AIR & FURNACE FILTER SIZES

We have the largest collection of furnace / air filters on the planet - browse by size!

Simply pick your filter size from one of the drop down menus below...

Shop by whole house filter brand

Need to replace a branded whole house filter? We've got replacements for over 40 brands (and counting). The most common brands are listed below but if you don't see your brand listed go to our whole house replacement page and find your brand.

We also carry replacement filters for every major brand

Custom filter sizes

Don't see your size? Create one yourself using our custom filter tool!

Choosing the best filter for your home or business.

Proper maintenance of your home’s heating and cooling system requires periodic filter changes. Just as you ought to change your engine oil and oil filter every few thousand miles in your vehicle, you must also replace what is considered to be a key component of your HVAC system – the filters. You’ve probably heard a technician refer to furnace filters and air filters, right? If so, keep in mind that that a furnace filter and an air filter are the exact same thing!  You will commonly find technicians referring to your filter as a ‘furnace filter’ in the winter and an ‘air filter’ in the summer. The reality is that both are made out of the exact same material and are completely interchangeable. In fact, in most residential homes both functions are performed by the same HVAC unit.

The most important thing to remember when choosing your HVAC filter is to secure the exact air or furnace filter size by selecting the correct length x width x depth. If you can’t find the size written on the side of your filter, simply measure your filter with a tape measure. It is important to use only the correct size when replacing your filters, as a filter that is too small can allow damaging particulates to enter the air stream, while those that are too big may not fit the filter housing and can lead to airflow issues. Beyond the length and width of each filter, ensure that the depth measurement is appropriate to keep the HVAC system running properly. Variations in filter thickness can affect airflow to the home or building, and some systems will suffer from reduced airflow when non-stock filter sizes are used.

Browse our incredible selection of air filters today and find the exact replacement item to keep your indoor air clean and healthy. You can order by size on this page, making the process of finding top-quality replacement filters for your HVAC system a no-stress affair. Once you have determined the right size for your application, simply write the dimensions on the inside of the filter housing using a permanent marker. This will eliminate having to remember the size during your next order. Better yet, set up a recurring order plan that automatically sends new filters directly to your front door – without any hassles, guaranteeing that you’ll always have clean air in your building or residence.

*Note. All filters are listed by nominal size unless specified otherwise by the inclusion of (Actual) at the end. You can read more about nominal vs. actual air filter size by clicking here.