You Need To Replace Your AC Filter — Do You Know How?

Air filters quickly become clogged with debris, especially in the cooling season when air conditioners are running around the clock. Failing to change your filter can mean you’ll be facing a repair, higher energy bills, and decreased life span from the AC. In other words, replacing your AC filter is one of the easiest ways to ensure optimal system performance year after year.

The good news is that swapping out your air conditioner filter is a simple task — if you know what you’re doing.

How To Replace Your AC Filter: An Easy Step-by-Step Guide

In many homes, the air filter is near the thermostat. So, the first step is to locate the filter. Go to your thermostat, and look for a vent. If you can’t find a return vent with the filter close by, look at the air conditioning unit. Some models house the air filter closer to the system rather than at the return air grille.

Here are the next steps once you’ve located the filter:

• Loosen the fasteners holding the front of the grille to the vent, and gently remove the cover. Set it aside. The air filter should be directly behind the cover.
• Reach in and pull it out.
• Set the filter to the side, and assess its condition. When it’s past its prime, a dirty filter will usually be a dingy, grayish-brown color.
• If the filter is dirty, grab the new air filter.
• Identify the arrow pattern on the edge of the filter. The arrows should not point out or at you.
• Once you find the arrows, position them to face the wall.
• Place the air filter back into the return duct opening, gently easing the bottom portion of the filter in first and then the top.
• Double-check that the arrows are pointing toward the duct.
• Give the filter a gentle pat to ensure it fits snugly into the opening.
• Put the cover back on.
• Tighten the fasteners.

Now, the job of changing the air filter is complete. Replacing a clogged or dirty filter can help your home feel more comfortable because air flows freely through your system.

What’s the Best Type of Filter To Use?

Not all filters are the same. There is a range of different filter types and efficiencies available. The minimum efficiency reporting value (MERV) is a rating that tells you how efficient a particular filter is at cleaning the air.

Residential air filters usually have a MERV between 1 and 12, with higher numbers indicating filters are more efficient at removing dust, particles, and bacteria from the air.

Here’s a general breakdown of the different categories of MERV ratings for home air filters and what they mean:

• 1 to 4 means minimal filtration, with less than 20% of air particulates being removed.
• 5 to 8 offers better filtration, removing between 20% and 35% of air particulates.
• 9 to 12 offers the best filtration, removing at least 50% and potentially more than 90% of air particulates.

If you’re not sure what type of air filter is best for your system, contact an HVAC professional. There can be risks associated with installing a filter that’s not designed for your HVAC system.

How Often Should You Replace the Air Filter?

For most homeowners, it’s helpful to change the filter every three months or so. You should change it more frequently if:

• You have pets that shed.
• Your home sees a lot of traffic.
• You’re remodeling your home.
• Anyone in your home suffers from allergies.
• Your home gets especially dusty for any reason.

It’s also a good idea to check your filter every month and change it out when it appears dirty and when the summer season heats up and you use your AC more often.

Air Filter Replacement FAQs

How bad is it if I don’t change my filter?

If your HVAC air filter is only moderately dirty, failing to change it can reduce the efficiency of your heating and/or air conditioning system, leading to higher utility costs. If the air filter is not just dirty but partially or fully clogged, it can damage other parts of your HVAC system. By reducing airflow, a clogged filter can force the AC compressor to work harder, overheating it, or in the winter, it can cause the heat exchanger in your furnace to overheat and crack.

Shouldn’t I choose the filter with the highest MERV value?

Not necessarily. Many HVAC systems were designed to use basic fiberglass or pleated filters with low MERV ratings. Some may accept air filters with higher ratings, but if you go too high, you may introduce an airflow restriction that reduces efficiency as much as a dirty air filter does.

What’s in my air that makes the filter turn brown?

In most cases, the brown accumulations on an HVAC filter are simply household dust, pollen, pet dander, pet hair, and other airborne particles the filter is designed to remove. If your air filter turns black, however, it can be caused by candle smoke or more harmful sources like soot from a water heater or black mold.