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Why I paid more for an air purifier

Four brands in twenty years. I paid for the service, not the airflow, and I checked what other owners think of that.

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I have run air purifiers at home for more than twenty years: Sharp, then Philips, then Xiaomi, and now Dyson. Today I have one Dyson Big+Quiet (BP04) in the master bedroom and two Dyson HushJets.

The Dysons cost a lot more than the alternatives. This page is my honest answer to “why?”, followed by what Reddit owners and independent testers say. They mostly say I overpaid for the cleaning power. On that point they are probably right, and I explain below why I would still buy the same again.

Each brand gets one row: what I used, what happened and what I decided. The looking back lines compare my experience with what other owners report.

four brands, twenty years

  • first
    keep it simple

    Sharp

    used
    A small Sharp unit. Cheap filters, no Wi-Fi, only enough for a small room.
    decided
    Good enough that my parents still use it today.
    looking back
    The longest-lasting machine I have owned. Simple was not a weakness.
  • next
    a bigger name

    Philips

    used
    It worked for a while. After a few years the motor died, and I had never felt fully convinced by it.
    decided
    Let it go.
    looking back
    I found no pattern of Philips motor failures online, and Reddit owners rate the brand well. My unit may just have been unlucky. The common Philips complaint is different: some models stop running when the filter is due.
  • then
    budget and smart

    Xiaomi

    used
    Very good for the money. The Wi-Fi app was the problem: buggy and laggy.
    decided
    Good machine, weak app. The app started to matter to me.
    looking back
    Xiaomi’s own help pages cover units going offline and failing to pair, so I was not alone. Still, I found no sign that owners rate its app worse than Dyson’s overall.
  • NEX, Serangoon
    a demo, not an ad

    How Allan changed my mind

    did myself
    At Dyson’s NEX store, Allan showed me their vacuum cleaners. His demonstration convinced me, and I bought a Dyson vacuum at about double the price of comparable Chinese brands.
    decided
    One good experience led to the next: a wet-floor cleaner, then the Big+Quiet, then two HushJets.
    looking back
    The person in the store did more to win me than any spec sheet. I found almost no Reddit owners saying a demo won them over, so this part may be unusual.
  • Oct 2026
    what I own now

    One Big+Quiet, two HushJets

    did myself
    When one unit had a problem, Dyson sent me a brand-new machine.
    decided
    Staying with Dyson, mainly for the service and the app.
    looking back
    The weak spot: I am paying a lot for clean air that a cheaper unit could also give me. I would rather say so here than pretend otherwise.

the gas a filter can’t catch

The “Formaldehyde” in my Big+Quiet’s full name was new to me, so I read up. The essentials, in my own words, from Dyson Singapore’s explainer:

  • what it is

    A colourless gas. It comes off pressed-wood furniture (plywood, fibreboard), insulation, paint, wallpaper, varnish and some cleaning products. That new-furniture or fresh-paint smell is a sign something is being released.

  • why it lingers

    It keeps “off-gassing” long after the smell fades. A 2019 Chinese industry white paper put it at three to fifteen years after a renovation. A well-sealed home holds it in.

  • how common

    The same 2019 paper found half of Chinese homes above the 0.10 mg/m³ limit. A UK study that year found one in five of 47 homes at more than double the safe level. The US CDC says almost every home has small amounts.

  • what helps

    Choose low-formaldehyde furniture and paint, open the windows when you can, and use purification. The gas molecule is far too small for a HEPA filter to catch on its own.

  • Dyson’s claim

    The Formaldehyde models use a solid-state sensor that Dyson says won’t dry out the way gel sensors can, and a catalytic filter that breaks the gas down into water and CO₂ and never needs replacing. These are Dyson’s own claims. I found no independent test of them.

Why it matters to me: in Singapore, many of us renovate and then live with the windows shut and the aircon on. A fresh HDB renovation is exactly the case this describes.

