How Often Should You Change Your Furnace Filter in a Year?

Filters are an integral part of a furnace. A furnace filter’s main function is to filter out dust, dirt, allergens, and other particles from the air. Therefore, it’s crucial to change your furnace filter on a regular basis. However, the question remains to ponder: how often should you change your furnace filter?

In this article, the experts at River Valley will help you understand what factors affect the life of a furnace filter and how often you may need to change it. So, make sure you scroll down to the end. 

How often should you replace your furnace filter in a year? 

Unfortunately, there is no thumb rule to determine a particular interval to decide when to replace a furnace filter. Several factors are at play when determining if a furnace filter requires replacement. However, most experts recommend changing filters every few months to at least once a year, depending on the type of filter you are using. 

You also have to remember all HVAC systems operate differently. Therefore, when it comes to changing furnace filters, it becomes essential to know what type of system you have and how often its filter needs replacing before beginning any repair work. 

Also, always ensure you use the correct size filter suitable for your furnace model. An incorrectly sized/ rated filter can also result in poor performance and may cause unwanted stress on your entire HVAC unit.

Factors affecting the frequency of furnace filter replacement

You must consider several factors that affect the lifespan of a furnace filter when deciding the ideal time interval to replace it. So, here are the factors that can affect the life of a furnace filter and require you to replace it.

Type of filter used

The frequency of filter replacement will mostly depend on the type of filter installed in your furnace, its size, and its efficiency rating. For example, smaller 1-2 inch thick filters with lower MERV (Minimum Efficiency Reporting Values) ratings usually require more frequent replacement than larger 5-6 inch thick filters with higher MERV ratings. 

Most filter manufacturers also mention the recommended intervals when it might need a replacement on their packaging. Moreover, experts suggest changing 1-2 inches thick standard filtering material every 1-3 months, 3-4 inch filters every 6-9 months, and 5-6 inch thick filters every 9 -12 months. 

Occupants in the house

The frequency of changing your filter also depends on the number of residents. If you have a small family, replacing your furnace filter every 4-6 months may suffice. However, homes with more people will require the replacement of furnace filters sooner than usual as more people means more air to clean for the filter.

Pets in the house

If you have any furry friends at home, remember that the furnace filter will have to deal with their fur as well. The animals often shred lots of hair, which can easily clog up a regular rated filter quickly, requiring frequent replacement. It will directly affect how often you need to change your furnace filter. 

Therefore, experts suggest investing in a high-quality HEPA (high-efficiency particulate air) filter, which offers better filtration and lasts much longer. As a result, fewer replacements are needed throughout the year.  

Location of furnace

Another factor affecting how often a furnace should be changed is its location. Furnaces installed near windows or in areas with dust and dirt will require more frequent filter changes than those in less dusty spots. 


If any member of the household suffers from allergies, you must replace your furnace filters more often. Allergen-trapping systems such as HEPA filters can be very effective at trapping airborne particles that may worsen symptoms for those affected by asthma or allergies. 

However, this also means you should take optimum care in replacing the filters to ensure their highest efficiency in blocking any allergy-causing elements. As per expert recommendations, you must change your furnace filter every few months to ensure you don’t suffer from allergies.

Usage of furnace

The usage frequency of your furnace also needs to be considered when replacing its filter. If you use the heating system more often (such as during winter), you will likely need to change your filter more frequently than someone who lives in a warmer place and rarely uses the furnace.

How to tell if your furnace filter needs replacement

If you’re unsure when to replace your furnace filter, a few signs tell you it may be the time. 

Higher than normal energy bills

It is one of the first signs that your filter is clogged and no longer functioning properly as it should. The excess dirt restricts airflow, forcing your heating system to work harder at distributing heat throughout the house, resulting in higher power consumption and increased utility costs. 

Inadequate airflow from vents

If you feel less air flowing through the vents than usual, it could be because of a dirty or worn-out furnace filter blocking airflow within the unit. It’s best to check and change filters regularly, so they don’t get too full over time. 

Unusual smells coming from the vent

Musty odors can indicate an old or dirty filter that might need replacing. In some cases, however, such unusual odors can point to more serious problems with your HVAC system. You should immediately call an expert for repairs before any major damage occurs! 

Dust accumulation

If dust is collecting faster than usual on surfaces in your house, your filter might be torn out. It can be a sign that the filter needs replacement.

Get a River Valley HVAC expert to fix your furnace!

Replacing a furnace filter is an easy and quick task you can carry out independently. However, if you are still unsure of the process, the best bet is to call a professional from a reputed HVAC company like River Valley.

The professionals at River Valley have tons of experience installing, overhauling, and repairing all kinds of HVAC equipment. Whether a furnace filter replacement or an overhaul, River Valley HVAC technicians will provide you with a proper and prompt solution to the problem. So, book your appointment with a River Valley HVAC technician now and have your furnace fixed in no time.