Dyson Purifier Big+Quiet Formaldehyde BP04

Dyson’s largest purifier: CARB lists it as mechanical, RTINGS measured 193 cfm at 33 to 48 dBA, and Dyson calls it fully sealed. It gives no CADR or lab reports. About $900 on sale, $1,199.99 list. We have asked Dyson for the reports.

Best for A buyer who wants Dyson’s design, quiet running and its catalytic formaldehyde filter, and accepts a medium-room CADR at a premium price.

Our rating: Fair (3.2 of 5)
Price range: Premium
Verified marks: Listed by CARB as a mechanical air cleaner (BP04 YY and BP04 ZZ)
Size: Floor unit, 26.2 lb, 32.7 in tall; Dyson’s US page gives no room rating or CADR, and RTINGS measured about 193 cfm, a room of about 300 sq ft

approx. $900 on sale (list $1,199.99)

See it on Dyson’s site → (opens in a new tab)

We are not affiliated with Dyson. This link goes to the maker’s own page, with no tracking code. How we're funded.

Also sold at Bloomingdale's ($1,200), Macy’s ($1,200) .

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How we evaluated it

How it scores Our rating, metric by metric Fair, 3.2 of 5

Filtration 30% of the rating 3 of 5

Dyson publishes no CADR and AHAM has no Dyson entry, so the only figure is RTINGS’ measured 193 cfm, and its 99.97% HEPA figure names no lab.
Adds nothing to the air 20% of the rating 4 of 5

CARB lists it as mechanical (order G-23-113), but we found no independent test of what its catalytic formaldehyde stage and potassium carbonate filter give off.
Independent testing 20% of the rating 4 of 5

RTINGS tested this exact model and Consumer Reports and HouseFresh tested its sibling models, all with no Dyson money, but nobody has tested its formaldehyde or virus claims.
Trust 10% of the rating 3 of 5

We found no purifier recall and no purifier lawsuit, but its two filter-life statements disagree, its HEPA, formaldehyde and virus tests name no lab, and Dyson has not published a CADR.
Running cost & value 20% of the rating 2 of 5

At today’s $899.99 sale price a measured 193 cfm is about $4.7 per CFM and about $7.0 over five years with Dyson’s filters, against $0.86 and $2.4 for the Levoit 500X; at the $1,199.99 list price it would score 1.

The rating, 3.2 of 5, is the weighted average of these scores. See how we rank air purifiers and our standard.

Where to buy Stores and the prices we saw 2 stores

Bloomingdale's (opens in a new tab) approx. $1,200. Prussian Blue/Gold, the BP04 itself. Sold and shipped by Dyson, at the $1,199.99 list price while Dyson’s own site showed $899.99. Best Buy, Home Depot and Amazon sell the BP03, a different model.
Macy’s (opens in a new tab) approx. $1,200. Prussian Blue/Gold, the BP04 itself. Shipped and sold by Dyson, at the $1,199.99 list price. RTINGS says the BP04 is exclusive to Dyson’s online store, which these two department stores appear to list on Dyson’s behalf.

Prices as we saw them on October 23, 2026. They change often. These links carry no tracking code and earn us nothing.

What it’s made of What touches your food, water, skin or air 4 materials

H13-grade HEPA filter in a cylinder (what the fiber is made of is not stated)
K-carbon filter: an activated carbon sheet impregnated with potassium carbonate, which Dyson says adsorbs more nitrogen dioxide (carbon weight not stated for the BP04)
A permanent catalytic (SCO) filter that Dyson says breaks formaldehyde down into water and carbon dioxide
Sealed plastic housing with a bladeless fan, sensors including CO₂, and an LCD (resin types not stated)

Who tested it What each test found, and who paid for it 5 tests

Independent RTINGS (buys its test units; earns membership and affiliate income) May 13, 2024

Tested the BP04: a measured PM1.0 CADR of 193 cfm (329 m³/hr) at top speed, a recommended room size of about 302 sq ft, and noise of 33.4 to 47.6 dBA. Calls the CADR good but not great, and lists the H13 HEPA filter as certified. Open ↗ (opens in a new tab)
Independent HouseFresh (buys its test units; earns affiliate income) December 17, 2025

