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Changing the air filter on your HVAC system is one of those home maintenance tasks, like winterizing your garage, cleaning your gutters, or prepping your yard for colder weather, that's annoying but necessary. In fact, changing your air filter is crucial for keeping pollen, dust, pet dander, and even viruses from circulating through your home. Fail to change your air filter in a timely manner and you end up with a clogged filter, poor air quality in your home and poor HVAC efficiency.
Generally speaking, you should change the filter, or filters, in your HVAC system once about every three months. Just how often you should replace the filter depends on several factors, such as filter type, season, and your family’s sensitivity to allergens. Along with knowing how often to change your HVAC filter, knowing the type and efficiency level that’s right for your home is also crucial. Here's everything you need to know to properly change your HVAC filter.
What Is an Air Filter and How Does It Work?
Air filters are part of your home’s HVAC system and work with air conditioning units, furnaces, and heat pumps. Your home has one or more returns that pull in air from your home into the HVAC system, which then cools or heats it before sending it back into your home. Those return vents have filters that remove dust, pollen, pet dander and other particles in order to improve air quality and to protect your HVAC system from debris that can damage it as it’s cycling air in your home. Air filters come in various sizes and types to suit different size returns.
How Often Should You Change Your HVAC Filter?
Generally, you should change your HVAC filter once every three months. That can vary from home to home, depending on how hard your HVAC system is working to warm or cool the air in your house. You can also tell if your air filter needs to be changed if the air flow from the vents in your home feels weaker, there are unpleasant odors coming from the system or your HVAC system is cycling on more frequently.
Factors To Consider When Choosing an Air Filter
Filter type
There are two types of filters to choose from: pleated and fiberglass. The main difference between the two is cost and efficiency.
- Fiberglass air filters consist of spun glass fibers that trap particles as air passes through. They’re not as effective at trapping smaller particles, such as dust and pollen, as pleated filters and generally need to be changed more often.
- Pleated air filters use an accordion-style surface made from cotton or polyester that captures dust, pollen, and other small particles. They’re far more effective at trapping particles than fiberglass and, while more expensive, last longer.
Home size
The size of your home is significant because it determines how much air your HVAC system must cycle to condition it. A large home that has to cycle more air will wear out an air filter faster than a smaller home. Newer homes also have multiple returns, each of which has its own air filter and hence shares the load of filtering the air in the house.
Air quality
Your home’s air quality also makes a big difference in how often you change an air filter. Homes with high amounts of dust, pets, and even outdoor air quality can impact just how quickly your air filters get dirty.
Allergies
How sensitive your home’s occupants are to dust, pet dander, and other allergy inducing particles also factors into how often you change your air filter. If you have family members who are highly sensitive to allergens, you may need to change your filter every one to two months instead of every three or invest in a higher quality filter (more on that below).
Season
The time of year can also impact how long your air filter lasts. During more temperate months in the fall and spring when your HVAC works less often, you may not need to change your filters as often as in the winter and the summer when your HVAC system works harder to cool or heat your home.
Occupancy
More people create more dust, shed more skin cells and generally produce more airborne particles. Thus, the more people in your home, the quicker your air filters will get dirty and the more often you’ll need to change them.
How To Change Your HVAC Filter
Changing your HVAC filter is one of the easier maintenance jobs in your home. Here’s how:
- Step 1: Turn off your HVAC system at the thermostat.
- Step 2: Locate the return or returns in your house. Your return will be a large metal grate that’s either on the ceiling or wall of your home. If you don’t have any returns, then the filter may be located directly on the HVAC unit’s air handler. The air handler is typically in a utility closet, attic, basement, or crawl space.
- Step 3: Return grates have two clips that hold them closed. Open these clips and remove the cover to the grate. You’ll see the old air filter inside. Note the size and replace it with an air filter that's the same size.
- Step 4: Remove the old air filter and replace it with the new one. Install the new air filter so that the arrow on the side of the filter, which shows the air flow, points into the return. For changing an air filter that’s at the air handler, open the air filter cover, slide out the old filter and slide in the new one, making sure the air flow arrow on the filter points into the air handler.
- Step 5: Close the grate or air filter cover and turn on the HVAC system.
Related: Get Rid of Mineral Deposits on Your Faucets Fast With These Home Cleaning Staples
What Do MERV Ratings Mean for HVAC Filters?
When shopping for replacement air filters, you’ll notice that they come with various MERV ratings. MERV stands for Minimum Efficiency Reporting Value, which is a measurement of the filter’s effectiveness at filtering out particles. MERV ratings range from 1 to 20. The higher the rating, the greater a filter’s ability to trap smaller particles. Filters with higher MERV ratings also cost more. Consider the level of air quality that’s best for your family when determining what level filter to purchase:
MERV 1-4
This is a basic air filter that’s capable of catching larger particles, including dust, dust mites, carpet fibers, and pollen.
MERV 5-8
These filters have the ability to catch finer dust particles including mold spores and pet dander. Invest in these higher-rated filters if occupants in the house have sensitive allergies.
MERV 9-11
Along with dust, pollen, and pet dander, these higher-performing air filters can filter out mold spores and bacteria, making them a good option for households with family members who suffer from mold allergies.
MERV 12-13
These are the highest rating air filters you can find for home HVAC systems. Along with everything that lower level air filters can filter out, MERV 12-13 air filters will also remove viruses, smoke, allergens, odors, and even smog. This high performance filter is a good choice if members of your family deal with respiratory issues, such as asthma.
MERV 16-20
These high-performance filters are designed to offer the filtration needed in hospitals and schools. These types of filters are not suitable for home HVAC systems due to the amount of air resistance they create.
How To Tell if an HVAC Filter Needs Changing?
Not sure if it’s time to change your air filter? Open the return and examine the filter. New air filters are typically white. If the filter looks dirty or black, then it’s clogged with particles and needs to be changed.
What Happens if You Haven’t Changed Your Air Filter in a Year?
If you’re not changing your air filter regularly, then you’ll likely begin to experience poorer air quality in your home and higher utility bills. Clogged air filters not only allow more contaminants to remain in the air in your home but also strain your HVAC system as a clogged filter restricts air flow.
Do New Homes Need More Frequent Air Filter Changes?
New homes do need more frequent air filter changes than existing homes. This is due to the fact that there is more dust in the air from construction and finishing materials. It’s a good idea to change your air filter every one to two months during the first year in a new home.
