changing dirty HVAC filter

A Step-by-Step Guide on How to Change HVAC Filters

A Step-by-Step Guide on How to Change HVAC Filters

No one wants to see their air conditioner quit in the dead of summer. Thankfully, when your HVAC system doesn't seem to be pumping out the massive quantity of frigid air it used to, you should not assume the worst. Sometimes you just need a filter change.

HVAC filters have an important purpose, and when you do not take the time to maintain them, the consequence can change your world.

What HVAC Filters Do

Essentially, HVAC filters keep your house clean and your HVAC system running efficiently. They do what filters do by filtering dirt and particles from the air that runs through them.

An efficient HVAC filter will keep the indoor system parts from clogging with dusty and other foreign material that hangs in your air. They also keep the air moving through the HVAC machine.

A clogged filter can cause reduced airflow and systematically increase your power bill when your system works harder than it should, so you need to keep an eye on this small but important part of your system.

Types of HVAC Filters

Not all HVAC filters are made alike. To understand how to change your HVAC filter, you must understand first what type of filter you have.

Mechanical Filter

Mechanical filters come in two varieties: charcoal and fiberglass. Fiberglass filters come in one and two-inch thicknesses. Fiberglass filters cost less than other filters but also do the least amount of work.

Charcoal filters will cost you more but will catch more particles and keep your air cleaner. If you have a mechanical filter, plan on changing it at least once a month.

pleated HVAC air filter


A good pleated HVAC filter will trap between 35 and 40 percent of indoor air pollutants. The effectiveness of a pleated filter depends on the amount of fiber per square inch in each filter. The more fibers a filter has, the more particles the filter can trap.

You should plan on changing your pleated filter every 45 days.

High-Efficiency Pleated Filters

Pleated filters have a special subcategory of high-efficiency pleated filters. These 4" and 5" pleated filters have a separate cabinet between the furnace and return box, and they are the most common type of filter.

A high-efficiency pleated filter will filter over 90 percent of the dust going through the filter, making it extremely efficient. This filter also requires less maintenance, so you need only replace them once a year.

Electronic or Electrostatic

The electronic or electrostatic is the most expensive type of filter, but it's also the most effective type of filter in that it relies on electricity to trap small particles.

Change your electronic or electrostatic filter every three months.

How to Change Your HVAC Filter

You can best identify the type of manual you need to start with your HVAC manual. Determine the type of filter you will need and also the location of your system's filter. If you do not have a manual, you can often locate a manual online.

Then, follow these steps to change your HVAC filter:

Step one: Turn off your HVAC system.

You do not want the air moving while you take a filter out and put a filter in.

changing hvac filterStep Two: Find the filter.

Use your manual to locate it.

AC filters are located in one of a handful of places. Your filter may be under the grille of the oversized return-air register on the wall if the HVAC system is in the air-handler cabinet.

If you have an up-flow or horizontal systems in the basement or attic, then you most likely have a small, 1" filter rack. You can typically find this filter under the removable door outside the furnace between the furnace wall and air distribution box (also known as the plenum box).

Step Three: Remove the screws.

To get to your filter, you will need to remove the screws holding the lid or the filter on. Put the screws in a visible place so you do not lose them.

If you have a cover, begin by removing the cover and then cleaning the cover before you even change the filter. Dust, vacuum, or wash it off. Make sure you clean the debris from every slot and crevice.

Step Four: Remove the dirty filter.

Bring a large trash bag with you when you change your filter. You do not want to drag a filthy filter through your house.

If you have a washable filter with you, put the filter in the trash bag and then take it outside where you can hose it off.

Step Five: Check the arrows on the new filter.

Make sure you're putting your filter in the correct way. If you put the filter in backward, it will not stop dirty and gunk from entering your system and your air.

Look at the arrows on the filter and use them as a guide to put the filter correctly. If your filter has a place to write the date, then write the date you installed the filter.

Then slide the filter into its slot, replace the lid, and screw it back on, if that applies.

Basic FAQs About HVAC Filter Maintenance

Regardless of the filter, you should plan on checking it monthly. T his will prevent a dirty filter from creeping up on you. Put an alarm on your phone to remind you to do this, since a clogged filter can put unnecessary stress on your HVAC system and even cause illness in your household.

Several things can affect your filter.

st louis skyline

Where Do You Live?

Think about your home environment and outside terrain as you consider how often to change your filter.

for example, if you live on a dirt or gravel road, you will find yourself needing to change your filter more often. If your area has construction going on nearby, you will find yourself with more dirt in the air and the need for a more frequent filter change.

If you live in an area with high humidity, you may not have more dirt in your filter, but your filter will be more prone to mold spores and mildew. If your filter gets moldy, then your HVAC system will distribute those spores throughout your home and poison its residents.

Plan on changing your filter frequently if your environment deems the action necessary.

If you have pets, you will also need to change your filter more frequently. Pet hair can clog the filter quickly and compromise your HVAC's system's efficiency.

How Often Do You Run Your HVAC System?

If you live in a warm or extremely cold area, you will run your system more than if you lived in a temperate area. Some areas of the world, like Southern California, have such temperate weather that individuals do not always have air conditioning.

woman blowing nose from allergies

Do You Have Allergies?

If you're prone to breathing problems or if the residents of your home have allergies, you will need to change your filter more frequently. If you need cleaner air because of allergy problems or breathing problems, you need a clean filter. Individuals with COPD or emphysema are especially ta risk.

Do You Smoke?

Tobacco smoke puts extra stress on HVAC filters. It causes them to clog more quickly when the filter becomes sticky from tobacco residue. The stickiness prevents a filter from doing its job effectively.

What Type of Filter Do You Have?

When you shop for an HVAC filter at your local hardware store, you may find yourself with innumerable choices and prices. Cheap prices often mean cheap filters, so keep in mind how often you'll have to buy a filter if you are saving money on a cheap one.

Expensive filters have higher-quality fibers and thus do not need changing as often.

Signs You Need to Change the Filter

As you check your filter monthly, know what you're looking for. If you pull out a visibly dirty filter with pet hair all over it or if the filter has an odd color, change the filter. If you see mold growing on the filter, change it.

If you notice your HVAC system isn't doing its job as efficiently as in the past, do not begin to picture the worst, the thousands of dollars you will need for a new system.

You may just need a new filter, and that costs pennies compared to a new HVAC system. Begin by changing your filter, and then monitor your system.

Also, if you notice an increase in allergy symptoms or upper respiratory problems across the board among your home's residents, perhaps you need to change your filter. A dirty filter can cause unexplained illnesses.

If you live in an especially humid area, you're more prone to mold-related illnesses, so keep your HVAC filter clean to prevent lung and general breathing problems.

In addition to changing your filter, you should have your HVAC system checked regularly. Have it professionally maintained annually to make sure small problems do not turn into big problems that cost you more than what you'd spend on a filter.

Breathe Easy with a Clean Filter

Once you know how to find, check, and change HVAC filters, you can breathe easy. For all of your HVAC needs, you can count on us - just call!

HVAC Coupons

Looking for HVAC coupons to save on your next A/C unit or even furnace?

HVAC Maintenance Plan

Want two preventative maintenance visits per year AND VIP treatment on any repair service?

Count on The Best - Crystal Heating & Cooling