How often should you change your return air filter?

Author: Dr. Tanner Waelchi MD  |  Last update: Tuesday, November 11, 2025

Generally, most air filter manufacturers and HVAC companies recommend changing your air filter every 90 days, or 3 months. That can change based on where your home is located (ex. dusty, dry climates), if you have any pets, and the age of your system and equipment.

What will happen if you have a dirty filter in your return air duct?

Reduced airflow

A dirty filter could be to blame. When the air filter is clogged, the airflow in your HVAC system is reduced. This makes it harder for the system to keep your home at a comfortable temperature. This can lead to uneven or inadequate heating and cooling.

Do you really need to change air filters every 3 months?

Changing your filters every 3 months is the way to maintain proper airflow, efficient operation, and great indoor air quality throughout your home.

Should you put filters in your return vents?

Putting filters in air return vents is generally not recommended for several reasons: Airflow Restriction: Return vents are designed to allow air to flow back to the HVAC system. Adding filters can restrict airflow, leading to reduced efficiency and potential strain on the system.

How often should I change my return air filter?

How Often Do I Need to Change Out My Air Filter? Generally, most air filter manufacturers and HVAC companies recommend changing your air filter every 90 days, or 3 months. That can change based on where your home is located (ex. dusty, dry climates), if you have any pets, and the age of your system and equipment.

How Often Should I Change My Home's HVAC Air Filter?

How do I keep my return air vent clean?

Use your vacuum cleaner's hose attachment to clean the return's interior and surrounding areas. Then use a soft-bristled brush to clean the grille thoroughly. Wipe down the grille with your microfiber cloth and cleaning solution before reinstalling.

How many air filters should be in an HVAC return duct?

You need 1 “set” of filters, 1 filters air intake to the blower unit & 1 on the return to filter house air.

How many return vents should a house have?

Instead, there should be at least one return vent in every room, with two or three being ideal. If your house has only one return vent, this is not a problem — make sure to keep the doors open in every room so the air can circulate properly. Make sure there are no furniture, draperies, rugs, etc. blocking return vents.

What can I put in my vents to prevent dust?

Inexpensive, washable vent filters may offer an improvement. However, stubborn dust issues may benefit from the addition of a HEPA air filter.

What happens if you wait too long to change the air filter?

You may notice a significant decline in HVAC performance, increased energy bills, and decreased comfort in your home. Additionally, delaying filter changes can lead to more extensive damage to your HVAC system, requiring costly repairs or replacement.

What is a good MERV rating for a carrier?

A good MERV (Minimum Efficiency Reporting Value) rating for residential HVAC systems is typically between 8 and 13. MERV 8 filters capture basic particles like dust, pollen, and pet dander and are adequate for most households.

How to tell if a HVAC filter needs changing?

' Hang a clean white sheet a few inches away from an air vent for a few minutes. If the sheet turns gray, the air filter is dirty and it's time to replace it. Keep in mind that dust around the air vents may also indicate a clog in the ducts.

Why is my return air vent so dusty?

The return air vent pulls air from inside the home to recycle in the HVAC system. Pet fur and dander, smoke, and other indoor pollutants leave dirt on the vents. Old air filters need changing regularly to prevent dirty return air vents. A pro should clean your HVAC system at least every three to five years.

Can you run AC without a filter?

The short answer: You can get away with running your AC without a filter for a short period of time. However, doing so for longer than 6-8 hours can hurt your system and decrease your home's indoor air quality.

What if I put my furnace filter in backwards?

The most common problem you will face with a backwards facing filter is simple inefficiency. If your furnace is forced to blow air through the non-porous end of a filter, it will take more energy to do so. The blower will be overworked and you will pay more money for your heating.

How many returns should a 1500 sq ft house have?

However, most HVAC contractors use a rule of thumb to determine the number of air vents needed. For example, for a standard residential HVAC unit, you'll generally need one supply vent and one return vent for every 100 to 150 square feet of living space.

What are the symptoms of not enough return air?

Symptoms include weak airflow and uneven cooling or heating throughout your home, with some rooms feeling much cooler or warmer than others. Homeowners should regularly check vents for consistent airflow. If you notice a significant drop in air pressure or uneven temperatures, it could indicate return air issues.

Should I close return vents in winter?

Conversely, in the Winter heating season, you will want to pull the coldest air back to the furnace to be warmed and create circulation. In these months, you'll want the lower air return open and the upper air return closed.

What room should return air ducts not be installed?

What room should return air ducts not be installed? Return air ducts should generally not be installed in rooms with high humidity or areas prone to moisture accumulation, such as bathrooms or kitchens.

Can I put filters on my return air vents?

While return vents don't always require filters, adding them provides additional filtration, improving indoor air quality and keeping dirt and debris out of your system.

How many air purifiers should a house have?

Air doesn't circulate as well up and down stairs, so you will want to put at least one air purifier on each floor. If you have multiple floors, treat each floor as its own section and divide the square footage by 700 to get the number of air purifiers per level.

Do return ducts need to be cleaned?

cleaned simply because it seems logical that air ducts will get dirty over time and should be occasionally cleaned. Provided that the cleaning is done properly, no evidence suggests that such cleaning would be detrimental. EPA does not recommend that the air ducts be cleaned routinely, but only as needed.

What happens if you block a return air vent?

Blocking the return air supply to the air handler or blower compartment reduces the amount of air that flows easily into the system. The fan's speed won't slow any more when you close off the returns, and it creates positive air pressure.

How to clean a return air filter?

You Can Clean Your Air Conditioning Filter in 7 Easy Steps:
  1. Undo the hinged Return Air Grill frame fixing. ...
  2. Swing the frame open and let it hang vertically.
  3. Slide out the filter.
  4. Vacuum the lint off the filter.
  5. Wash the filter in warm water.
  6. Let the filter completely dry out in the sun.

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