Furnace filters, scored

Ranked by composite. We score the true ANSI/ASHRAE 52.2 MERV, not the proprietary MPR (3M) or FPR (Home Depot) scales that obscure it. Annual cost is computed from the per-filter price and the manufacturer's replacement cadence.

Score	Filter	True MERV	Depth	$/yr
6.6	Aprilaire 213 (4-inch media, MERV 13)	MERV 13	4"	$69
6.6	Aprilaire 413 (4-inch media, MERV 13)	MERV 13	4"	$69
6.0	Honeywell FC100A1037 (4-inch media, MERV 11)	MERV 11	4"	$65
5.9	Aerostar MERV 13 (1-inch)	MERV 13	1"	$18
5.4	Lennox Healthy Climate X6673 (5-inch media, MERV 11)	MERV 11	5"	$72
5.2	Nordic Pure MERV 12 (1-inch)	MERV 12	1"	$36
5.2	Amazon Basics MERV 11 (1-inch)	MERV 11	1"	$34
3.7	Flanders EZ-Flow II Fiberglass (throwaway)	MERV 1	1"	$30
3.3	3M Filtrete MPR 1900 (Premium Allergen)	MERV 13 (MPR 1900)	1"	$80
3.3	3M Filtrete MPR 1500 (Allergen)	MERV 12 (MPR 1500)	1"	$72
2.3	Honeywell Home Elite Allergen FPR 10 (1-inch)	MERV 13 (FPR 10)	1"	$108

Why some big-name filters score lower: a brand that hides its true MERV behind a proprietary MPR or FPR number is capped on rating honesty, and a high-MERV filter in a thin 1-inch panel is flagged for airflow restriction. See the methodology.