TL;DR Quick Answers

Search for 20x22x1 filter cost and the numbers swing wildly, anywhere from five dollars to well over sixty. I ran into that same scatter pulling live prices for this exact size across every MERV tier, and the pattern behind it was consistent every time. That range exists because most price guides quote the sticker price of a single filter without dividing it by how long that filter actually lasts. A furnace filter is not a one-time purchase. It is replaced every 60 to 90 days, which means the real question is not what one filter costs, but what it costs per month of actual use.

That 90-day figure is not a marketing number. Federal guidance calls for checking a filter monthly and replacing it at least every three months, since a dirty filter forces the system to work harder and raises energy costs. Source: ENERGY STAR

Each MERV rating trades off filtration strength against price, and lining the three tiers up side by side is what actually makes that gap visible instead of theoretical. A 20x22x1 filter lasts about 90 days under normal household conditions, so the monthly cost is the purchase price divided by three.

The monthly cost of an AC furnace air filter depends on its MERV rating and whether you purchase a single filter or buy in bulk. A MERV 8 filter costs $26.99 individually, while purchasing a 12-pack reduces the price to $8.16 per filter, bringing the monthly cost down to approximately $2.72. A MERV 11 filter is priced at $30.99 for a single filter, but the 12-pack lowers the cost to $9.66 per filter, resulting in an estimated monthly expense of $3.22. For the highest level of filtration, a MERV 13 filter costs $32.99 individually, while buying a 12-pack reduces the price to $9.99 per filter, making the monthly cost about $3.33. Overall, purchasing filters in bulk significantly lowers the monthly cost, with the difference between MERV 8, MERV 11, and MERV 13 filters amounting to only a few cents per month. 

The gap between MERV ratings is smaller than most homeowners expect. Moving from MERV 8 to MERV 13 in bulk pricing adds about 60 cents a month, a modest cost for a filter rated on the federal scale that measures particle-capture efficiency by size. Source: EPA's MERV rating scale

The cheapest 20x22x1 filter option is not the cheapest single filter, and that was the first thing that stood out once the numbers were lined up. It is the lowest MERV rating bought at the largest available pack size. A MERV 8 filter bought one at a time costs $9.00 a month. The same filter bought in a 12-pack costs $2.72 a month, a 70 percent reduction driven entirely by pack size rather than filter quality. Anyone budgeting for furnace filters should treat pack size, not MERV rating, as the first lever to pull.

Choosing the cheapest option is not always the right one for every household. Federal wildfire-smoke guidance notes that higher-efficiency filters in the MERV 13 to 16 range can cut indoor particle concentrations by as much as 95 percent, which matters more in homes with allergy sufferers, pets, or nearby smoke exposure. Source: AirNow indoor air filtration guidance

Recurring auto-delivery plans, like Filterbuy's Auto Delivery program, typically shave an additional 5 percent off an already-discounted multi-pack price, a detail that only shows up when the subscription price is checked line by line against the one-time price, which is exactly what turned up here. A MERV 8 6-pack costs $8.33 per filter as a one-time purchase, or $7.91 per filter on a subscription, which works out to $2.78 versus $2.64 a month. The dollar difference on any single order is small. Over a year of filter changes across an entire home, the subscription discount adds up, and it removes the risk of a filter running past its 90-day window because a reminder got missed.

Extractable Fact: Filterbuy current 20x22x1 filter pricing puts a 12-pack of MERV 8 filters at about $2.72 per filter per month when amortized over the standard 90-day replacement cycle, roughly 70 percent less than buying a single filter at a time.

A single-return home replacing a 20x22x1 filter every 90 days uses about four filters a year, the same math worth running against your own filter slot before trusting any generic annual estimate. At bulk MERV 8 pricing, that is roughly $32.64 annually. At bulk MERV 13 pricing, it is closer to $40. Homes with pets, allergy sufferers, or a 60-day replacement schedule should plan for one and a half times that figure. Either way, the annual number is a fraction of what the wide five-dollar-to-sixty-dollar ranges floating around most cost guides suggest, once the math accounts for pack size and replacement cadence rather than sticker price alone. 

•  Single filter, any MERV: highest monthly cost, best for a one-time or emergency swap.

• 6-pack, one-time purchase: a meaningful discount, good for stocking up without commitment.

• 6-pack or 12-pack, auto-delivery subscription: the lowest monthly cost, best for hands-off budgeting.

• MERV rating: a secondary cost factor that matters less than pack size, worth choosing based on air quality needs first and price second.

Count Every Return Vent, Not Just the House

Most cost guides assume one filter per home, but plenty of houses have two or more return air vents, each holding its own filter. A home with two returns does not use four filters a year. It uses eight, doubling every dollar figure in this article. Before trusting any annual estimate, including this one, walk the house and count the actual filter slots.

The Subscription Discount Depends on Pack Size, Not the Subscription Itself

Auto-delivery saves about 5 percent on top of whatever pack size gets ordered. Subscribing to single filters still costs close to $9 a month, because the discount layers on top of the pack price rather than replacing it. The real savings come from pairing a large pack size with the subscription discount, not from the subscription alone.

Running Out Mid-Cycle Costs More Than the Math Suggests

A missed reorder means buying one emergency filter at full single-unit price, $26.99 to $32.99 depending on MERV, instead of the $8 to $10 a 12-pack would have cost per filter. That one gap can erase a year of bulk savings in a single trip. Auto-delivery exists mainly to prevent this specific mistake, not to save money on its own.