Is MERV 13 Too Restrictive?

• The extra resistance is small, and it depends on the brand. At the same test airflow, a new MERV 13 resists from no more to 0.10 inches of water more than the same maker's MERV 8. Filtrete 1900 (MERV 13) and Filtrete 700 (MERV 8) both filed 0.18. Aerostar and Amazon Basics go from 0.18 to 0.28. Honeywell's MERV 13 filed 0.35, the most of any here.^[1]
• The filter size and your airflow matter more than the MERV. A furnace is usually rated to push against about 0.5 inches in total, for the filter, coil and every duct. Design rules leave 0.10 of that for the filter. At the top state test speed (about 1,000 cfm through a 16x25x1), even a new MERV 8 filed 0.24 to 0.26: about half the whole budget, before any MERV 13.^[4]
• Most homes already run above the rating. The National Comfort Institute found the average system it tested running at 0.82 inches, above the 0.5 most blowers are rated for. A study of 34 California homes measured 0.28 inches across the filter alone. If your system is one of these, every bit of extra filter resistance costs airflow.^[4]

Resistance of a new 1-inch filter at the middle test speed makers use for the state list (about 295 feet per minute through the filter), in inches of water. These are the numbers each maker filed with the California Energy Commission, which keeps the state's list of certified air filters.^[1]

Nordic Pure is not on the state list, so its row is its own guide and is shown for reference. Filtrete files its MPR lines: 700 is MERV 8, 1000 is MERV 11, 1900 is MERV 13. Numbers are for a clean filter; they rise as it loads.

The state test runs each filter at several airflows. Here are the three that cover most homes, in cubic feet per minute (cfm), with the cooling size that airflow fits at 400 cfm per ton. Resistance is in inches of water. Find your size and the airflow nearest your system.^[5]

Each size lists only the filters a maker filed in that exact size. Filtrete filed one size per line (20x25x1); Honeywell filed 20x20x1. A row naming two brands means the same maker filed the same numbers for both.

Every filter slows the air a little. The push your blower needs to get air through the filter, the coil and the ducts is called static pressure. It is measured in inches of water. Lower is easier on the blower.

A typical furnace or air handler is rated for about 0.5 inches in total. Energy Vanguard, a building-science firm, puts it this way: if the filter alone uses half of that, the system will not move the air it was built to move. Then the AC coil can ice up, and a furnace's heat exchanger runs hotter.^[3]

Goodman's spec sheet shows what that costs. Its 60,000 BTU furnace (model GR9S800603A), sized for a 3-ton air conditioner, moves 1,224 cfm on cooling speed F05 at 0.3 inches and 1,167 cfm at 0.5. Each extra 0.1 inch costs about 28 cfm, roughly 2% of the air.^[2]

That same furnace calls for one 16x25 filter. At 1,167 cfm, air moves through a 16x25 at about 420 feet per minute, faster than the fastest speed makers test for the state list (about 369). At that top test speed, about 1,000 cfm, a new 1-inch MERV 13 resists 0.26 (Filtrete 1900) to 0.48 (Honeywell), or 52% to 96% of a 0.5-inch rating.^[1]

• Your air is already weak. If rooms are slow to cool or the air at the vents feels weak with your current filter, a denser filter will make it worse.
• Your blower is an older single-speed type. Researchers found a clear trend toward lower airflow with higher-MERV filters in systems with single-speed (PSC) blowers. One study measured 7% and 11% less air in two systems after a switch to MERV 11. Newer variable-speed blowers hold airflow, but use more power to do it.^[4]
• One 1-inch filter serves a big system. A rule from Energy Vanguard: at least 2 square feet of filter for each 400 cfm, which is about one ton of cooling. One 16x25 is 2.8 square feet, enough for about 556 cfm at the 200 feet per minute experts aim for. Goodman itself calls for two 16x25 filters on its furnaces paired with an air conditioner over 4 tons.^[5][2]
• You forget to change it. Every number on this page is for a clean filter. Resistance climbs as a filter fills with dust, so change a 1-inch filter every 60 to 90 days, the EPA says.^[6]

• Pick the MERV 13 that resists least. Brands differ more than MERV numbers. On the state filings, Filtrete 1900 resists 0.18 inches at the middle test speed; Aerostar's MERV 13 0.28 and Honeywell's 0.35.^[1]
• Step down to MERV 11. It still catches fine dust, mold spores and pet dander, and it is the right filter for most homes. Use it if the signs above fit your system.
• Get more filter area. A 4-inch filter cabinet gives the air far more filter to pass through, so a MERV 13 there resists less, and makers say it lasts 6 to 12 months. Many furnaces can also take a second return or a bigger filter grille; an HVAC tech can tell you. See which 4-inch filter fits your cabinet.

Is MERV 13 too high for a home?

Usually not. The EPA says most furnaces and HVAC systems can take a MERV 13 filter without problems. On the state filings, a new 1-inch MERV 13 resists at most 0.10 inches of water more than the same maker's MERV 8.

Can my furnace handle a MERV 13 filter?

Most can. Be careful if airflow is already weak, the blower is an older single-speed type, or one 1-inch filter serves a system of 3 tons or more. In those cases use MERV 11, or a 4-inch filter cabinet.

