A 20x25x5 air filter sits in a media cabinet bolted to the return side of the furnace. Moving that cabinet from MERV 8 to MERV 13 costs $10.00 more on a Honeywell 2 Pack and $36.00 more on an Air Bear 2 Pack. Those two numbers are the whole price of the upgrade.
The pleat pack inside a deep media filter runs five inches deep, five times the depth of a one inch panel. That depth is what makes MERV 13 practical here. Five inches of pleat spreads the same grade of media across several times the face area. The blower meets less resistance than a one inch MERV 13 panel puts in front of it.
Poseidon Filters stocks 21 deep media furnace filters. They cover five nominal sizes across three cabinet brands. This guide gives the 20x25x5 prices first, then the full grid for anyone standing at a different cabinet.
Read the Size Off Your Old Filter Before You Order
Deep media filters print their nominal size along one edge of the cardboard frame. Pull the old filter out of the cabinet and read that edge first. The number appears as three figures separated by an x, such as 20x25x5. The first two figures give the face dimensions and the third gives the depth.
Two other places have the number when the old filter has gone missing. The cabinet door usually has a label with the filter size and the cabinet model number. The furnace or air handler manual also lists the filter the cabinet takes.
One caution matters here. Nominal size and a tape measure rarely agree, because manufacturers round the printed number. Ordering against a tape measurement produces the wrong filter more often than the right one. Order against the printed number every time. A filter that misses the cabinet gasket by a quarter inch lets unfiltered air run straight past the media.
The frame has one more mark worth a look. Deep media filters print an airflow arrow along one edge, and that arrow points toward the blower. Set the new filter so the arrow follows the air into the cabinet.
What a MERV 13 Upgrade Costs on a 20x25x5 2 Pack
Every deep media filter on the site ships as a 2 Pack. Every filter below was in stock and every price below was live in the Poseidon catalog on August 23, 2026.
| Cabinet brand | MERV 8 | MERV 11 | MERV 13 |
|---|---|---|---|
| Honeywell 20x25x5 | $79.99 | $79.99 | $89.99 |
| Air Bear 20x25x5 | $59.99 | $84.99 | $95.99 |
Read the two brands separately, because they price differently. A Honeywell owner moving from MERV 8 to MERV 13 pays $10.00 more on the 2 Pack. That is $5.00 per filter change. An Air Bear owner moving the same two grades pays $36.00 more on the 2 Pack, or $18.00 per filter.
The Honeywell cabinet prices MERV 8 and MERV 11 the same, both at $79.99, and asks $10.00 more for MERV 13. A Honeywell owner buying MERV 8 today is already paying MERV 11 money.
The 20x25x5 opening has two MERV 13 products. The Honeywell 20x25x5 Furnace Filter MERV 13 2 Pack is $89.99, and the Air Bear 20x25x5 Furnace Compatible Filter MERV 13 2 Pack is $95.99. The label on the cabinet door decides which one belongs in the cabinet.
Match the Filter to Your Cabinet Brand
Cabinet brand governs the frame build and the way the filter seats against the gasket. Three brands cover the Poseidon deep media range.
| Brand on the cabinet door | Depth | Nominal sizes stocked | Product title on the site |
|---|---|---|---|
| Honeywell | 5 inch | 16x25x5, 20x20x5, 20x25x5 | Furnace Filter |
| Air Bear | 5 inch | 16x25x5, 20x25x5 | Furnace Compatible Filter |
| Space Gard | 6 inch | 16x28x6, 20x25x6 | Furnace Filter |
Every size on that table comes in all three MERV grades as a 2 Pack, so the 21 products fill the grid with no gap. A household running MERV 8 today can step to MERV 13 in the same cabinet and change no hardware. Across all 21 deep media 2 Packs, prices run from $59.99 to $99.99.
Honeywell covers every five inch size in the deep media range. Air Bear cabinets take a filter Poseidon lists as a compatible version, which is why the Air Bear titles read Furnace Compatible Filter. Space Gard cabinets run six inches deep, and a six inch pleat pack will not close into a five inch cabinet.
A 16x25x5 or a 20x25x5 opening appears under both a Honeywell label and an Air Bear label. Those two filters share a nominal size and differ in frame build. The door label settles it.
Choosing a MERV Grade for a 5 Inch Cabinet
MERV stands for Minimum Efficiency Reporting Value. The ASHRAE 52.2 test behind the rating measures what share of each particle size range a filter captures. The fine end of that range separates the grades that matter for health.
The Poseidon guide to MERV 11 versus MERV 13 puts the fine-particle numbers side by side. It reports that MERV 11 catches about 20 percent of particles between 0.3 and 1 micron, and that MERV 13 catches at least 50 percent of the same range. Smoke and the aerosol droplets that carry germs both fall in that band. That gap is why a household upgrades.