Tested the cheaper BP06, which RTINGS says has the same three-stage H13 system and a simpler control set: an estimated PM1 CADR of 198 cfm, 40.4 to 51.4 dBA, 33 W at top speed. It lists an AHAM PM2.5 CADR of 190.8 cfm for the BP06 and says the BP03 and BP04 are harder to justify on price because they are not nearly as powerful as machines costing as much. Open ↗ (opens in a new tab)
Independent Consumer Reports (nonprofit; buys what it tests; summarized by SlashGear)

Lab-tested the BP03, the same machine without the CO₂ sensor and K-carbon filter: an overall score of 69 and good particle removal, enough for a recommendation, but at a price well above machines with higher scores. CR’s own ratings are members-only. Open ↗ (opens in a new tab)
Paid certification CARB (certification; Dyson pays the lab) May 10, 2023

Listed as Mechanical (BP04 YY and ZZ, order G-23-113), so it passed the state’s ozone limit. It says nothing about particle removal. Open ↗ (opens in a new tab)
Maker’s own test Dyson (maker)

Says an unnamed third party tested the whole machine for formaldehyde to GB/T 18801-2022, PM2.5 purification was tested in a large chamber by Dyson’s methods, and the HEPA filter was challenged with DEHS oil to EN 1822 in an ASTM F3150 chamber. It names no lab and publishes no result. Open ↗ (opens in a new tab)

Who paid, and why it matters

Independent The tester took no money from the maker for it: a consumer group, a journalist, a university or a regulator.
Paid certification An outside lab or certifier tested or listed it, and the maker paid for that.
Maker’s own test A lab report or certificate of analysis the maker commissioned and published.

A certification is a floor, not a verdict: it checks what its program checks and nothing else. We weigh tests by someone with no stake in the result most.

What people ask Worries raised online and elsewhere, and what we found 6 questions

Does the formaldehyde claim hold up?: Dyson says a third party tested the whole machine against GB/T 18801-2022 and that its catalytic filter breaks formaldehyde down for good, with “results may vary in practice”. No lab or result is published, and we found no independent test. Our guide notes that plain carbon adsorbs formaldehyde poorly, so treat the claim as unproven.
Is it worth $900 to $1,200?: RTINGS calls the CADR “good, but not great”, best for medium rooms, and says better-performing and cheaper options exist. HouseFresh (opens in a new tab) says the BP06 costs $600 to $700, is already priced like premium models, and that the BP03 and BP04 are harder to justify. Over five years with filters we count about $7.0 per CFM at today’s $899.99 sale price ($8.5 at list), against about $2.4 for the Levoit 500X.
Why does Dyson publish no CADR?: In a 2021 CBC Marketplace test (opens in a new tab) of an older Dyson combination heater, a Dyson engineer said the company wants to “pull back a little bit” from CADR and prefers its own POLAR method. The test was of a different Dyson model. AHAM’s directory lists no Dyson product, though HouseFresh reports an AHAM CADR certificate for the BP06.
Do Dyson fans develop noises?: A few Reddit users say so. In comments summarized by RedditRecs (opens in a new tab), one owner of other purifiers warns that Dyson fans tend to whistle or crackle after the warranty ends and calls the catalytic filter a gimmick unless you have a formaldehyde problem. The page counts only 4 users, 50% positive, so it is a small sample. We found no failure data for the BP04, and the warranty is 2 years. Consumer Reports’ brand charts, as SlashGear (opens in a new tab) summarizes them, give Dyson 3 out of 5 for owner satisfaction and for predicted reliability among air purifier brands.
Any recalls, lawsuits or notices?: None for its purifiers that we found. CPSC lists only a 2014 Dyson heater recall. The California AG (opens in a new tab) shows one 2015 Prop 65 notice, over phthalates in a Dyson vacuum tool kit. A 2023 class action over Dyson’s warranty terms (opens in a new tab) was dismissed in 2024.
Does the filter contain PFAS? Some HEPA media uses PTFE.: Dyson does not say what its HEPA media or housing is made of, and we found no published PFAS test of purifier filter media from any maker. We could not confirm either way.

