Independent scores, with our math shown
Air purifiers and water filters, scored on proof - not marketing.
You want to know what actually works before you buy. We score air purifiers, water filters, and furnace filters against published specs and real standards - then work out the one number sellers leave off the box: what the thing truly costs you to own once you count the replacement cartridges.
What five years actually costs
Air purifiers, cheapest to own first. Device plus every replacement cartridge, from dated prices.
- 61
- products scored
- 69
- certifications confirmed
- 28
- with none we could find
Certifications are the ones we could confirm on the public NSF, WQA, IAPMO, AHAM and CARB registries. A brand's own "tested to" claim never counts as one.
Air purifiers
See allRanked by composite score
- 8.5Coway Airmega AP-1512HH MightyAHAM-verified, true sealed HEPA, cheap to run, defeatable ionizer with CARB-certified negligible ozone. The honest benchmark.
- 7.1Levoit Core 300SA compact smart HEPA purifier for bedrooms and small-to-medium rooms with app and voice control.
- 7.1Levoit Core 400SA higher-output smart HEPA purifier for large living rooms with an air-quality sensor and auto mode.
Water filters
See allRanked by composite score
- 8.4Brita Elite Pitcher (10-Cup)A pour-through pitcher whose Elite filter is certified to reduce lead, mercury, cadmium and more, with a long 120-gallon cartridge.
- 7.5AquaTru Classic Countertop ROA no-plumbing countertop 4-stage RO purifier certified to NSF standards for lead, PFAS, fluoride and arsenic with an efficient drain ratio.
- 7.5Culligan US-EZ-4 Under-SinkAn under-sink filter genuinely IAPMO certified to NSF/ANSI 42, 53 and 401 for lead, cysts, VOCs, mercury and PFOA/PFOS.
Furnace filters
See allRanked by composite score
- 6.0Aprilaire 213 (4-inch media, MERV 13)A 4-inch whole-house media filter, true MERV 13, replaced about once a year. Deep media means high filtration with minimal airflow restriction - the technically right way to run MERV 13. Aprilaire publishes the ASHRAE 52.2 test method and a per-model static pressure drop (0.15 in. w.c. at 1200 CFM).
- 6.0Aprilaire 413 (4-inch media, MERV 13)The same MERV 13 deep media as the 213 in a different cabinet size. Honest MERV labeling, low airflow restriction, annual replacement. Aprilaire publishes the ASHRAE 52.2 test method and a per-model static pressure drop (0.17 in. w.c. at 1200 CFM).
- 6.0Honeywell FC100A1037 (4-inch media, MERV 11)A 4-inch media filter labeled MERV 11 (this OEM line uses MERV, not FPR). We hold it at Partial: Honeywell's own F100 datasheet is self-contradictory - the cover and parts list say MERV 11, but the efficiency table on the same sheet lists this part as MERV 10. Deep media, low airflow restriction, yearly replacement.
The distinction the whole site turns on
A claim is not a certification
If you remember one thing before you shop, make it this: "tested to NSF standards" is not the same as "NSF certified." The first is a lab result a brand paid for once; the second is an audited program you can look up yourself in a public database. That gap is exactly why a filter you've seen everywhere can land near the bottom of our list.
When a brand says "tested to" a standard instead of "certified to" it, or hides its real MERV behind a number it made up, we tell you plainly.
Read the guideStart here
All guidesCADR explained
How to pick a purifier that can actually keep up with your room - and why the coverage on the box is usually inflated.
PFAS in drinking water
What the EPA's 2024 limits mean for you, and which certifications actually get PFAS out of your tap.
Water quality by state
What's documented in your state's water, matched to the filters certified to deal with it.