Every MERV grade costs some airflow, and the five inch cabinet is what makes MERV 13 workable. A one inch panel packs MERV 13 efficiency into a small face area. Five inches of pleat depth spreads it across several times the media surface. A household that stayed at MERV 11 for a thin filter slot has room to move once a media cabinet goes in.
Poseidon sorts each grade into its own collection. The MERV 8 collection handles dust and lint, and the earlier guide to MERV 8 filter sizes works through that grade in detail. Pollen and pet dander are the case for the MERV 11 collection. Fine particles are the case for the MERV 13 collection.
How Often a Deep Media Filter Needs Replacing
No Poseidon product page publishes a replacement interval, because the cabinet manufacturer sets it. General practice across the industry puts a five inch or six inch media filter on a six to twelve month cycle. A one inch panel usually gets 60 to 90 days. More media means more capacity before the pleats load up.
Several conditions shorten that window. Multiple pets, heavy pollen seasons, wildfire smoke and an ongoing remodel all load a filter faster than an average household does. A higher MERV grade loads faster too, because it is catching more.
Check the cabinet manufacturer documentation before setting a schedule. The manual for the specific cabinet model gives the number that applies to the equipment in the house. A 2 Pack then covers a full year at a six month cadence, or two years at a twelve month cadence.
Set the Reorder on Subscribe and Save
A deep media filter fails quietly. Nobody hears a loaded pleat pack, and six to twelve months is long enough for the date to slip. The filter keeps working at falling efficiency while the blower works harder against the load.
Subscribe and Save runs on every deep media product page. The program applies a standing 5 percent discount to every recurring shipment. The plan runs these filters on one of three intervals: three months, six months, or a year. The six month and twelve month options match the deep media window, so the schedule can follow whatever the cabinet manual calls for.
The Honeywell 20x25x5 Furnace Filter MERV 13 2 Pack runs $89.99 as a single order and $85.49 on a plan. The next 2 Pack then arrives before the current filter loads up, and the subscription removes the one step that actually breaks: remembering.
When the Number on the Old Filter Has No Match
Some searches return nothing, and 16x26x5 is the clearest example. A search across all 716 products on the Poseidon site returns zero results for that string in any MERV grade.
That result usually traces to one of two things. The number may have come off a tape measure laid across the cabinet opening. The filter in hand may belong to a cabinet brand Poseidon does not stock.
Work the problem in order.
- Read the nominal size printed on the old filter frame, and ignore any number taken from a tape measure.
- Find the cabinet model number on the door label, because that model number identifies the filter the cabinet takes.
- Call Poseidon Filters at 855-789-3278 with the model number in hand, and a filtration specialist will confirm the stocked size.
Guessing a close size is the one approach worth avoiding. A filter an inch off in either face dimension either refuses to seat or leaves a gap at the gasket, and air takes the gap every time.
Frequently Asked Questions
Does a 20x25x5 MERV 13 filter restrict airflow?
Less than a one inch panel at the same grade. Five inches of pleat depth spreads the media across a much larger surface area. That larger area lowers the resistance the blower faces. The furnace or air handler manual lists the maximum rated filter resistance for the equipment, and that figure settles the question for a specific system.
How much does the MERV 13 upgrade add on a 20x25x5 2 Pack?
On the Honeywell cabinet, MERV 13 runs $89.99 against $79.99 for MERV 8, a difference of $10.00 on the 2 Pack. On the Air Bear cabinet, MERV 13 runs $95.99 against $59.99 for MERV 8, a difference of $36.00. Both prices came off the Poseidon catalog on August 23, 2026.
What is the difference between the Honeywell and Air Bear 20x25x5 filters?
Both fit a five inch cabinet at the same nominal size, and they differ in frame construction and price. Honeywell filters suit cabinets with the Honeywell label. Poseidon lists the Air Bear filters as a compatible version for Air Bear cabinets. Read the label on the cabinet door and buy to match it.
Does Poseidon carry a 16x26x5 filter?
No. That size returns zero matches across the full Poseidon catalog. Read the nominal size printed on the old filter frame, then call 855-789-3278 with the cabinet model number, and a filtration specialist will identify which stocked size fits.
Find the Size, Then Pick the Grade
Deep media filtration turns on two numbers and one label. The nominal size on the old filter frame narrows the choice to one row on the grid above. The brand on the cabinet door narrows it to one product page. From there the MERV grade is the only open decision left.
Go straight to the Honeywell 20x25x5 Furnace Filter MERV 13 2 Pack for a Honeywell cabinet, or browse the MERV 13 collection for another stocked size. Set the Subscribe and Save interval to match the cabinet manual and the reorder handles itself.
Reviewed by the filtration specialists at Poseidon Filters, who match residential and office systems to the correct filter sizes every day.