Why we chose it What put it on our list 4 points

CARB lists the BP04 (variants YY and ZZ) as Mechanical (notified 2023-05-10, order G-23-113). By CARB’s definition that means filtration only, with no ozone or ions.
RTINGS bought and tested this exact model: a measured PM1 CADR of 193 cfm (about 300 sq ft by its rule), and noise of 33.4 dBA at the lowest speed to 47.6 dBA at the highest. That is a genuinely quiet machine for its airflow.
Dyson says an H13-grade HEPA filter, a K-carbon filter (potassium carbonate) and a permanent catalytic filter work inside a fully sealed machine. It names no lab for the 99.97% figure at 0.1 µm.
Parts and prices are published: HEPA filter $169.99 (replace every 5 years), K-carbon filter $109.99 (every 2 years), remote $29.99. That is about $89 a year if you follow Dyson’s intervals. The machine has a 2-year limited warranty.

Trade-offs What to weigh before you buy 4 points

Dyson’s US page gives no CADR, no room rating and no decibel figure. It says only that PM2.5 purification was tested in a large chamber by Dyson’s own methods. AHAM’s directory has no Dyson entry (searched 2026-10-23). RTINGS’ measured 193 cfm is the only figure for the two-thirds rule: about 290 sq ft.
Its list price is $1,199.99 and Dyson’s site showed $899.99 on 2026-10-23. At $899.99 that is about $4.7 per CFM, or $6.2 at list, against about $0.86 for the Levoit Eleva 500X. RTINGS and HouseFresh both say that for particles it does no better than machines costing far less. RTINGS says Dyson’s simpler BP06 has the same three-stage H13 system, without the K-carbon filter, and HouseFresh priced it at $600 to $700.
Dyson’s filter lives conflict. The product page says the HEPA filter lasts up to 11 years. The parts listing says to replace it every 5 years or when the app says so.
Dyson’s page makes claims about viruses, bacteria and formaldehyde, with qualifiers such as “results may vary in practice”. See what trials show about air purifiers. Not every Dyson purifier is filtration only: CARB lists several purifier-humidifier models (for example PH05 and PH4A) as Electronic.

What to know Details worth knowing first

The Big+Quiet is Dyson’s most capable purifier on paper: a HEPA filter, a carbon filter and a catalytic filter for formaldehyde, all inside a casing Dyson calls fully sealed. CARB files the BP04 as a mechanical cleaner, which is what our air purifier guide looks for. RTINGS bought one and found it very quiet, with a measured CADR of 193 cfm, enough for a medium room.

The trouble is what Dyson leaves out. It publishes no CADR, room rating or decibel figure, so the only way to check the room size is someone else’s test. The HEPA and formaldehyde tests are Dyson’s, from labs it does not name, and its two filter lives disagree. For formaldehyde in general, see formaldehyde.

At about $900 on sale, or $1,200 at list price, it costs far more than models with a verified CADR, and RTINGS and HouseFresh both say the particle performance does not justify the premium. It may suit you if you already like Dyson’s design and quiet. We are asking Dyson for a CADR and its test reports; until they arrive, its formaldehyde and virus claims stay Dyson’s own. If room size or price matters most, choose a model with a listed CADR.

What we checked Each claim, and how sure we are of it 5 checks

How Dyson Purifier Big+Quiet Formaldehyde BP04 measures up against our air purifiers criteria
What we checked	What we found
True HEPA Maker’s claim	Dyson says the filter is HEPA H13 grade and captures 99.97% of particles as small as 0.1 microns; RTINGS lists it as HEPA certified. The only test Dyson describes is for filter life (DEHS oil as in EN 1822, in a chamber built to ASTM F3150). No lab, no report.
No ozone (CARB listing) Verified	CARB’s list has Dyson BP04 YY and BP04 ZZ as type Mechanical, notified 2023-05-10, order G-23-113.
Right size (CADR) Verified	No CADR or room rating on Dyson’s US page, and no Dyson entry in AHAM’s directory (searched 2026-10-23). RTINGS measured a PM1 CADR of 193 cfm: about 290 sq ft by our two-thirds rule.
Carbon for gases Maker’s claim	A K-carbon filter (potassium carbonate, rated 2 years) and a permanent catalytic filter for formaldehyde, per Dyson. The amount of carbon and the formaldehyde result are not published.
Running cost and noise Maker’s claim	Dyson publishes HEPA $169.99 and K-carbon $109.99 with change intervals. RTINGS measured 33.4 to 47.6 dBA; Dyson gives only a night mode comparison.

