Depending on whether you live in an apartment or house, your HVAC system is likely in a closet or basement. You'll find your air filters in blower compartment in front of the air handler.

Colorfil filters are meant for HVAC systems, furnaces, and central air returns, and if the sizing is compatible they can work with air purifiers.

Here are three common types of systems:

Vertical Up-Flow System
These systems are common in North American homes. They are installed upright and circulate air through the side or bottom, pushing it through the top. The location of your air filter in these systems can be found at the bottom of the unit.

Vertical Down-Flow System
Airflow in a down-flow system comes in at the top and flows out at the bottom. These systems are usually installed in closets, and your filter will probably be at the top of the unit.

Horizontal System
Horizontal units are usually located in attics and crawl spaces and appear lying on their sides. Air flows in from one side of the system through the filter and out the other. Your filter will likely be installed vertically on the side of your return duct for these units. If you still need help finding your filter, we suggest contacting a qualified technician for your next tune-up.

After you find your HVAC system and your air filter, check to see if your current filters say the size on them. If not, you'll have to measure the exact length, width and depth of the filter you have. Then, check out our size guide to find the one that's right for you.

The first step is ensuring you have the correct size filter for your unit. The size of your filter will be found on the frame, whether it's a disposable or a reusable, washable filter. For filters that don't indicate size, use a measuring tape to measure the filter's length, width, and thickness. Use these numbers to select and purchase your new replacement filter.

The second step to replacing your air filter is to turn off your air conditioner or heater via your thermostat. Turning your unit off will help protect your HVAC system from loose dust and dirt from the old filter that could get sucked into your system. Also, it will be easier to replace the old filter without the air pressure of the furnace blower.

The next step is to remove the old filter. As you do so, please take note of the direction of the arrows on the frame's edge. Insert the new filter with the arrows facing the same direction as those on your old filter.

The arrows should point in the direction in which air is flowing. If you have a ceiling-mounted filter, it should face up. If you are installing a filter next to your unit's blower, it will typically point toward that blower.

The proper placement is essential to getting the maximum benefit from your heating and cooling system. When replaced incorrectly, it can cause your system to work harder than it should, resulting in higher energy costs. If you follow these steps, you'll be good to go.

If you have questions regarding your purchase, subscription or want to discuss a return, please fill out this form and someone from Colorfil will contact you with next steps.

Add your filter to cart, and your free second filter will be applied automatically at checkout. No code needed. Both filters ship together, so you'll have a backup ready the moment your first one turns yellow.