Replacing Air Filters Keeps Your IAQ High and Your HVAC System Efficient

Published on: December 23, 2013

You’ve heard that you’re supposed to change your forced-air HVAC system’s air filter every month, but do you know why? Your air filter actually has a huge impact on your heating and air conditioning system’s efficiency. Often, it’s the only thing cleaning pollutants out of your home’s air. Here’s everything you need to know about replacing air filters and why you should make it part of your home maintenance checklist.

Why Regularly Replacing Air Filters Is Important

Virtually all the air in your home will pass through the air filter that’s working with your furnace, A/C or heat pump, bringing dust, pollutants from cooking and cleaning, and other contaminants with it. This is good because these are exactly what your air filter is designed to trap so the air returning to your home is clean. However, if you aren’t replacing your air filter regularly, it can become full of these pollutants and lead to the following problems:

  • Reduced airflow, making your HVAC system work harder to cool or heat your home
  • Burned-out motors or other parts due to this extra work
  • Airflow so low that your A/C freezes
  • Increased energy bills because your HVAC system is running longer
  • Poor indoor air quality that triggers allergies or asthma or just makes a home dustier

Types of Air Filters

When replacing air filters, you should be aware that each type of HVAC system requires a slightly different type of filter. Air filters vary in size and shape based on where they are placed in the system. This information is usually marked on the old filter for reference or can be found in the HVAC equipment’s owner’s manual.

The big choice to make is what kind of efficiency you want. When replacing air filters, efficiency is another way of saying what size particulates your air filter filters out. To help you understand all the manufacturers’ claims and different technologies available, each air filter is given a MERV rating. MERV stands for Minimum Efficiency Reporting Value.

The MERV rating measures how small the particulates that a specific air filter will remove from your air. For residential filters, the MERV scale usually runs from 1-16, with the low numbers only capturing the largest particles. The smaller the particles a filter will capture, the more particles it will capture. MERV 16 will capture the most. Alas, high MERV filters – 14-16 – are rarely used in homes. They’re so dense that they’ll impede system airflow, something you don’t want to happen. While MERV 1-4 filters will capture enough of the larger particles to keep equipment components clean, they won’t do anything for our indoor air quality. An ideal medium between maintaining airflow and keeping your indoor air clean occurs with pleated filters in the MERV 7-12 range.

As stated, simply choosing the highest MERV rating isn’t usually the best option, unless you’re willing to pay to have your equipment modified to handle the higher-efficiency filter. You should always consult your owner’s manual before replacing air filters to see what MERV rating range your system is equipped to handle.

How to Change Your Air Filter

When replacing air filters, remembering when to do it is half the battle. When you replace one, write down the date it will be due to be replaced on a calendar or other place you regularly check. Some homeowners will inspect their filter monthly and then change it based on how dirty it looks. If you can’t see a light shining on the other side of the filter, it needs to be changed.

Finding the air filter for the first time can be tricky. Often, it will be inserted directly into your indoor air handler, especially in smaller systems. However, it could also be located in an intake vent or inside attic return ducts, and in these cases there may be more than one. Always check with your owner’s manual or an HVAC professional if you think there might be more than one filter.

Actually replacing air filters is easy once you’ve found them. You simply pull out the old one and slide the new one in, making sure the arrow on the filter is pointed toward your air handler or blower. Sometimes there’s a door to open or vent to unscrew, but that is the most complex the job will get.

Savings From Regularly Replacing Air Filters

Regularly replacing air filters may increase the amount you spend on filters, but it will likely reduce your overall HVAC expenses because you get the combined benefits of lower energy bills, fewer repairs and a longer-lasting system. In addition, you’ll be able to say you’re reducing your carbon footprint and helping make the world a greener place.

For more ways to improve your HVAC system’s efficiency, contact us to find an HVAC contractor near you. We’re happy to discuss more ways you can lower your heating and cooling bills.