Two Inch Air Filters

A 2 inch air filter is a pleated filter with about twice the depth of a standard 1 inch filter, made for furnaces and air handlers with a 2 inch slot. That extra depth holds more dust, pollen and pet dander before it fills up, so you'll usually get about 90 days out of one instead of 30.

You'll see the same product called a two inch air filter, a 2" filter, or a 2in filter. They all mean two inches of nominal depth, which is the size you order by.

TL;DR

A 2 inch filter lasts about three times as long as a 1 inch, so you'll buy four a year instead of twelve. It only fits a rack built for 2 inch, so check the last number on your current filter before you order. Filterbuy cuts, pleats and frames them to order in our own US plants, in more than 170 sizes across MERV 8, 11 and 13.

Key Takeaways

• The last number printed on your filter is its depth. If it reads 1, a 2 inch filter won't fit that rack.

• One 2 inch filter covers roughly 90 days, so you'll buy four a year instead of twelve.

• Don't stack two filters in one slot. The second one only sees air the first already cleaned.

• Order by the size printed on the frame. The actual cut is slightly smaller, and that clearance is what lets it slide in.

• Check your HVAC manual for filter compatibility before you pick a MERV tier, the same way you'd check the size.

Will A 2 Inch Filter Fit My Furnace Or AC?

A 2 inch air filter fits if your filter rack or return grille has a 2 inch slot. Pull out the filter you have now and read the frame, where the last of the three numbers is the depth. If it says 1, your system takes 1 inch filters, and a deeper one won't seat properly in that slot.

You'll usually find 2 inch slots in furnaces and air handlers that have their own filter cabinet, and they turn up in older systems and apartment buildings too. If your rack is 1 inch, there's a section further down on what to do about it.

If there's no old filter to read, measure the slot instead. Most people find their size in a minute, and if yours isn't on the list, our custom air filters are cut to the eighth of an inch. Either way, the EPA suggests checking that the filter fits snugly so air doesn't leak around it.

When you put the new one in, check the arrow on the frame. It shows which way the air moves, toward the equipment, and a deeper filter is easy to seat backwards.

1 Inch Vs 2 Inch Vs 4 Inch: What Depth Changes

Depth changes how long a filter lasts, not what it captures. That's what the MERV tier does. At the same MERV, a 2 inch filter packs more pleated material into the same frame, so it holds more dust before it's full and you change it less often through the year.

"People will spend twenty minutes comparing MERV ratings and then order the wrong depth. I have pulled 1 inch filters out of racks built for 2 inch, sitting crooked with a gap around the edge, and at that point the number on the label stopped mattering."

— David Clark, Licensed HVAC Technician, technical reviewer for Filterbuy

Price it by the year rather than by the filter. Multiply by four for a 2 inch and by twelve for a 1 inch, and the gap between them usually closes.

Choosing MERV 8, MERV 11, or MERV 13

MERV is the industry scale for how much a filter captures, and Filterbuy builds 2 inch filters in three tiers. MERV 8 is the standard choice for most homes, MERV 11 is our superior tier for allergy sufferers, and MERV 13 is our optimal, hospital grade tier. Check your HVAC manual for filter compatibility before you choose.

MERV 8 is the standard choice for most homes. MERV 11 is for allergies and asthma, and it's also the one people pick for pets and pollen. MERV 13 is for smoke. If odors are what you're dealing with, our Odor Eliminator filters use activated carbon instead. Whichever tier you land on, check the HVAC manual first, the same way you'd check the size.

Can You Put Two Air Filters Together?

No. Two filters in one slot won't filter better than one, because the second filter only ever sees air the first one already cleaned. If you want more out of your filter, move up a MERV tier instead, and check your HVAC manual for compatibility before you do.

The same goes for stacking two 1 inch filters to fill a 2 inch slot. Order the depth the rack was built for.

Do 2 Inch Air Filters Restrict Airflow?

A 2 inch filter is built for a 2 inch slot, so the thing to check is fit rather than depth. Your HVAC manual lists the filter compatibility for your system, including the depth and the MERV tier it's set up for. Match those, change the filter on schedule, and your system has what it needs.

The same check applies to every tier and every depth we sell. It's a normal part of choosing a filter, no different from confirming the size.

What If My System Only Takes 1 Inch Filters?

