Tips For Choosing The Right Furnace Filter & How To Change Your Furnace Filter

August 23, 2021

How To Choose The Right Furnace Filter

Although they seem small in comparison to the size of the whole HVAC system, furnace filters play a big role in your home comfort. Using the wrong type of furnace filter or not replacing your filter regularly could result in poorer air quality and strain on your furnace equipment.

But how do you go about choosing the right furnace filter? And how often do you change your furnace filter? We’ll go over everything you need to know about furnace filter MERV ratings, filter sizes and more.

Things To Consider When Buying A New Furnace Filter

There are numerous factors to consider when buying an HVAC air filter. Some factors, like the furnace filter size, are determined by the specifications of your HVAC equipment. Other things, such as the type of furnace filter and the price, are based on your personal preference and budget.

Furnace Filter Size

Furnace filter sizes are entirely determined by your furnace. The best way to check for the proper size of your furnace filter is to look at your old one. The filter size should be printed on one of the edges. If the filter size is not printed on the edge of the old filter, or if the old filter is the wrong size, the correct size may be printed somewhere near the filter box on the furnace itself. You’ll typically find these sizes in hardware and home improvement stores:

Common Furnace Filter Sizes

  • 16x20x1
  • 20x20x1
  • 16x25x1
  • 20x25x1

One of the smallest standard furnace filter sizes is 10x10, and one of the largest is 25x25. Many furnace filters are 1 inch thick, but they can be up to 6 inches thick.

Most Common Types Of Furnace Filters In Iowa

While furnace filter size is dictated by the size of your furnace, you can typically choose what type of furnace filter you’d like to use. In choosing the right furnace filter for your furnace, consider what the filter is made of, what upkeep is required and what its MERV rating is. Furnace filter MERV ratings range from 1-16, with 1 being the least effective at filtering out particles and 16 being the most effective and efficient. Here are some of the most common types of HVAC air filters found in Iowa homes:

Disposable Fiberglass HVAC Air Filters

  • Composition: Fiberglass mesh stretched over a cardboard framework
  • MERV rating: 1-4
  • Price: Inexpensive
  • Reusability: None. Fiberglass HVAC filters are single-use filters

Flat-panel filters catch debris as the air passes through. Disposable fiberglass HVAC filters are the most common and most affordable type of furnace filter, but they must be regularly replaced in order to maintain HVAC efficiency and air quality.

Washable Mechanical HVAC Air Filters

  • Composition: Woven polypropylene media with electrostatic charge
  • MERV rating: 1-4
  • Price: More expensive
  • Reusability: Washable HVAC filters can be washed and reused

Washable or reusable filters can be rinsed with water or vacuumed to remove any ­particle buildup. Because they can be reused, washable air filters are more eco-friendly than disposable fiberglass filters, but they are also more expensive.

Disposable Pleated HVAC Air Filters

  • Composition: Dense, pleated layers of cotton or plastic fibers
  • MERV rating: 5-12
  • Price: More expensive
  • Reusability: None. Pleated HVAC filters are disposable

Disposable pleated HVAC air filters are single-use air filters with pleated layers, which provides more surface area to catch particles.

HEPA Furnace Filters

  • Composition: Borosilicate glass fibers or plastic fibers
  • MERV rating: 16+
  • Price: Most expensive
  • Reusability: HEPA furnace filters are available in disposable or washable options

HEPA stands for High Efficiency Particulate Air. HEPA filters are highly effective at removing particles from the air. HEPA furnace filters are commonly used in settings such as medical clinics, hospitals and laboratories, where extremely pure air is especially important.

UV HVAC Air Filters

  • Composition: Ultraviolet light
  • MERV rating: N/A. UV filters are not given MERV ratings like other types of filters
  • Price: Most expensive
  • Reusability: N/A. Because there is no physical filter, UV HVAC filters are neither washable or disposable

UV filters use the disinfecting power of ultraviolet light to eliminate airborne particles, including pathogens and microorganisms like viruses, bacteria and mold. UV air filters are often used to supplement another type of air filtration system.

How To Change Your Furnace Filter

The furnace filter can be tricky to locate. If you are unsure where the filter box is, look at the ductwork. The heating duct is located near or at the top of the furnace, and the cold air return is located near the bottom, which is where the filter box will likely be located. Once you’ve located the filter box, follow these steps to replace your furnace filter. These steps may differ slightly depending on your furnace equipment. 

  1. Locate the filter box door, or possibly a notch that the filter slides into.
  2. From here, remove the old filter and discard.
  3. Look at your new filter and find the air flow arrows along the sides. The arrows indicate the correct orientation of the filter.
  4. With the arrows pointing towards the furnace, slide the furnace filter in the air box.

How Often To Change Your Furnace Filter

There is no standardized rule about how often to change your furnace filter, but the ideal cadence for replacing most furnace filters is at least once every 3 months. If you are sensitive to airborne allergens or if you have pets in your household, it can be a good idea to replace your furnace filter every month.

It’s worth checking the specifications of your system, as furnace filter recommendations can vary.

Still Not Sure If You’re Choosing The Right Furnace Filter? Call Lozier!

If you have more questions about choosing the right furnace filter or how to change your furnace filter, call the furnace experts at Lozier Heating & Cooling. A technician can come out and provide a furnace inspection, along with filter recommendations based on your setup and your household needs. Request an inspection appointment or give us a call today at 515-267-1000!