Blueair Blue Signature Large (SP4i) vs Dyson HushJet Purifier Compact HJ10
Blueair Blue Signature Large (SP4i)
Dyson HushJet Purifier Compact HJ10
The short answer
Blueair Blue Signature Large (SP4i) comes out ahead overall with 7.8/10 against 7.2/10 for the Dyson HushJet Purifier Compact HJ10. Blueair Blue Signature Large (SP4i) is stronger on noise at sleep-usable speeds and cleaning performance for bedroom size. Dyson HushJet Purifier Compact HJ10 is stronger on indoor-air safety & materials and running cost & ownership. At current verified prices, the Dyson HushJet Purifier Compact HJ10 costs about $140.00 less.
- Choose the Blueair Blue Signature Large (SP4i) if: Light sleepers with a large primary bedroom who will pay for the most quiet airflow and accept an always-on ionizer.
- Choose the Dyson HushJet Purifier Compact HJ10 if: Small-bedroom owners who never want to buy filters.
Scores by criterion
| Criterion | Blueair Blue Signature Large (SP4i) | Dyson HushJet Purifier Compact HJ10 |
|---|---|---|
| Noise at sleep-usable speeds | 9.3HouseFresh: 229 cfm at 40 dB, 34.8 dB in sleep mode. | 7.8Tom's Guide: 24 dB in sleep mode, at modest airflow. |
| Cleaning performance for bedroom size | 9.0455 smoke CADR rated; 229 cfm measured at a quiet 40 dB. | 5.5203 sq ft, no AHAM CADR. |
| Sleep-friendly features | 8.3Night mode, laser PM2.5 sensor, app. | 8.3Sleep mode, app. |
| Indoor-air safety & materials | 5.0Ionizer cannot be switched off (HouseFresh). | 7.2No ionizer stated; electrostatic filter. |
| Running cost & ownership | 5.5About $180 a year in filters (HouseFresh). | 9.05-year filter. |
| Value | 5.8$439.99 on Amazon. | 5.8$299.99 for small-room coverage. |
Specifications
| Spec | Blueair Blue Signature Large (SP4i) | Dyson HushJet Purifier Compact HJ10 |
|---|---|---|
| Lowest-speed noise (manufacturer) | 23 dB | 24 dB |
| Top-speed noise (manufacturer) | 55 dB | — |
| Lowest-speed noise (independent measurement) | 34.8 dBA | 24 dBA |
| CADR (smoke where given, else headline) | 455 cfm | — |
| Recommended room size (4.8–5 ACH / AHAM) | 705 sq ft | 203 sq ft |
| Sleep / night mode | Yes | Yes |
| App control | Yes | Yes |
| Ionizer / electrostatic stage | Ionizer that cannot be disabled (per HouseFresh) | Electrostatic filter (no ionizer stated) |
| Filter type | 7-stage filter incl. pelleted carbon | Sealed 360° electrostatic filter + activated carbon |
| Main filter life | — | 60 months |
Blueair Blue Signature Large (SP4i)
Pros
- 34.8 dB in sleep mode
- About 229 cfm at 40 dB
- Large coverage
- App control and PM2.5 sensor
- Doubles as a side table
Cons
- Ionizer cannot be turned off
- Premium price
- About $180 a year in filters
- Tabletop surface scratches easily
The quietest high-airflow option for a big room, but only for buyers who accept the always-on ionizer and the cost.
Full Blueair Blue Signature Large (SP4i) review →Dyson HushJet Purifier Compact HJ10
Pros
- 24 dB in Sleep mode per Tom's Guide
- Filter rated for 5 years
- App control
- Low running cost
Cons
- Only 203 sq ft coverage
- No published CADR
- Loud at top speed, 60 dB
- Expensive for its coverage
- Bulky for a nightstand per TechRadar
A niche pick for small-room sleepers who value silence and low upkeep over airflow.
Full Dyson HushJet Purifier Compact HJ10 review →Both products are part of our guide The Best Quiet Air Purifiers for Bedrooms of 2026, where you can see every pick, how we score and current prices from each retailer.