What the labels mean

Verified We opened an independent record that confirms it: a certifier’s listing, a regulator’s list or a lab report. It is linked under Sources.
Maker’s claim The maker says so on its own page or label. We read it but found no independent record.
Not verified We looked and could not confirm it, or the maker does not say. Treat it as unknown.

Sources Where our facts come from 13 sources

Dyson Purifier Big+Quiet Formaldehyde BP04 product page. Maker’s page. Filter prices and footnotes as seen on 2026-10-23, and a price of $899.99 marked down from $1,199.99. Opens in a normal browser; dyson.com blocks automated fetches. Open ↗ (opens in a new tab)
RTINGS: Dyson Purifier Big+Quiet Formaldehyde BP04 and BP03 review. Test report. RTINGS tested the BP04 and says it is exclusive to Dyson’s online store. It buys its units and earns membership and affiliate income. Open ↗ (opens in a new tab)
Bloomingdale’s listing for the BP04 (Prussian Blue/Gold). Independent source. Price $1,199.99 on 2026-10-23, shown as sold and shipped by Dyson. Open ↗ (opens in a new tab)
HouseFresh: Dyson Big+Quiet Formaldehyde BP06 review. Test report. Tests the cheaper BP06, not the BP04. HouseFresh buys its units and earns affiliate commissions. Open ↗ (opens in a new tab)
SlashGear: major air purifier brands ranked, according to Consumer Reports. Independent source. A secondary summary of Consumer Reports’ BP03 result. CR’s own ratings page lists the BP03 but its scores are members-only. Open ↗ (opens in a new tab)
RedditRecs: Dyson BP04 on Reddit. Independent source. A third-party site that summarizes Reddit comments with software and earns Amazon affiliate fees. The samples are small. Open ↗ (opens in a new tab)
CBC Marketplace: is an $800 purifier best to clean your home’s air?. Independent source. 2021 University of Toronto test of an older Dyson combination heater, not the BP04. Includes a Dyson engineer’s comments on CADR. Open ↗ (opens in a new tab)
CARB list of certified air cleaning devices (search for Dyson). Certifier or regulator listing. BP04 YY and ZZ are type Mechanical (order G-23-113). The list is one long table with no link for a single model. Open ↗ (opens in a new tab)
AHAM Verifide directory (search for Dyson). Certifier or regulator listing. A search tool with no link for a single listing. A search for Dyson returned no listing on 2026-10-23. Open ↗ (opens in a new tab)
The Dyson Limited Warranty. Maker’s page. Lists a 2-year limited warranty for purifiers and humidifiers and for cordless vacuums. Open ↗ (opens in a new tab)
ClassAction.org: Castiel v. Dyson (warranty terms), dismissed. Independent source. Filed 2023-06-01, N.D. Ill. No. 1:23-cv-03477; dismissed 2024-02-13. Open ↗ (opens in a new tab)
California AG Prop 65 notice search: Dyson. Certifier or regulator listing. One notice, 2015-00572 (2015-06-17), over phthalates in a Dyson vacuum tool kit sold through Sears. Open ↗ (opens in a new tab)
CPSC recall search: Dyson. Certifier or regulator listing. Returned one recall on 2026-10-23: Dyson bladeless portable electric heaters, 2014. Open ↗ (opens in a new tab)

Alternatives Other options to compare 3 options

IQAir HealthPro Plus XE About $1,200, with a separate carbon cartridge and published filter prices. It also publishes no CADR; HouseFresh measured about 213 cfm on the older model.
Levoit Eleva 500X About $260, with an AHAM-listed smoke CADR of 301 and a CARB mechanical listing. It is new: Amazon lists it as first available on 2026-10-18, and no one has tested it yet.
Oransi Mod+ About $699, with an AHAM smoke CADR of 363 and a HEPA and carbon filter in one.

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