often to change furnace filter

To keep your heating and cooling system clean and running efficiently, a furnace filter is an absolute must. It keeps harmful airborne particles like dust and pet dander from becoming stuck in the HVAC system and decreasing the air quality inside your home. This improves efficiency, which in turn lowers energy expenses and helps your system work smoothly.

So, keeping the air filter in good condition is crucial and must be taken care of consistently. But how often to change the furnace filter? Read ahead to find out.

Frequency of Changing Furnace Filters

If you want your HVAC system to last as long as possible, keep the air quality high, and keep your energy bills low, you need to change the furnace filter regularly. Several factors, such as the type of filter, the characteristics of your home, and the external climatic conditions, determine the appropriate frequency for replacing your furnace filter. By keeping these things in mind, you can figure out when it’s best to change the filters in your furnace.

Types of Furnace Filters and Their Recommended Change Frequency

Various furnace filters are available, each with its own set of pros and cons in terms of filtering capacity and suggested replacement intervals:

Fiberglass Filters

To protect HVAC systems from large contaminants like dust and lint, the most common and affordable filter type is the fiberglass filter. Particularly in houses with heavy HVAC use, it is advised to replace them every 30 days because of their limited filtration capacities.

Pleated Filters

Better filtration and the ability to trap tiny particles like pollen, mold spores, and pet dander are achieved using pleated filters, which are often made of cotton or polyester folds. While air quality and usage in the home do affect how often you should change your pleated filter, the general rule of thumb is every 90 days.

Electrostatic Filters

Electrostatic filters are able to attract particles due to their self-charging fibers. Both one-time use and long-term (washable) varieties are available. Every three months, replace the disposable electrostatic filter and clean the permanent filter as needed.

HEPA Filters

High-efficiency particulate Air or HEPA air filters are considered the best in the industry since they can capture 99.97% of particles smaller than 0.3 microns. People with severe allergies or those who work in healthcare environments often utilize them. Although they still require routine inspection, you might not have to change them quite as frequently (around once a year) as other varieties.

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Factors Affecting Filter Change Frequency

The frequency of furnace filter changes is dependent on a number of factors

furnace repair cost

Home Size

Filters can become dirty more quickly in larger homes due to increased air circulation. One possible explanation for why filters last longer in smaller houses is because there is less air circulation and the heating system is used less.

Air Quality

Due to the higher concentration of air particles, homes in areas with high levels of pollution or pollen may need to change their filters more regularly, impacting air quality.

HVAC Usage

Changing a dirty furnace filter more frequently is a common practice for systems that are used more often. It is recommended to inspect the filter periodically and, if necessary, change it during seasons when the HVAC system is utilized often.


Fur and dander shed by pets can quickly turn your filters into dirty furnace filters, so it’s a good idea for homes with pets to think about changing their filters more often.


It is essential to keep filters clean in homes where family members have respiratory diseases or allergies. To maintain good indoor air quality and remove airborne dust consistently, you should consider changing them more often.


The air quality can be greatly reduced when smoking indoors, and the increased presence of airborne particles means that filters need to be changed more frequently.

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Seasonal Considerations

The seasons can play a role in determining when to change the furnace filter, as consumption patterns naturally vary:

  • Winter: Filters get clogged up faster in the winter because furnaces run more often to heat homes. Regular checks should be done, and adjustments should be made as necessary.

  • Summer: In the summer, the same rules that apply in the winter also apply if the air conditioner is turned on often. Clean filters are more important when outdoor pollen levels are high since they affect indoor air quality.

  • Spring and Fall: During the spring and fall, HVAC systems may not be used as often, but pollen and other allergens

Advanced Tips for Managing Filter Changes

Rather than relying on predetermined intervals, many newer smart thermostats can be set to remind you to check or replace your filter depending on the amount of time it has been in use. The closer it is to how the system is actually used, the more effective it can be.

Some businesses provide subscription services that will have fresh filters sent to your house at predetermined intervals. In addition to making sure you never run out of the correct size or type of filter, this can serve as a helpful reminder to change it.

Although the time may not have come, your filter may appear unclean indicating that it is time to change it. Do what you think is necessary—regardless of the time of day, replace a filter if it appears blocked.

Furnace Filter Types and Their Lifespans

  • 1-inch filters: Replace every 1-3 months.
  • 2-inch filters: Replace every 1-3 months.
  • 4-inch filters: Replace every 6-9 months.
  • 5-inch filters: Replace every 9-12 months.

Why Should You Keep Changing Your Furnace Filter?

Keeping the furnace filter clean is more than just a nice-to-have—it’s a critical habit that affects your home’s air quality, energy efficiency, and HVAC system’s lifespan. You could risk your family’s health and rack up expensive bills if you put off doing this one little thing.

A clean furnace filter is the most important thing you can do to keep the air inside your home healthy. To keep allergens like dust, pollen, pet dander, and mold spores from recirculating in your home, install a furnace filter.

By minimizing the intensity and frequency of allergy symptoms and respiratory problems, a clean filter can greatly improve the quality of life for families dealing with these conditions.

Your heating, ventilation, and air conditioning system will have to work harder to move air if the filter is unclean or clogged. In addition to increasing power consumption, this could cause the system's components to wear down prematurely due to excessive stress.

To keep your system running efficiently and save money on utility bills, clean the filters regularly. A well-maintained HVAC system efficiently heats and cools your home with less power, which can be a substantial reason in and of itself.

It is wise to get the most out of your current HVAC system because upgrading it might be expensive. To keep your HVAC system running smoothly and protect its components, change the filters regularly.

Maintaining a clean filter is essential to avoid mechanical wear and strain caused by dirt and particle buildup in the system. Reducing the load on your system will increase its longevity and decrease the likelihood of expensive malfunctions.

Steps to Change Furnace Filters

You can find the furnace filter in the air handler of your HVAC system, which might be in the basement, the attic, or even a specific utility closet. The filter may be located close to the blower unit or in the return air duct in certain systems. Find the precise spot where your filter is located before moving forward.

Prioritize safety! In order to avoid the furnace from turning on while you are changing the filter, make sure to turn it off at the thermostat or main power switch. In addition to keeping you safe, this prevents the system from absorbing air that hasn't been filtered.

To reach the filter slot, either open the panel or slide the cover off. Remove the old and dirty filter with care, paying attention to any airflow arrows that point toward the furnace or air handler. Ensure that these arrows point in the same way when you install the new filter.

Look around the filter slot and its surrounding region before you put the new filter in. Use a vacuum cleaner to get rid of any apparent dust or debris. This keeps the airflow clear and prevents performance-reducing obstructions.

Before you install the new filter in your system, make sure it fits by checking its size and MERV rating. Position the replacement filter such that the airflow arrows point in the direction of the blower before sliding it into position. The ideal fit for a filter is for it to slide in smoothly, without any obstructions or spaces around the frame.

After installing the replacement filter, make sure to firmly close the access panel or reattach the cover. To get the most out of your filter, you must be sure that no air can get past it.

Turn on your furnace again by pressing the main switch or the thermostat. It would be helpful to turn the system on for a few minutes to listen for any strange sounds or problems with airflow that could mean the filter isn't installed properly.

Remember to log the date and time when you change your furnace filter. For HVAC systems to function at their best, regular tracking is necessary for keeping to a regular schedule.

Know when to Get Professional Help

If you have never changed a filter before or are confused about which one to use, it could be helpful to talk to an expert from a business like Comfort Union. You can trust that our HVAC specialists will provide you with recommendations based on your unique system and requirements, guiding you toward the best equipment and maintenance practices.

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