A furnace filter protects you and your loved ones from inhaling polluted air recirculated by the blower. It also protects your HVAC system by trapping particles such as dust, dander, and dirt that would otherwise build up in your heater or clog your ductwork. It’s best to choose an air filter wisely because a furnace with the wrong air filter can’t work efficiently. Replacing your air filter every one to three months can prevent it from malfunctioning while improving your indoor air quality and lowering energy costs.

There are several types of air filters to choose from, based on your goals for indoor air quality and how regularly you want to change the filter. Most air filters are disposable, but there are permanent options as well if you’re willing to clean the furnace filter occasionally. The filter material plays an integral role in determining its efficiency and lifespan. Furnace filters get rated by MERV (minimum efficiency reporting value). The higher the rating, the more effective the filter is at trapping impurities. The numerical range falls between 1 and 20.

Here are some of the best furnace filters available on the market.

Disposable Fiberglass

A disposable fiberglass furnace filter is a common choice among homeowners. Formed from 1-inch thick fiberglass, this type of furnace filter prevents larger particles such as lint, dust, and debris from entering your HVAC system. They have MERV ratings of 2-3 and cost about $1-$2. Although they’re affordable and suitable for those without asthma or allergies, they don’t clean the air as effectively as some other options.

High-Efficiency Pleated

High-efficiency pleated filters are one of the best furnace filters available on the market. They’re made from 4- to 5-inch thick pleated artificial cotton attached to a robust metallic grid to prevent fluttering or leaks. These filters come with a hefty price tag of around $100 and a perfect MERV rating of 14-16, making them ideal for hospital applications. These filters are designed to be used in special housing because of their thickness, so using them at home can be quite challenging. However, they can filter even the smallest particulates and may benefit individuals with autoimmune disorders or respiratory issues.

Disposable Pleated

Disposable pleated furnace filters are a popular choice and made from cotton or polyester. They can effectively remove tiny particles like mites and spores for improved air quality but have to be replaced regularly to avoid clogging and burdening your HVAC system. With a MERV rating of 6, these filters cost $4-$5. Although relatively affordable, these options are made from green materials and capture some tiny particles. However, they increase resistance to airflow, making your furnace inefficient.

Disposable Electrostatic

Disposable electrostatic furnace filters feature self-charging electrostatic paper or cotton fibers that attract and capture small particles. They have a MERV rating of 10 and are reasonably priced in standard sizes. Disposable electrostatic filters are ideal for households with pets, smokers, or children. Custom sizes are costly, resulting in higher costs if changed regularly.

Reusable Electrostatic

Similar to disposable electrostatic filters, reusable electrostatic filters feature self-charging cotton fibers that trap particles. Permanent reusable electrostatic filters are removable and washable, meaning you can reuse them for an extended period. They have a MERV rating of 8 and produce little waste. They’re also more effective than pleated furnace filters and an ideal choice if you buy a standard size. However, they’re less efficient than electrostatic options, and custom sizes can be costly.


HEPA (high-efficiency particulate) air filters filter up to 99.7% of airborne particles that are 0.3 microns or bigger. However, they’re not available in sizes to fit standard furnaces and need to be changed every three months to work as expected. Although HEPA filters have a MERV rating of 16-20, trap the highest level of particulates, and offer better indoor air quality, they’re not fit for most residential HVAC systems.


Polyester furnace filters are reusable, and they trap more particulates than fiberglass furnace filters and come in either pleated or flat versions. With a MERV rating of 8, they trap about 91% of airborne particles, including dust and pollen. However, these filters don’t eliminate the need to clean HVAC coils or filters occasionally because some particles still pass through them.

Putnam Mechanical offers exceptional heating and air conditioning services in Mooresville, NC, and the nearby areas. Our NATE-certified technicians can handle heating and air conditioning installation, repair, and maintenance.

To find out more about the best filters for your HVAC system, our service rates, or to get a free cost estimate for your upcoming cooling or heating project, contact us today.

company icon