Head-to-head comparisons

NSF-certified lead and PFAS reduction vs 'tested to' lab claims with no certification. Side-by-side, including cost per gallon.

Two certified pitchers compared. Both are certified for lead and PFOA/PFOS; the real difference is running cost - ZeroWater's 15-gallon filter is far costlier per gallon than the Brita Elite's 120-gallon filter.

Same brand, very different certifications. The Elite filter is certified for lead and PFAS; the Standard filter is not.

A long 'tested to' contaminant list with no active certification vs a pitcher genuinely certified for lead. A case study in claims versus proof.

A pitcher lab-tested to NSF standards for fluoride, lead, and PFAS vs one genuinely NSF-certified for lead. Tested to is not certified to.

365+ 'tested to' contaminant claims vs a handful of genuine NSF certifications. A case study in tested-to versus certified-to.

Countertop no-plumbing RO vs a tankless under-sink RO. Compared on certified contaminants, cost per gallon, and wastewater.

A no-plumbing countertop RO vs a cheap-to-run under-sink carbon filter. Both certified for lead and PFAS - compared on cost per gallon and certified scope.

Two genuinely certified under-sink carbon filters compared on certified contaminants, cost per gallon, and install.

Same brand, two formats. Both certified for lead; compared on cost per gallon, flow, and convenience.

ZeroWater is certified for lead and PFOA/PFOS; Brita is not. But Brita runs at $0.20/gallon vs ZeroWater's $1.17. See how we score both.

Both 7-cup pitchers cost $24.99, but PUR Plus runs $0.374 a gallon vs ZeroWater's $1.167 - and a 40-gallon filter vs just 15.

AquaTru holds IAPMO certification for lead, PFAS and fluoride. Big Berkey has no accredited certification. We score AquaTru 7.5 to Big Berkey's 3.2.

Waterdrop is IAPMO-certified for lead, PFAS and arsenic; the cheaper APEC ROES-50 is certified only for TDS and markets lead it isn't certified for.

Two under-sink RO systems certified for TDS only. The iSpring runs about $0.024 per gallon vs $0.145 for the APEC - a 6x gap in running cost.

The RCC7 holds one NSF/ANSI 58 certification for TDS; the RO5DX has no accredited certification at all. We score both and explain the gap.

ZeroWater holds NSF/ANSI 53 certification for lead and PFOA/PFOS; Clearly Filtered is certified only for chlorine. We score both.

The AQ-5200 holds WQA certification for PFOA and PFOS; the Epic Smart Shield markets PFAS removal without a certification for it. We score both.

Brita Elite holds PFOA/PFOS certification and runs $0.167 a gallon; the PUR Plus has neither and costs $0.374. See our full scoring.

Two million-gallon whole-house carbon filters with no system certification. The CF1 is marketed for lead and PFAS it isn't certified to remove.

The Frizzlife SK99 is IAPMO certified for lead and VOCs; the Waterdrop 10UA is certified for chlorine only. See how they score.

The Waterdrop holds IAPMO certification for 14 contaminants including lead and PFAS; the Home Master holds none. See how we score both.

The AQ-5200 holds WQA certification for lead and PFAS; the Clearly Filtered carries none and costs $350 more up front. See how we score both.

Both certified for lead, both 100-gallon cartridges. Brita runs about $0.18 a gallon to PUR's $0.25; certified lists differ.

Same brand, two formats. The Elite adds certified PFOA/PFOS; the faucet mount filters on demand and adds certified VOCs.

One carries a WQA certificate you can look up. The other says 'Certified to NSF/ANSI 42&53' but names no certifier or registry.

APEC holds one WQA certificate, for TDS; we found none for the RO5DX. Running cost splits the other way: $0.021 vs $0.145.

AHAM-verified sealed HEPA vs a budget unit with no AHAM CADR listing and an overstated room-size claim. Side-by-side FilterScored breakdown.

The two most popular budget air purifiers, compared on AHAM-verified CADR, ozone safety, and annual filter cost.

Two medium-room favorites compared. The Winix adds a washable carbon filter but ships with a PlasmaWave ionizer.

A large-room value pick vs a high-output flagship. Compared on AHAM CADR, honest coverage, and filter cost.

A 299-dollar mainstream large-room unit vs an 845-dollar steel-housing purifier. Compared on annual filter cost, ozone safety, and verified HEPA.

A 900-dollar premium unit vs a 230-dollar mainstream one. A clear illustration of how FilterScored weights verified data and running cost.

