort of air filter purchase, there are a few pieces of helpful data you’ll need to gather:

• The size of your filter. Air filters come in different shapes and sizes depending on the unique makeup of your home’s furnace or air handler. In order to properly gauge the size of the air filter you need to purchase, you’ll have to take a measurement. Here’s how:
  • On furnaces, you’re most likely to find the filter slot between the return air duct and the furnace assembly. This can sometimes be behind an openable or removable metal door. Otherwise, you can find filter slots next to your return air vents. Open things up and pull out your filter to measure. 
  • Measure its length, width, and depth and then you’ll have the size you need to purchase! Alternately, you could just take the filter with you and match it to a similarly sized one in-store.

• The MERV rating you want. MERV is an acronym that stands for Minimum Efficiency Reporting Values. An air filter’s MERV rating defines its ability to capture large particles (dust, debris, irritants) within specific measurement parameters. 
  • To learn more about the intricacies of MERV ratings and how to determine which one you most need, check out our HVAC Terms Defined blog on the topic.

• The last time you changed your filters. This won’t impact the filter you get, but it can influence how long you can safely wait until you change them out. Depending on the type of filter, frequencies vary, but you should be changing them out every few months if you want to keep things fresh.

• Where to go to buy them. You’ll be able to find replacement air filters at any home goods or hardware store. You can also find them at big box stores like Target or Walmart, though they tend to have less of a selection.

What kind of air filter should I get?

Once you know what size air filter to get, what MERV rating you want, and where to go to purchase… It’s time to pick your type. There are three main varieties of commonly used HVAC air filters: fiberglass, pleated, and HEPA filters. Here’s how they compare:

• Fiberglass filters are the most commonly found and used type of HVAC air filter. They’re made from woven fiberglass fibers reinforced by metal grating and are meant to be thrown away after use. They’re the cheapest and most accessible filter and will work just fine in most homes, but they aren’t the best available option.
• Pleated filters have a lot in common with fiberglass filters except their weave is tighter and they possess better airflow resistance and superior tiny-particle stopping abilities. If fiberglass filters were given a C grade, pleated filters would get a B.
• HEPA filters are the finest (literally) of the three options listed. HEPA stands for High Efficiency Particulate Arrestance, meaning that they possess the best MERV ratings and particulate stopping power. This type of filter isn’t necessarily needed for basic home use, but if you’re dedicated to having the best possible HVAC air filter then we recommend them as your choice. 

The right air filters taken care of with the right maintenance can make all the difference for someone seeking a comfortable, easy-breathing home. If you’d like to learn more about how changing or upgrading your air filters can impact your home’s entire HVAC system, we recommend getting in touch with our expert team at Welter Heating!