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Guide: How Often You Should Change You Air Filters

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Surprisingly, one of the best ways to care for your HVAC system is regular air filter replacement. Dirty air filters are a major culprit in HVAC malfunctions and can cause damage over time. Dirty air filters also increase energy bills and destroy the air quality in your home. 

When was the last time you changed your air filter? If you can’t remember, you’re not alone. It is an easily forgotten task by many. Most homeowners aren’t HVAC experts. How often should you change your air filters and furnace filters? 

Every home is different, but the professionals at Cardinal have compiled a guide to how often you should change your air filters. Read below to learn more.

How Do Air Filters Work?

Air filters are much like coffee filters or pool filters, except they preserve the air quality of your home and keep pollutants out of the HVAC components. They sit in a return air duct and block contaminants such as dirt, lint, hair, dust, bacteria and more from entering your home. Most air filters are fiberglass or paper with a cardboard frame. There are usually at least 1 or 2 in your home, most likely in your hallway or bedroom.

Air filters come in multiple shapes and sizes for different house needs and have a MERV (minimum efficiency reporting value). The MERV is the size and type of contaminants that the filter can protect against.

How long do Air Filters Last?

It’s hard to know how long an air filter will last unless you also know how the conditions of your home affect the lifespan. Use these parameters to determine how long your air filters will last:

Amount of Usage

You will likely not use your air conditioning in the winter or your furnace in the summer. Therefore, you will not be using their air filters. If the climate around your house is mild, then you may only need 1 or 2 air filters to last the whole season.

If you live in an extreme climate or prefer to leave the fan running for longer periods, you will need to replace your air filters every three weeks to maintain the highest HVAC efficiency.

House Size

In the age of van-lifestyles and mini-houses, the appliances can be smaller. If the appliance’s space is smaller, it will require less energy to keep the space cool. However, a smaller filter will also need to be changed more often. 

Take note of the ratio between the size of your unit and the size of your home to decide if you should wait longer periods to change your filter.

Air Quality

The climate of the area around your home also affects the lifespan of an air filter. If the air around contains more contaminates or dust due to construction, you will need to keep the filters changed more often. Pets also affect the air quality. We will discuss that below.

How do I Know I Need to Replace my Airfilter?

Anytime you turn on the fan for warm air or cold, the air will pass through the air filter. That’s why you must change your air filters frequently. If you don’t change your filters, they will no longer filter the air correctly, allowing dust and bacteria to clog the HVAC system. Here are the symptoms of a clogged air filter:

  • The HVAC system is damaged or malfunctioning.
  • There is a lack of airflow or drafts.
  • The air is dusty, or you have often been sneezing.
  • Cause contaminates to build up in your ductwork.
  • Electric bill payments have recently increased.
  • The air filter itself is too dirty to see through.

Check for these symptoms once a month to properly care for your HVAC system and save the most money on electric bills.

How Often Should I Change My Air Filter?

The answer is less simple than you think. The recommendation to change air filters varies. Here are conditions that may affect the lifespan of an airfilter:

Household Size

Larger houses will require a bigger unit and filter. However, if the air filter is a good ratio to the size of the house, you may not need to change it more often.

Model of Air Filter

The most common model of the air filter is an inexpensive fiberglass filter. If you have this type of filter, we recommend that you change it every 30 days.

For 1″–3″ air filters, you should replace them every 1–2 months. This recommendation is the general rule for furnace and AC filters. Pleated filters are more expensive and can last up to 6 months. Add or take away time if the air filter is larger or smaller than usual and if you have any of the below qualities.

Air Quality

If anyone in the household has allergies or asthma, you may want to consider investing in higher-quality air filters or changing them often. It’s just as important to monitor the air quality inside as outside. The air that enters our homes can be filled with many pollutants and can sometimes be even dirtier than the outdoor air. 

If anyone in the home suffers from allergies, consider replacing the air filter every six weeks.

Number of Pets

As the season’s change, your dog or cat can shed more fur. If you have a pet, change your air filter every six weeks. If you have multiple pets or pets and allergies, change the air filter every 2-4 weeks.

Find Reliable HVAC Maintenence in Alexandria, VA

After going through this list, you should have a clear idea of how air filters can make a difference in your HVAC system’s maintenance. Cardinal recommends calling in an expert routinely to inspect and make sure your HVAC system is in tip-top shape. With our team of highly skilled and knowledgeable technicians, we can help you with any of your HVAC needs including air filter replacement. 

Contact Cardinal Plumbing and Air Conditioning today.


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