Although it seems like a relatively unimportant component, the air filter is, in reality, one of the most important parts of the entire HVAC system. Many people believe that their air filter works as a filtration system to remove airborne particulates to improve the indoor air quality (IAQ). To a certain extent this is true, but it is not the primary purpose of the air filter even though switching to a HEPA or other higher MERV rated air filter can improve the IAQ. In this article, we will take a closer look at the humble air filter and why it makes good sense to care about this under appreciated component.
What is the Primary Purpose of the HVAC Air Filter?
The main need for an air filter is that it acts as a first line of defense for the components in your HVAC system. Certain components are very sensitive to the dust and debris that can be carried in the air in your home. It’s important to understand that the indoor air will circulate through the air filter multiple times every day. Even the cleanest homes have a certain volume of dust in the air and other pollutants can enter when the doors or windows are opened. Another source of contamination is the material carried into the home on clothes and shoes. The HVAC system represents a significant investment and makes sense to take care of it to ensure that it runs efficiently.
What are the Consequences of a Clogged HVAC Air Filter?
The HVAC system relies on a steady supply of air to work at optimal efficiency. The air in your home passes through the air filters multiple times throughout the day. Depending on the MERV rating, certain sizes of particulates are trapped on the air filter surface. Gradually, the filter membrane will become clogged with material and the airflow will be diminished. The HVAC system needs to work harder to compensate and this creates two serious problems. First, the heating and cooling equipment will be overworked and this increases the chances of a failure and an unexpected repair bill. Second, when the HVAC system is working harder, it will consume more energy and this will increase the utility bill. If this situation continues for a long period of time, it may even lower the expected lifespan of the system leading to an earlier than expected replacement. When you consider the ramifications of ignoring a clogged air filter, it makes sense to change the filter regularly.
What is the Frequency of Air Filter Changes?
As a rule of thumb, it’s a good idea to replace the air filter every 30 days if you’re using replaceable fiberglass filters. The pleated air filters capture more particulates due to their denser nature and they can last up to six months. A basic washable air filter should be cleaned on a monthly basis. These are broad guidelines because we all have different circumstances and there is no one-size-fits-all answer. As an example, one or more pets in the home will produce dander that can clog an air filter faster than normal. If you have pets, you may want to change the air filters twice as often or more. Setting a reminder on your phone or calendar is a great idea and if you cannot remember when the air filter was changed, go ahead and do it now.
It doesn’t take long to examine the air and furnace filters and many people check them every month. If the surface of the filter looks dirty and the membrane cannot be seen, it’s a good idea to clean or replace them anyway. The best way to check is to hold the filter up to a light source to see if you can see any light through the filter. If you can’t, it’s definitely time to make a change.
How Do I Change the Air Filters?
This is a hard question to answer fully because every HVAC system will have a slightly different configuration. The full instructions for an air filter change are detailed in the owner’s manual and you need no special skills or tools to complete the task. The main thing to remember is that the new air filter must match the size and model number in the manual. The number is printed on the rim of the air filter and you cannot use the wrong air filter. Why? Well, if the air filter is too small, it will allow the air to pass around it and the contaminants will enter the HVAC system. Another problem is that the air filter may not fit securely into the filter housing and it will not perform at all.
How Do I Wash an Air Filter?
There are less efficient air filters that can be removed, washed, and replaced. These are inexpensive units, they are less wasteful, but they don’t catch as many particulates. But, if you have a washable air filter, they are easy to clean under running water. The main thing to remember is that you cannot place the air filter back into the filter housing until it’s completely dry. Experts recommend that the air filter is air dried for at least 24 hours to ensure that it is fully dry and clean before it’s replaced. This may seem excessive, but any amount of moisture on the air filter could cause mold growth. Mold releases spores into the air which will have a detrimental effect on the IAQ throughout the entire home. This can trigger asthma attacks and trigger allergic reactions in people sensitive to mold. For this reason, it’s a good idea to have a pair of replaceable air filters on-hand. Then you can use one while the other dries and avoid using the HVAC system without an air filter in place.
Can I Run the HVAC System Without an Air Filter?
Yes, but this is not a good idea because the airborne particulates will damage key components in the HVAC system. This will lead to performance issues and ultimately an expensive repair bill. Purchasing air filters is easy, they can be bought in bulk to save money, and having a few on hand is always a good idea.
If you want to improve the IAQ in your home, contact your local HVAC specialist and ask about air purification options.