Does a MERV 13 filter restrict airflow?

A little more than a MERV 8, and how much depends on the brand. Filtrete's MERV 13 filed the same resistance as its MERV 8 (0.18 inches). Aerostar's filed 0.28 vs 0.18.

Is a MERV 11 filter too restrictive?

Rarely. MERV 11 sits between MERV 8 and 13 on most filings (Aerostar: 0.24 inches). Filtrete 1000 (MERV 11) actually filed more resistance (0.22) than Filtrete 1900 (MERV 13).

Is MERV 13 OK with a heat pump?

Usually, with the same cautions. If your heat pump has a variable-speed blower, it keeps airflow up against a denser filter but uses more power to do it, Energy Vanguard notes. A low-resistance MERV 13 or a 4-inch filter keeps that cost down.

Is a 4-inch MERV 13 better than a 1-inch?

For airflow, yes. A 4-inch filter has far more filter material, so air passes through it more easily. Makers say it lasts 6 to 12 months, against 60 to 90 days for a 1-inch.

How do I know if my filter is too restrictive?

Weak air at the vents, rooms that won't cool on hot days, a system that runs much longer, or ice on the indoor coil or refrigerant line. An HVAC tech can measure static pressure in a few minutes.

• What MERV rating do I need?
• Best furnace filters: pick MERV 8, 11 or 13 in your size
• Filtrete vs Nordic Pure vs Aerostar
• 4-inch filters for Aprilaire, Honeywell and Lennox cabinets
• Best air purifiers

Resistance numbers are the California Energy Commission's Title 20 air-filter records, read from the state database between October 22 and November 11, 2026. Makers run the standard lab test (ASHRAE 52.2) and file the results. We did not test filters ourselves. Numbers are for a new, clean filter.

Static pressure figures come from the sources named: Goodman's furnace spec sheet, and Energy Vanguard's summaries of ACCA design rules, National Comfort Institute field tests and published filter studies. Cooling size uses 400 cfm per ton.

Picks and prices come from our Filtrete vs Nordic Pure comparison and our furnace filter page, so every page names the same filter at the same price. We do not give star ratings.

More on how we work: our methodology.

1. 1

   California Energy Commission, Modernized Appliance Efficiency Database: Air Filters (Title 20)

   26 records read October 22 to November 11, 2026: Filtrete 700, 1000, 1900 (3M Company); Aerostar P80S, P15S, P25S and Amazon Basics BP80S, BP15S, BP25S (Con-Air Industries); Honeywell P11-14-1-2020A, T13-18-1-2020A (PPA Industries); Filter King FK20X20X1-M13 (Filter King LLC). ASHRAE 52.2 test; initial resistance at each test airflow.

2. 2

   Goodman GR9S80 / GD9S80 gas furnace specification sheet (SS-GR9S80_GD9S80-R32, 07/25)

   GR9S800603A fan table, speed F05: 1,308 cfm at 0.1, 1,262 cfm at 0.2, 1,224 cfm at 0.3, 1,197 cfm at 0.4, 1,167 cfm at 0.5, 1,141 cfm at 0.6, 1,117 cfm at 0.7, 1,089 cfm at 0.8 in.; "Available AC @ 0.5” ESP" 3 tons; minimum filter (1) 16 x 25; "Use 2 - 16 x 25 filters on side returns or 20 x 25 filter on bottom return if furnace is connected to a cooling unit over 4 tons nominal capacity."

3. 3

   Energy Vanguard (Allison Bailes), The Unintended Consequences of High-MERV Filters (2018)

   "If your system is rated for a total pressure drop of 0.5 inches of water column (i.w.c.) and you use up half of it just at the filter, you’re not likely to get the amount of air flow the system was designed to deliver."

4. 4

   Energy Vanguard (Allison Bailes), Do High-MERV Filters Always Reduce Air Flow? (2019)

   "The Air Conditioning Contractors of America (ACCA) protocols for HVAC design assume a pressure drop of 0.10 inches of water column (i.w.c.) across the filter." "The typical furnace or air handler is rated for 0.5 i.w.c. but many run much higher pressure." National Comfort Institute average 0.82 i.w.c.; Proctor: 0.28 i.w.c. across the filter in 34 systems; Stephens et al.: airflow 7% and 11% lower with high-MERV filters.

5. 5

   Energy Vanguard (Allison Bailes), The Path to Low Pressure Drop Across a High-MERV Filter (2019)

   "Filter Area = 2.0 square feet (or more) for each 400 cfm of air flow." Target face velocity 200 fpm or lower.

6. 6

   EPA, Guide to Air Cleaners in the Home

   "Most furnaces and HVAC systems can accommodate a MERV 13 filter without creating equipment problems"; "replacement every 60 to 90 days"

7. 7

   Nordic Pure, MERV Data Product Guide (PDF)

   1-inch initial resistance at 300 fpm: MERV 8 0.14, MERV 11 0.24, MERV 13 0.26 in. w.g.

8. 8

   Amazon listings checked in stock

   Buy boxes read November 11, 2026; prices change often