How Often Should You Change the Air Filter In Your House?


In the HVAC system of your house, the air passes to the ducts through the air filter. This air filter purifies the air from air pollutants, impurities, and other contaminants.

The debris and dust particles get trapped in the air filter, and the process of ventilation is carried out efficiently. But the question is, how often should this filter be changed? The regularity of changing the air filters depends on the air filter model, indoor air quality, size of the house, and air pollution level. Most manufacturers recommend to replace the air filter after every 30-90 days, or up to 60 days in a home with. If anyone from the house has an allergy, then a regular filter should be replaced after every 20-30 days.

The air filter should be changed properly on time, but most people don’t know how to change them. They are also unaware of the side effects of a dirty air filter. Let’s discuss in detail.


How Often Should I Change the Air Filter?

For appropriate ventilation of the house, proper air filter maintenance is necessary as the air pollutants can affect the residents’ health and be harmful to the HVAC system. Many factors can change the number of days after which the air filter should be changed.


Effect of Pets

Pets in the house can affect the number of days after which the air filters should be changed as the pets’ fur and dander moves freely in the air and gets clogged in the air filter.

The experts recommend changing the air filter after every two months if you have one pet at home. With more than one pet, it is recommended to change the filter after every thirty days.


Allergies and Asthma

The air pollutants and mold present in the air can trigger various allergies like cough, runny nose, eye irritation, and itching. People with severe allergy problems prefer to change the air filters after every fifteen to twenty days. People with minor allergies replace their filters mostly after one month.


Home Being Vacant

The houses which are not used very often, like vacation houses, stay clean for long. Due to the less polluted air, the filters don’t get dirty very often and can be replaced every six months to one year.

Similarly, in a house with only one person living without pets, the air filters can be changed after four to six months.


Size of the House

The size of the house and the number of people living in the house cause the air filter to become dirty more quickly. In a large house, the air filter should be checked every month to maintain the house’s ventilation system. 

This proper maintenance will also make the HVAC work more efficiently, and the energy usage will also minimize, reducing the cost of energy.


Type of Filter Used and Its Effect on Airflow

We’ve raved in our blog often just how much we love air filters with high MERV ratings. MERV ratings are a measure of an air filter’s ability to filter out particles compared to the ability of the air conditioning unit to maintain airflow.

Filters with high MERV ratings don’t just filter the large things like debris like your average fiberglass filter would, but they can also filter out smaller pollutants to help your health. Finding the right balance between air filter type and airflow is crucial, however.

Not everyone’s home is equipped with an air conditioning unit that can handle medical-grade air filters. If you try a filter that’s too specialized, you may soon find that it needs to be replaced much more frequently and that your electricity costs have gone up because of a blocked airflow.

We find that MERV-11-rated filters work best in the average home.


How Do I Change the Air Filter?

Changing the air filter of your house is not very difficult if one follows proper steps at the time of replacement.


  • Turn the Unit Off

The first step in changing the air filter is to turn the unit off by flipping the switch on the thermostat. Or else the system can be completely turned off at the circuit breaker.

  • Locate the Air Filter

The air filters are located on the wall or ceiling, from where the air is drawn back to the system from your home. If the filters are not located there, they must be in a utility closet, basement, or attic.

  • Remove the Grille

There are two ways through which the grills can be removed. If the filter is in the system air handler, it will require a screwdriver to open. But if the grill covers the filter with a tab, it can be removed without screwdrivers.

  • Identify Right Filter Size

To replace the air filter, it is necessary to identify the right size of the air filter already being used. It is mostly printed on one side of the filter, but if you cannot identify the right size, you can take a measuring tape and measure its length, width, and depth.

  • Remove the Dirty Filter and Insert a New One

Remove the dirty filter from its place and inspect how it was already placed inside. Also, check for unusual dirt, which shows the signs to replace it more frequently. Place the new filter and make sure its airflow arrows are pointed into the unit. After this, cover the filter with the grill.

  • Turn the System Back on

Turn the system on and ensure that the air conditioner is running smoothly. Moreover, mark the date on the calendar so that the next filter can be changed periodically.


Why Change the Air Filter?

Changing the air filter of your HVAC system from time to time is essential to increase its efficiency. Proper maintenance of your heating and cooling system makes it effective in working, and it provides better air quality with an increased life span of the system. Moreover, it consumes less energy, resulting in low electricity bills.

Changing the air filter at a proper time can be beneficial in the following ways.


  • Boosts Air Quality

The air filter’s main purpose is to purify the air from all the pollutants, dirt, debris, and mold. The particles present in the air which are not naked to the eye can be very dangerous for health.

If there are pets in the house, it is recommended to change the air filters more often. Air filters are white, and if there is a layer of dirt on them, it means that they haven’t been changed in a while and can be harmful.

  • Reduces Electricity Bills

A clogged filter causes the system to work longer than usual to pull the air through to make the room cool or hot. This overwork of the HVAC system increases electricity costs. Therefore, it is recommended to change the air filters after a month in intense warm or cold weather.

  • Prevents HVAC System Failure

The clogged filter not only increases the cost of electricity but also damages the HVAC system. Due to continuous working, the system can heat up and break, which can be expensive to repair or replace. Changing the air filters on time can eliminate this risk.


Related Questions

How can I tell if the air filter needs changing?

There are many signs through which you get to know if the air filter of your HVAC system is dirty and needs changing. For example, if you see more dust particles in the air and find it difficult to breathe. It means that the air filter needs to be replaced.

Moreover, people with allergies suffer from allergy attacks as the dust particles remain in the air. Another sign of dirty filters is that your unit becomes warm, and electricity cost increases.


Can I run my HVAC system without an air filter?

An air conditioner can work without the air filter, but you should refrain from doing this as leaving the air conditioner will result in penetration of the dirt and air pollutants in the system, which can damage your HVAC system and lead to expensive repairs.


Why is it important to have a good air filter?

A good air filter improves the air quality more efficiently than a standard air filter. It reduces the contaminants along with the pollutants and allergies present in the air.

Moreover, a good quality air filter keeps the heating and cooling process going for a long time without the risk of breakdown. It not only reduces the risk of repair but also reduces the air cost.


How are HVAC filters made?

Air filters are made up of spun fiberglass material, pleated paper, or a cloth enclosed on a cardboard frame.

The fiberglass air filter is inexpensive compared to the pleated air filter, but the quality of the pleated filter is better than the fiberglass filter as it catches more debris.

Moreover, the material of fiberglass filters is not recyclable, but pleated air filters can be recycled.