NestyFinds

Blueair Blue Pure 511 vs Winix 5500-2: how much purifier do you need?

By the NestyFinds editorial team · Researched from manufacturer documentation, manuals and the AHAM Verifide directory · not bench-tested · Reviewed:

This is not really a contest between two rivals — it is the question of whether you need twice the machine. Both are AHAM Verifide, so for once the headline numbers are measured the same way by the same body, which makes the trade unusually clean to read: roughly half the clean air for roughly a quarter of the power.

Side by side

Spec Blueair Blue Pure 511 Winix 5500-2
CADR — smoke 122 cfm 239 cfm
CADR — dust 123 cfm 244 cfm
CADR — pollen 123 cfm 247 cfm
AHAM Verifide Yes Yes
Coverage 189 ft² 370 ft²
Coverage stated at 4.8 air changes per hour. Blueair publishes "Air changes per hour (ACH): 4.8" in its own Technical Specifications table alongside the 189 sq ft figure — one air change every 12.5 minutes, which matches Blueair's "Quickly cleans 189 ft² in 12.5 minutes" headline and reconciles with AHAM's 189 sq ft listed room size at 122 cfm smoke CADR. The same page separately claims "up to 413 ft² in 30 minutes", which works out to roughly 2 ACH and is a different, weaker basis. 4.8 ACH. AHAM's directory states suggested room size is "always based on the air cleaner's ability to clean and circulate the air in the room 4.8 times per hour", using Room Square Feet = Smoke CADR x 1.55. Check: 239 x 1.55 = 370. This formula is AHAM's universal calculation for every Verifide model, not a per-product choice by Winix.
Filter stages Washable outer fabric pre-filter · HEPASilent electrostatic particle charging — Blueair describes the technology as combining "electrostatic and mechanical filtration" · Particle filter layer — Blueair claims it removes 99.97% of airborne particles down to 0.1 micron · Activated carbon layer, rated by Blueair for "light household odors from smoke, cooking odors and more" Pre-Filter · Washable AOC Carbon Filter · "True HEPA Filter" · PlasmaWave Technology
Filter life 6 months 12 months
Noise range 24–49 dB Not published
Max power 16 W 70 W
CARB certified Yes Yes

“Not published” means the manufacturer does not document that figure for this model. We leave it blank rather than borrow the number from a sibling model — which is how most comparison tables end up wrong.

Criterion by criterion

So which one?

Choose the Blueair Blue Pure 511

One bedroom-sized room, up to roughly 190 sq ft, and you want it running continuously without noticing it on the electricity bill — and you accept a 6-month filter schedule and an electrostatic stage you cannot switch off.

Full review

Choose the Winix 5500-2

A living room, an open-plan space, or anything over about 200 sq ft — or you want twice the measured clean-air output and an annual rather than six-monthly filter, and the higher power draw is not what decides it for you.

Full review

Price, seller and package contents change. Check the variant on Amazon before you buy.

How we researched this

Checked against the AHAM Verifide directory, CARB's certified air-cleaner list, the ENERGY STAR certified-products list and the manufacturer's own pages. We did not test this unit. Nothing here is a measurement of ours: every figure is either documented by the manufacturer or published by an independent standards or testing body, and where the two disagree this page says so.

Sources consulted