The Cold Truth: How Often to Change the AC Filters in Your Home

AC FiltersWhen was the last time you changed your AC filters? According to the PHCC, it's a good idea to replace pleated air filters and furnace filters in your home every 120 days.

If you’re like most Americans, you spend approximately 90 percent of your time indoors.

The indoor air quality of your home is very important since you are breathing it in for the majority of the time.

The only thing more important than your indoor air quality? —maintaining that quality.

This goes beyond dusting and vacuuming frequently. Your home air filters are an integral part of this maintenance, especially if you have pets or children with allergies.

First thing’s first:

Your AC Filters Need to Be Changed

Your AC filters, furnace air filters, and HVAC filters don’t just control the temperature in your home. They are responsible for clean airflow throughout every room in your house and the overall health of the air that you breathe.

One of the most important things you can do for your home is to replace your home air filters regularly. This will keep your air clean, your system intact, and your energy bill low.

So how often do you need to change your air filter?

There are a few factors that go into HVAC filter care that will affect how often you should change your air filter:

The Size of Your Home

If the size of your home is smaller, your air conditioners and furnaces aren’t required to pump as much air to produce a temperature change. This usually means fewer AC filter and furnace air filter changes.

Unless of course your air conditioning units or furnaces are smaller in size to accommodate the smaller space. This would mean that your AC filters and furnace filters will be smaller as well and this case you would have to change them as regularly as the larger systems.

The Location of Your Home

Do you live in the city or the suburbs? Perhaps somewhere in-between? Aside from keeping the temperature in your home comfortable, your HVAC system is also meant to keep your air inside clean and healthy.

Heres the deal —in terms of location you need to consider the quality of the air outside of your home. Cities come with much more pollution and the suburbs come with much more pollen. The “somewhere in-between” could mean humidity, moisture, and mold.

Regardless of the location, poor air quality will result in a shorter life span for your AC filter.

Also, if you have a vacation home that does not get used often, you won’t have to change the AC filters as frequently. But, you should plan to replace them before each visit.

You and Your Family’s Health

Those with allergies or asthma are much more sensitive to airborne particles. HEPA filters are usually recommended for people with these conditions.

If you or someone in your family suffers from allergies or asthma, Then you’ll probably have to change your air filters every six weeks. (HEPA filters last much longer and are used in air purifiers).

If you live in a much more humid climate, the sooner the better. It’s important to keep the quality of your air indoors as clean as possible from mildew and mold spores.

Do You Have Pets?

If you are a dog owner, you know how important it is to keep your home clean to combat all of the shedding. If you’re a cat owner, you know that cats have natural allergens in their fur. Either way, it’s a lot of hair and extra dander.

So if you’re adding pets to the equation, especially with allergies, you’ll need to keep up with changing the air filters every 30 days.

How Often You Use Your Air Conditioning

How often you use your AC system is directly related to the climate that you live in and the seasons that you experience. Remember, the longer your system runs, the more dust, dirt, and debris the air filter will catch.

If you live somewhere that experiences all four seasons, you’ll need to keep up with both your AC filters and furnace air filters, as well as preventative HVAC maintenance.

If you live in a more mild climate, you’ll probably only be running your AC or heat for a few hours a day. If this is the case, your filters may last you all season.

The rule of thumb here is to replace your filters seasonally. Once in the fall, once in the winter, and twice in the spring and twice in the summer. Of course, this depends on the type of air filter you use.

The Type of Air Filter you Use

How often to change an air filter will also depend on the type of air filter you use. Whichever type you choose will depend on your specific needs.

There are a number of air filters out there and they all have MERV ratings. Here are a few different types of air filters on the market today:

Fiberglass Air Filters: These are disposable and the most affordable AC filters. Fiberglass air filters also have the lowest straining capabilities which aren’t the best if you are looking to screen dust and pollutants.

Fiberglass air filters need to be changed every 30 days.

Pleated Air Filters: These are made of polyester or cotton folds. Pleated air filters are much more effective at screening dust and pollutants than fiberglass air filters. The more pleats, the better the filtering performance.

Depending on the quality, pleated air filters need to be changed up to every six months.

Washable Air Filters: Washable air filters are great in theory because you don’t have to replace them. You have to wash and dry them thoroughly. —Emphasis on drying them thoroughly to avoid mold.

Unfortunately, these air filters aren’t as good at effectively filtering out microparticles, pet dander, smoke, bacteria, and viruses. These are better for households with no pets or bad allergies since they only catch large dust particles.

Electrostatic Air Filters: These air filters use an electrostatic charge to attract dust and airborne particles. This keeps debris from floating around your home. There are also re-usable washable options.

However, these filters tend to do a poor job at catching the smaller particles and mold spores. They also need to be replaced every two to six months.

HEPA Air Filters: High-Efficiency Particle Air filters (HEPA) are great for people with allergies or asthma. They are capable of screening 99.97% of debris which is why they are recommended by the US Department of Energy.

These filters come with fine mesh traps that catch all of the pollen, dust and even smoke that come into your home.

HEPA filters work better in air purifiers. While you can purchase them as your AC filters, they won’t work as efficiently due to a lack of fan power. This poses an additional cost, but it’s necessary if you or someone in your family suffers from asthma.

HEPA air filters are pricey, but they don’t need to be replaced for three to five years.

UV Filters: These filters use ultraviolet light to kill bacteria, viruses, mold, and odors in your home. They will work best in conjunction with an HVAC system that is designed for higher static pressure since they won’t screen dust particles or pollen.

Think of them as an air purifier within your ventilation system. These can last up to 12 months.

Keep in mind that the type of filter you choose will depend on where you live, the number of people and pets in your home, and the overall health of you and your family.

How Do I know When it’s Time for a Filter Change?

In case you lose track time and forget when the last time you replaced your air filters was, there are a few ways to tell that it’s time to replace them:

  • Your air filter has become noticeably gray
  • Built up dust is clearly visible on the filter media
  • Your home is more dusty than usual
  • Your heating or cooling system takes longer to cycle than usual
  • Your system will begin to make strange noises
  • You’ll notice an increase in allergy flare-ups or asthma attacks
  • You’ll notice a musty odor

Of course, neglecting your AC filter changes can lead to expensive maintenance on your whole HVAC system. Worst case scenario, you’re system may break down leaving you in the cold or heat.

Some General Recommendations

With all the factors that come into play, the time frame for changing your air filters can get confusing. Here are some general recommendations for changing your AC filters:

6-12 months  for unused vacation homes

4-6 months for single households with no pets

Every 60 days for a single household with pets

Every 90 days for family households with no pets

Every 20 days for a household with multiple pets and/or allergies and asthma

Of course, if you still can’t remember these general recommendations, keep it simple and change your AC filters every month.

Your Indoor Air Quality is Important

Your indoor air quality is as important as the outdoor air quality of where you live. The AC filters you choose are the key to keeping your indoor air healthy.

If you’re in Seattle and have any heating or air conditioning concerns, contact us. We’ll be more than happy to assist you.