Run 1 inch and change it every 30 days. That's the honest answer for most homes. A 2 inch filter won't fit a 1 inch rack, and forcing one in doesn't work. If you want a deeper filter, an HVAC contractor can tell you whether your return can be modified to take one.

That's contractor work, not a weekend project, and it's worth a conversation with someone who can look at your system. Otherwise a 1 inch filter changed every 30 days does the job, and we'd rather tell you that than sell you a filter that doesn't fit.

What The Research Says About Changing Your Filter

Two U.S. government sources make the same point about filter maintenance: the schedule matters more than most people expect. Both are worth a look if you want the detail behind the 90 day guidance on this page, and both are free to read.

• Replacing a clogged filter can lower air conditioner energy use by 5% to 15%. The U.S. Department of Energy also warns that dirty filters can allow air to bypass the filter and deposit dirt on cooling coils, reducing system efficiency. Sources: U.S. Department of Energy, Energy Saver 101: Home Cooling and DOE, Operations & Maintenance Best Practices Guide.

• Manufacturers typically recommend replacement every 60 to 90 days. The EPA also suggests changing sooner if the filter looks heavily soiled when you pull it. Source: EPA, Guide to Air Cleaners in the Home.

Why Your 2 Inch Filter Measures 1.75 Inches

The size printed on an air filter is its nominal size, which is the name you order by. The actual cut is slightly smaller on purpose, and that clearance is what lets the filter slide into the rack instead of jamming. A 2 inch filter measures about 1.75 inches deep. Every manufacturer labels filters this way.

We cut, pleat and frame our own filters, so these figures come off our production floor. A Filterbuy 2 inch filter leaves the line at 1.75 inches deep, and depth is the dimension our team sees ordered wrong most often, which is why we keep telling people to read all three numbers.

So order by the nominal size printed on the filter you're replacing rather than measuring it yourself. Our guide to measuring your air filter size covers what to do when there's no old filter to read.

Where To Buy 2 Inch Air Filters Near You

Searching for two inch air filters nearby usually means a store has already turned out not to carry your size. Big-box shelves hold a handful of common 2 inch sizes and rarely the unusual ones, while Filterbuy makes them in more than 170 standard sizes plus any custom dimension.

Fast and free 2-day delivery is available to most US states, and we're the manufacturer rather than a reseller, so an unusual size isn't a special order on our end.

Frequently Asked Questions

How often should I change a 2 inch air filter?

About every 90 days in a typical home, which sits inside the 60 to 90 day range the EPA cites. Make it 60 days with pets, and 45 during heavy pollen or wildfire smoke. The check needs no calendar: hold the filter up to a light, and if the light doesn't come through the pleats, replace it.

Can I use a 2 inch filter in a 4 inch slot?

No. A 2 inch filter leaves two inches of empty space in a 4 inch rack, so it can shift out of position and let air slide past the edges instead of going through the pleats. Order the depth the rack was built for, or move up to 4 inch air filters.

Can I cut a larger filter down to fit?

No. The frame is what holds the pleats square and seals the filter against the rack, so once you cut it the edges won't sit flush. If your size isn't on the list, our custom air filters are cut to the eighth of an inch, which beats a utility knife.

Are 2 inch air filters washable?

No, ours are made to be replaced rather than washed. Rinsing pleated media soaks the frame and distorts the pleats, so the filter won't seat the same way afterwards. Pull the old one, drop the new one in, and set a reminder for 90 days out.

Find Your 2 Inch Size And Breathe Easy

Read the nominal size off your current filter, pick your MERV tier, and order. If your size isn't on the list, build it with our custom air filters tool. Fast and free 2-day delivery to most US states, and Auto Delivery sends the next one on your schedule.

Glossary

• 2 inch air filter: A pleated filter with a nominal depth of two inches, for racks with a 2 inch slot. Also written two inch air filter, 2" filter, or 2in filter.

• MERV: Minimum Efficiency Reporting Value, the industry scale for how much of the airborne particle load a filter captures. Filterbuy builds MERV 8, 11 and 13.

• Nominal versus actual size: Nominal is the name you order by. Actual is what the filter measures, and it's smaller by design so the filter fits the rack. A Filterbuy 2 inch filter is cut to 1.75 inches deep.

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