You can find air filters online and at your local hardware shop. For optimal performance, purchase replacement air filters from a reputable manufacturer. You can see prices for various high-quality air filters online. A simple way to choose a replacement filter is to just purchase the identical filter that is currently installed in your system.

But if that is unavailable, or if you want something less expensive or that performs better, here is how to proceed. Air filters typically come in various conventional sizes, while a select few can be adapted to fit a variety of filter-box or return-air opening sizes.

Find Out Which Air Filter Size You Need

Typically, this entails locating your existing filter first. HVAC filters are usually installed in a slot adjacent to the furnace or air handler. However, some HVAC systems contain filters within the return air ducts that are dispersed throughout the rooms in your home. These grates draw air in instead of expelling it.

After locating each filter, verify that it is the correct size, as measured in inches of height, width, and depth — or thickness. If there are gaps around the sides or if it does not align with any gaskets, it may be the incorrect size.

If your existing filters fit perfectly, record the size printed on the filter frame. Check the owner’s manual for your equipment, or contact the manufacturer if you are unsure of the correct filter dimensions. Typically, a hardware store will have the necessary filter size in stock, but sometimes you will need to order it online.

Big Box Retailers

You can go into a popular big box store like Home Depot or Lowes and find air filters in the heating, ventilating, and cooling departments. The advantage of going in person is that you can feel and see the air filters for yourself before making a purchase. In addition, you can ask staff to help you when deciding between filters.

Online Vendors

There are many brands online that sell air filters that are just as good as the ones in the big box stores, if not better. Sometimes, these online vendors have special deals or discounts as part of their ongoing sales promotions.

Plus, the added benefit is that you can shop from the comfort of your own home and receive prompt delivery within the week or the next couple of days, depending on the shipping option you choose.

Choosing Your Filtration Level

Any pleated HVAC filter can improve the air quality of a home by capturing dust, pollen, and other particles, similar to a quieter, less active vacuum. However, a filter that is too dense for your system can make it difficult to heat and cool your home properly and efficiently. It may also damage your furnace, air conditioner, or heat pump as components overheat or freeze.

An unnecessarily loose filter is also undesirable. It’s a missed opportunity to breathe better air, and the accumulation of grime on the blower and coils could damage your HVAC system over time. Finding the optimal level of filtration is locating the “sweet spot” — a filter that permits sufficient airflow through your ducts while capturing as much dirt as possible.

To determine with certainty how much airflow your HVAC system needs to perform effectively, you must measure the static pressure. Essentially, this is the resistance to airflow through your ducts.

Experts occasionally advocate using a MERV 8 pleated filter as a safe alternative if you do not know what your system usually takes. These filters permit ample airflow. Therefore, they are suitable for most systems. Additionally, they are inexpensive and capture significantly more particles than standard fiberglass filters.

Installing Your New Air Filter

You may need a screwdriver or pliers to open a hatch or cover to access the filter. Typically, the installation consists of sliding or popping out the old, soiled filter, then sliding the new, clean filter into the slot. Ensure that the new filter is installed correctly; look for arrows on the filter frame that indicate airflow direction.

Buy in Bulk or Arrange Recurring Shipments

Once you have learned how to replace your furnace filter, you should make it a habit. It is all too easy to forget to replace air filters, so it is advisable to create a reminder in your calendar or set an alarm on your phone to check the filter’s condition.

Purchasing replacements in bulk or setting up a recurrent shipment can also help you maintain consistency and limit the likelihood of procrastinating with replacements.

Maintaining a clean air filter in your HVAC system can cut your electricity bill by up to 15%. A blocked air filter can significantly increase an electric bill during periods of excessive usage, especially in the winter, yet a replacement filter costs only a few dollars. Consequently, it is highly advantageous to keep up with furnace filter replacements.