Editorial methodology
Fit first. MERV second.
FiltersFit.com first establishes what can physically fit, then compares filtration and retailer options. A rounded size label alone never becomes a compatibility guarantee.
Nominal label and actual dimensions are different facts
Nominal size is the category printed prominently on a frame, such as 20x25x5. Actual dimensions are the outside width × height × depth published by the manufacturer or printed in smaller type. Several physical profiles can share one nominal label.
We preserve the published order and precision. A small difference is not rounded to the nearest profile because cabinet rails, gaskets, and insertion direction can make it meaningful.
Four ways the 20x25x5 guide checks fit
- Part number (SKU). Exact manufacturer model, compatible part number, merchant SKU, or UPC matches are placed first.
- Printed actual size. The full three-dimensional value selects only the corresponding physical profile.
- Measured filter. The user measures outside edge to outside edge; unmatched values are not silently corrected.
- Label only. The guide shows all products as “Same listed size” and asks the user to confirm the actual size before buying.
Evidence levels used in fit messages
Documented match
A manufacturer manual, datasheet, or product page directly connects a cabinet, replacement model, or part number to the filter.
Dimensional match
Published width, height, and depth match in the same order. This is strong physical evidence, but not a manufacturer cabinet claim.
Nominal match
Only the rounded label matches. It is a browsing category—not proof that two filters share the same outside dimensions.
Needs evidence
The available label, measurement, or code is incomplete or does not map cleanly to a documented profile.
Known mismatch
At least one required dimension or documented relationship conflicts. We do not show a merchant purchase action for that result.
What sources can establish
Manufacturer manuals, datasheets, technical tables, and product pages can support dimensions, part-number relationships, filtration ratings, and system compatibility. Retailer pages support a specific offer’s identity, pack, destination, displayed price, and availability; they do not create a manufacturer compatibility claim.
Every public technical claim should retain a source URL and checked date. Product evidence on the 20x25x5 guide links back to those sources.
Fit profiles, product variants, and packs
A Fit profile represents one exact width × height × depth combination. A Product variant represents a distinct filter specification such as brand, model, actual dimensions, and MERV. Available pack quantities are listed inside the product card, not treated as separate products.
Offers from different sellers are merged only when UPC/GTIN, manufacturer model, or part number makes the identity unambiguous. When the evidence is uncertain, they remain separate.
How catalog snapshots and prices work
The catalog is built from the latest scraper snapshot that passes validation. Only records with known actual dimensions and MERV are published. The snapshot supplies the visible one-time pack price, calculated price per filter, availability, pack choices, and exact retailer destination.
Subscription pricing is not treated as the main price. Out-of-stock options do not receive an active purchase link. Because the scraper is a periodic snapshot rather than a guaranteed continuously updated feed, price and availability are not yet emitted as Product or Offer structured data.
How products and retailer options are ordered
Fit evidence is applied before any commercial comparison. An exact SKU match is shown first; dimensional matches remain within the selected profile. Inside an equivalent result set, users may sort by price, MERV, retailer, or pack.
Affiliate and unaffiliated destinations are identified in link data. Commission size does not affect product ranking, and an outbound click is not treated as a purchase.
Why MERV comes after fit
MERV describes particle-capture efficiency under a standard test; it does not describe physical fit or the resistance of every product with that rating. We compare airflow data only when SKU-level values use comparable test conditions, and we do not present FPR or MPR as exact MERV conversions.
Limits and manual review
- FiltersFit.com does not diagnose, inspect, or repair HVAC equipment.
- A higher MERV rating is not automatically right for every system.
- Displayed retailer price and availability can change after the snapshot was collected.
- The planned standard price for a manual fit check is $20. During early validation, the first requests are free and the guide collects only an email so we can arrange the next step.