Xiaomi Smart Air Purifier 4 review
Buyers who want the highest published CADR for their money and are comfortable double-checking price and stock themselves
By Tom Calder
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.
ⓘ 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 — it never affects what we recommend. 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.
- 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
- 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
Who shouldn't buy this
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.
Key specs
| Room size | 48 m² |
| CADR | 400 m³/h |
| Filter | 3-in-1 filtration, removes 99.97% of 0.3-micron particles |
| Noise (min) | — |
Our rating is a considered spec-and-evidence verdict: we verify 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 a product isn't for. Commissions never change a rating. Read the full methodology →
Alternatives to consider
as of 20 Sep 2026, 12:29 BST · 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.as of 20 Sep 2026, 12:29 BST · 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.Want this cheaper?
We don't yet re-check this product's price automatically. Leave your email and we'll tell you when it drops — nothing else.