How Often You Should Change Your Air Filter

When to replace your HVAC air filter

Generally, air filters should be changed every 30-90 days.

Visually inspect your air filters monthly to determine when they need to be replaced with a new, clean filter.

The general rule is 30-90 days, but the frequency of how often to swap our your air filters can vary based on a few factors:

Type of air filter: Higher quality air filters, like those that are pleated, last longer than the more affordable alternatives, like fiberglass filters.
If you have pets: If you have cats or dogs or both, you will want to change your air filter more often than someone who owns fish. Pet hair clogs filters faster.
If you have allergies, asthma, or other lung-related complications: To make breathing easier and to reduce any allergy symptoms, you’ll want to change the filter more frequently.
If you have children: Changing the air filter more often can help keep your kids healthy – this is especially true for infants and toddlers.
Size of your home: Larger homes filter more air than smaller homes, and therefore require air filter replacements more.
Current season: During spring and fall, your HVAC system runs less often, so there is less air being pushed through. This reduces the need to replace the air filter at those times.

Factors That Impact Air Filter Replacement	Description
Air Filter Type	High quality air filters last longer
Pets	Pet hair clogs air filters faster
Allergies or Asthma	Those suffering from lung-related complications should replace more often
Children	Changing filters more often keeps kids healthier
Home Size	Larger homes filter more air than smaller homes
Season	HVAC is used less often during times of mild weather

Signs it is time to replace your air filter

If it has been a long time since you changed your air filter, you may be able to notice these signs:

Weaker airflow from vents
System has to run longer to achieve thermostat settings
You notice more dust around your home than normal
Increased noise from your HVAC system as it strains to run

By watching out for these common signs, you can catch issues with air filters and your HVAC systems sooner.

Why should you replace your air filter?

Changing your air filter regularly is beneficial to your health, helps reduce your electricity bill, and helps prevent a complete HVAC system failure.

Health Benefits: Every time you breathe in, you’re not just inhaling oxygen – you’re also bringing dust particles, allergens, and other potential contaminants into your lungs. When air filters are dirty and clogged, they can no longer effectively capture these bad air actors. This decreases the air quality within your home.
Lower Electricity Bills: Clogged air filters can increase the energy consumption of an air conditioning system by 15%. During the summer, this can be a real pain to your wallet when the energy bill comes each month. Especially in Texas!
Avoid Complete HVAC Failure: When you leave a dirty filter in for too long, you are causing your HVAC system to work overtime. The harder your system works, the shorter its lifespan. If you want to prolong your heating and cooling system’s life, change the filters often.

What is the best air filter?

The best air filters are pleated and have high MERV ratings. Make sure to check that you are buying the correct size air filter as different systems require different dimensions.

What is a MERV rating?

MERV stands for Minimum Efficiency Reporting Value.

A MERV rating measures the effectiveness of an air filter at removing particles and contaminants from the air.

The scale measures air filters from 1-20, with 20 representing the best value. Look for a filter that has a MERV rating of at least 8-10.

How to change an air filter

Changing an air filter is simple! Follow these steps to replace your dirty air filter:

Switch off your air-conditioning system.
Locate your air filter.
Take out the filter. You shouldn’t require any tools to remove the filter. Most filters simply slide and in out of the HVAC unit.
Inspect the filter and determine if it should be replaced. If the filter is white, then it can stay in the system. If it has turned gray and there are visible layers of dust or pet hair, it’s time to remove that filter.
Get the correct replacement filter. The size is usually printed on the filter. Take a photo to remember the size for future purchases. While you’re at it, purchase a few extra filters to have on hand.
Install the new filter. You’re all set! We recommend setting an alert on your smartphone so you remember to check again in 30 days.

Written by Graham Lumley

Graham Lumley is Growth Product Manager at BKV Energy, a retail electricity provider in Texas' deregulated market, where he has worked since 2023. He analyzes customer usage and billing data, helps develop BKV's fixed-rate plans, and creates tools to simplify Texas electricity shopping. He has written over 200 articles on Texas electricity rates, delivery charges, plan types, energy generation, and more to help Texans understand their bills and pay less. With over 10 years of experience in consumer, marketing, and energy, he explains the Texas electricity market in plain language.