Xiaomi Smart Air Purifier 4 review
By Tom Calder
We no longer recommend this model, so it no longer appears in our buying guides. In its place, we now recommend Winix Zero-S Air Purifier in our Air purifiers guide.
Key specs
The maker's figures.
- Room size
- 48 m²
- CADR
- 400 m³/h
- Filter
- 3-in-1 filtration, removes 99.97% of 0.3-micron particles
- Noise (min)
- —
On paper this has the highest CADR on the whole list at 400 m³/h for a mid-range price, but it's also the least solidly sourced entry here — no confirmed UK ASIN and only an approximate price. Worth chasing down the exact BHR5101EN listing and a live price before treating this as a firm recommendation.
- Best for
- Buyers who want the highest published CADR for their money and are comfortable double-checking price and stock themselves
- Skip it if
- You want to buy with total price and listing certainty today
We earn a commission if you buy through the retailer links on this page. It doesn't change our verdict. How we make money →
Researched, not used. We haven't used this product. This review is built from the maker's specifications, owner reports and our own sizing.
What we like
- Highest published CADR on this list at 400 m³/h
- 99.97% particle removal at 0.3 microns, matching the True HEPA standard other brands use
- Compact 28–48 m² coverage suits most UK living rooms and bedrooms
Worth knowing
- No confirmed UK Amazon listing — search using the exact SKU (BHR5101EN) rather than the generic product name to avoid mismatched or grey-import listings
- Price is an approximation and needs a live check before you commit
- At up to 64 dB on maximum, it's the loudest model on this list at full speed
ⓘ As an Amazon Associate, PreparedBritain earns from qualifying purchases. We may earn a commission when you buy, or a fee when you request a quote, through our links. When two products are close, commission can decide which one we pick. A clearly better product always wins. Amazon prices come from Amazon's own product data and show the date and time they were retrieved. Prices at other retailers are checked by us, less often. Prices and stock can change at any time, so always check the retailer's price before you buy.
Who shouldn't buy this
Don't buy it if you want to buy with total price and listing certainty today — the Levoit, Blueair or Philips entries here are more solidly confirmed on price and stock.
This is a Researched review: we haven't used this product. We check every specification against at least two independent sources, re-check the UK price on a schedule where we can track it automatically, and say plainly who it isn't for. Commissions never change a rating.
If this isn’t the one
Best for A large living room or open-plan space where filtering speed and a quiet night setting both matter.
as of 4 Nov 2026, 19:07 GMT · Details
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon.co.uk at the time of purchase will apply to the purchase of this product.
Best for A small-to-medium bedroom or home office on a budget
as of 4 Nov 2026, 19:07 GMT · Details
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon.co.uk at the time of purchase will apply to the purchase of this product.
Best for A small bedroom or home office on the tightest budget
as of 4 Nov 2026, 19:07 GMT · Details
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon.co.uk at the time of purchase will apply to the purchase of this product.Free alerts for your home
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