Source: Dyson Singapore newsroom, “Formaldehyde: the invisible indoor pollutant”, which cites the CHEARI Chinese Home Indoor Formaldehyde White Paper (2019), Airtopia for Clean Air Day (2019) and the US Centers for Disease Control and Prevention. Credit to Dyson for the explainer.

what other owners say

From Reddit (r/AirPurifiers, r/dyson, r/asksg) and independent testers, checked in October 2026. Where I disagree, I say why.

  • value

    “You pay for the design”

    they say
    The loudest view by far. On r/AirPurifiers most replies say neither the BP04 nor the HushJet is worth the money, because Coway, Levoit and Winix clean as much air for much less. HouseFresh, an independent tester, says the same about both models.
    my take
    Fair. I didn’t buy on airflow per dollar, and nobody should buy a Dyson for that.
  • coverage

    Smaller rooms than the box suggests

    they say
    Tests put the Big+Quiet at a room of about 28 m², well below Dyson’s “up to 100 m²”. Dyson uses its own test method, not the standard one. The HushJet suits about one bedroom.
    my take
    Worth knowing before deciding which room each unit goes in. One HushJet owner in a 4-room HDB flat said it couldn’t keep the whole flat clean in the October haze. One post proves little, but one small unit for a whole flat is asking a lot.
  • noise

    Quiet, mostly

    they say
    Both are among the quietest at their size. A few HushJet owners report a buzz or whine within weeks.
    my take
    Matches my bedroom experience. A few complaints is too few to call a pattern yet.
  • app

    Usable, with one gap

    they say
    Most owners call it fine. The one specific complaint: on the HushJet, history logging drops out when the fan speeds up, and the graphs can’t be zoomed.
    my take
    Smooth for me, and the main reason I pay more.
  • sensors

    Nobody has tested them properly

    they say
    Split between “pretty decent” and “a gimmick”. I found no published test of either model against a reference air monitor.
    my take
    My units agree with each other, which shows they are consistent. It doesn’t prove they are accurate: they could all be off by the same amount. A side-by-side test with a separate monitor would settle it.
  • filters

    Cheap per year, if the claims hold

    they say
    Dyson rates its filters for years, so the cost per year can beat rivals. The HushJet is only about a year old, so nobody has proven that yet. Some markets report stock shortages. Third-party filters for these two models are scarce and untested, and Dyson says genuine filters protect the guarantee.
    my take
    Worth checking your warranty terms before using compatible filters.
  • service

    Mixed, depending on country

    they say
    Reviews from Europe range from slow repairs to fast replacements. I found no Singapore accounts at all.
    my take
    So mine is one data point: a new unit, no argument. That is the reason this page exists.
  • HushJet

    Too new to judge

    Fewer than about twenty owner reviews and one full lab test. Treat anything about its reliability, mine included, as early.

if you are choosing one

  • clean air only

    Buy for room size and filter cost. A Coway, Levoit or Winix does the job for much less.

  • app and service

    If tracking the readings and being looked after matter to you, my choice makes sense. Try the store and the app before you buy.

  • haze season

    Size the unit for the room, not the flat. One small purifier won’t clean a whole HDB flat with the windows leaking.

  • name the weak spot

    Mine is price. Writing it down keeps me honest about it.

Other decisions written up the same way: a year of hi-fi decisions, and a laptop I bought twice.

the details

Tested room size, in numbers
ModelClean air deliveredRoom it suitsNoise
Big+Quiet (BP04 family)about 190–200 CFMabout 28 m²33–51 dB
HushJetabout 160 CFMabout 17–22 m²35–53 dB

From HouseFresh’s tests (Big+Quiet BP06, same body as the BP04; HushJet, 20 Oct 2026) and figures quoted from RTINGS. Room sizes assume about five air changes an hour.

Sources, and how much to trust them

Reddit blocks automated reading, so only a handful of threads were read in full. Treat the Reddit views here as anecdotes, not a survey.