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How Often Do You Need to Change an A/C Filter?
General Heating & Air Conditioning

How Often Do You Need to Change an A/C Filter?

Summer is in full swing, and a reliable working air conditioner is not just a good idea. It's also a necessity. And making sure your air conditioner stays in good working condition starts with regular HVAC system maintenance.

At General Heating & Air Conditioning, we help Minnesota homeowners manage their heating and cooling systems so their homes stay cool when they need it. One of the most common questions we encounter relates to how often an air filter should be changed.

We've put together this guide to help you with your household's air filter maintenance plan. Check out this advice, and then give us a call when you need HVAC maintenance for your Twin Cities area home.

Disposable vs. Reusable A/C Filters

While your system will have a specific type of filter requirement, six variations of reusable and disposable styles are available.


HEPA filters have a high-efficiency particulate disposable design and can remove up to 99.97% of particulates.


This disposable option is made from polyester and cotton fabrics engineered to efficiently remove dust and contaminants.


Fiberglass is another disposable model but is also notorious for being cheaper with less protection, so they are not recommended for households that have individuals with respiratory concerns.


Electrostatic uses paper and cotton fibers to create static electricity that traps impurities like a magnet.


UV filter's primary job is to eliminate dangerous viruses and bacteria from the air, but they do not work well for filtering dust or dirt.


The biggest difference between the disposable and washable filters is their price. Washable filters are more expensive and do require some periodic maintenance that will last between five and six years, so there's no need for frequent replacements.

Cleaning your filter only takes a few simple steps:

  • Turn off the HVAC unit.

  • Locate the filter or consult A manufacturer's manual for the location.

  • Clean the filter with the vacuum cleaner, and for washable designs, apply warm water via the faucet head, pushing the dirt out.

  • Give your filter adequate time to dry and place it back in the HVAC unit.

Factors That Determine When to Change Your A/C Filter

It's not uncommon to leave air filters for far too long between changes, but it's not recommended. Anytime air filters become overfull with dust, dirt, and particles; this decreases the efficiency of an air conditioner.

That's why it's important to change your filters regularly. Generally speaking, air filters should be changed about once every three months.

However, the first thing to know about air filters is that there are a number of reasons that can affect the length of time between air filter changes.

Quality of Filter

Higher-end air filters tend to last much longer than discount fiberglass filters. A high-quality filter may be expected to last for up to six months or longer. However, cheaper filters may need to be changed once a month. The air filter's brand and size can also influence how long it should be expected to last.

Size of Home

Smaller homes require fewer air filter changes than larger homes, with a few exceptions. However, if your home uses a smaller air conditioner unit with smaller filters, it may require as many changes as a larger residence would.

Frequency of Use

If you don't use your air conditioner frequently, your filter will last longer. For families that turn off their air conditioner while away from home and at night, your air filter may last for an entire season. However, if you're constantly running your AC, you may need to change your filter more frequently.

Household Pets

Any pet owner can testify that fur gets all over everything in a home. Pet dander and fur can also clog up an air filter rapidly. Pet owners should plan to change their air filters at least every two months. During the summer, when pets are shedding, check your filter more frequently.

Household Air Quality

The air quality inside your home will directly impact your air filter. If you live in an area with poor air quality, you will likely have more particulates inside your home. Likewise, if you use a wood-burning stove or a member of your household smokes or vapes, your air filter will require more frequent changing.  

Checking your air quality can help you stay on top of improving it, and there are several measuring techniques our experts recommend.

  • Indoor Air Quality Testers

This monitor design consists of electrochemical sensors that can simultaneously detect toxins and measure air quality, removing the risk of mold, carbon monoxide, radon, or volatile organic compounds, making it a great option to cover all areas of concern at once.

  • Carbon Monoxide Detector

Carbon monoxide is one of the most hazardous concerns around your air quality because a leak can cause many health issues. The detectors work the same way as smoke detectors and will sound an alarm if there is a leak, so you have ongoing protection.

  • Getting a Mold Test

Mold tests can be completed through air pumps, swab tests, tape strips, and many other options that collect contaminants from various surfaces.

  • Radon Checks

Radon gas develops when rocks and soil break down and leach inside your home, degrading air quality. The tests come in a DIY option, but it is always recommended to hire a professional to ensure accuracy.

Health of Occupants

If anyone in your home suffers from respiratory issues, including asthma or allergies, your filter needs to be changed more frequently. Individuals with compromised immune or respiratory function can be far more sensitive when exposed to airborne particles. Be sure to change your air filter at least once every six weeks if a member of your household falls into this category.

Age-Related Occupant Concerns

If your household includes occupants who may be sensitive to respiratory infections due to age, you should also plan to change your air filter more frequently than is typically recommended. Seniors can be especially sensitive to air particulates. Infants and small children are also more vulnerable to mold, mildew, and pollution.

MERV Rating

The MERV rating is a reporting value that shows the filter's efficiency. It's scaled between one and 20 to help you understand how the filter performs, and the higher the rating, the better quality the filter. The standard rating for most residential HVAC systems is 13, and while there's no set rule on how often to change the filter, the recommendation is around three to six months.

How Can I Tell If It's Time to Change the A/C Filter?

As a good rule of thumb, pick a day to look at your air filter each month and decide if it's time for a fresh one. If your filter appears dirty and you can't see light through the filter, it's time to change.

If your filters require more or less frequent changing, adjust your schedule accordingly.

What Happens if I Don't Change the A/C Filter?

It's not uncommon to be flippant about changing a home's air filter, but any heating and cooling technician can tell you it's a terrible idea to put it off.

These are just some of the problems that can arise when you neglect your air filter:

  • Your home's energy bills will be higher.

  • Your household energy footprint will increase.

  • Air particulates like dust, dirt, and mold are not completely removed from the air inside your home, leading to poor air quality.

  • Ducts can become clogged.

  • The HVAC airflow reduction forces the system to work harder and wear out more quickly.

  • Repairs may be needed more frequently.

Is the Furnace Filter the Same as the A/C Filter?

Your HVAC unit serves multiple jobs, including heating and air conditioning, so some people believe the filters are different for each system. However, this is not true. The same filter is used for both units, so there is no need to purchase individual filters and continue with the recommended schedule of replacements every three to six months.

Call for Minnesota Air Conditioning Service

Besides regularly changing your filters, it's also important to schedule annual maintenance to make sure your air conditioner is in top working condition and prevent future problems. At General Heating & Air Conditioning, our heating and cooling technicians offer regular maintenance programs to help you keep your system cool all summer.

Contact us online or call 952-445-2820 to connect with an air conditioning technician and schedule your next maintenance today.

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