The timely replacement of your furnace filter is a lot easier when you know what air filter size you need. AC filters are available in many different sizes, so it can be overwhelming if you’re not sure what size filter you need.
We don’t recommend relying on what you think is the right size and we don’t want you to feel uncertain when it comes to ordering your HVAC filter. At FiltersFast.com, our goal is to equip you with the knowledge you need to make the right decisions.
Why do you need the right size air filter?
If an air filter is too big, you will have to return it. DO NOT cut it to fit. Cutting a filter to fit can create air gaps and contaminants can pass through into your air.
The longer you wait to change your old, clogged filter, the more restricted airflow can become. When airflow is restricted two things can happen:
- Your energy bill will start increasing because hot or cold air can become trapped behind a wall of particles.
- Your HVAC system will have to run for longer because hot and cold air is not circulating properly.
- Your indoor air quality will become poor because fresh, clean air is unable to flow into your home.
If an air filter is too small, this will create air gaps and contaminants will bypass the filter material.
How do you figure out the right air filter dimensions you need?
Here are three easy ways to determine the right size air filter you need:
Check your current air filter!
In most cases, the air filter dimensions will be printed on the side of the filter.
Air filter dimensions are written as length, width, and depth (for example: 18x20x1). You can use a tape measure to get the size of your existing filter You should have three numbers written in inches. This is what is called “actual dimensions”.
If you measure your filter, you may find that these measurements are not round numbers.
When shopping for air filters, you will see the words “nominal size” and “actual size” together. The reason for this is that many air filters are not cut to an exact size. Normally, we see air filters being around 1/8″ to 1/4″ smaller than advertised. This guarantees that if your air conditioning system is designed for 18x20x1 if that number is off by even a little bit the filter will still fit.
Air filters come in tons of standard sizes, but if you are having trouble finding the size that you need, FiltersFast.com can make custom furnace filters for you!
Check your HVAC owners manual!
If all else fails, refer to your air conditioning system product manual or contact the manufacturer directly with your system model number. They can help you figure out the exact filter specification for your unit.
If you buy your air filters from FiltersFast.com, your filter information is stored in your customer profile, so all you have to do is reorder!
Wish there was an easier way to remember what size air filter you need and when to change it? Sign up for our air filter subscription service! Our FiltersFast.com Home Filter Club allows you to find the filters you need, select how often you’d like to have them delivered and you’re done!