A 650-dollar fan-purifier vs a 230-dollar dedicated purifier. Compared on verified CADR, room coverage, and filter cost.

Both score 7.1/10 in our scoring. The 400S verifies 259 cfm CADR for 358 sq ft; the 300S is smaller, cheaper to run at $45/yr.

The AP-1512HH has an AHAM-verified CADR and a sealed HEPA system; the 200M is unverified and uncertified. We score it 8.5 vs 3.5.

The Winix 5500-2 ships an ionizer that we floor on safety; the Levoit Core 400S runs ozone-free. See how we score both on verified data.

The Levoit uses a true H13 HEPA filter; the Blueair is HEPA-type with an always-on ionizer you cannot switch off. See our scores.

Same 246 cfm AHAM-verified CADR, but the AM90 costs $100 a year in filters to the 5500-2's $55. See how we score both.

The Coway's 400 cfm CADR is AHAM-verified; the pricier IQAir's CADR is not. Five-year costs run $1,294 vs $1,874. See how we score both.

The Coway runs at about $36 a year versus the Medify's $120, and scores 8.5 to 5.9 in our rubric. See the five-year cost gap.

The 211+ is HEPA-type, not true HEPA, and costs $118/yr to run; the Core 400S uses an H13 filter at $75/yr. See how we score them.

The $230 Coway is AHAM-verified and runs $36 a year; the $599 Rabbit Air has unverified CADR and a flagged room claim. We score both.

The $230 Coway has AHAM-verified CADR and runs $36/year. The $1,000 Molekule has no verified CADR and costs $350/year in filters.

The Coway claims 1,560 sq ft its AHAM CADR cannot deliver and we hard-fail it; the Alen carries a defeatable ionizer. See how both score.

The Levoit's AHAM CADR honestly covers its 219 sq ft claim; the GermGuardian's CADR supports about 190 sq ft, not the 743 it markets.

Both cost about $149 up front, but the MA-25 runs $150/yr in filters versus $45/yr for the Core 300S. See how we score the five-year gap.

Two Dyson H13 purifiers, near-identical scores. The BP03 claims 1000 sq ft but its CADR backs far less. See which we score higher.

Same brand. The 400 moves more air, but its 1,560 sq ft claim really covers about 620 sq ft, on $129/yr filters.

Both AHAM-verified, both medium-room. The Winix ships a PlasmaWave ionizer with no CARB listing; the Levoit has none at all.

A famous 1-inch filter sold by a proprietary MPR number vs honest 4-inch MERV 13 media. Both are MERV 13 - the difference is labeling and airflow.

Two 1-inch MERV 13 filters. One markets a proprietary MPR number at a premium; the other prints true MERV 13 for a fraction of the price.

The MPR 1900 is true MERV 13, the 1500 is MERV 12. In our scoring the lower-MERV 1500 wins on airflow fit in a 1-inch panel.

Both are true MERV 13 in a 1-inch panel. The Filtrete runs about $92 a year vs the Honeywell's $108. See how we score them.

Both 1-inch pleated filters score 5.9/10. The split: true MERV 13 with more airflow restriction vs true MERV 12 at the honest baseline.

Same MERV 13 deep media, same $65 a year, same 6.0 score. The only published difference is cabinet size and static pressure drop.

Two honest 1-inch pleated filters at 5.9/10. Nordic Pure is true MERV 12, Amazon Basics true MERV 11. We split the pick by filtration need.

Two 4-inch furnace filters tied at 6.0/10. The Aprilaire is true MERV 13; the cheaper Honeywell is MERV 11. We compare honestly.

True MERV 11 at about $36/yr vs true MERV 13 at about $65/yr. Both honestly rated. We score both 6.0/10. How to pick.

MPR 1500 is MERV 12 on the standardized scale; the Aerostar is a true MERV 13 at under half the yearly cost. Both 1-inch.

A 1-inch MPR 1500 (true MERV 12) swapped quarterly vs 4-inch MERV 13 media changed yearly. They need different slots.

Two 1-inch filters, both true MERV 13. One is sold as 'FPR 10' at about $108 a year; the other prints MERV 13 and runs $35.

A 4-inch MERV 11 media cartridge changed yearly, about $39, vs a 1-inch MERV 13 panel changed quarterly, about $92.

The fiberglass throwaway costs about $92 a year at monthly changes; the pleated MERV 12 runs about $39 and captures far more.