Quick Take
The Levoit Core 400S is the smart evolution of the budget-friendly Core 300, adding meaningful upgrades without premium pricing. The laser dust sensor drives an auto mode that genuinely responds to air quality changes, and WiFi integration lets you monitor and control from anywhere.
Overall Score: 8.7/10 - Best Smart Mid-Range
Safety Analysis - Score: 8.8/10
H13 True HEPA Filtration
Medical-grade H13 HEPA captures 99.97% of particles at 0.3 microns. This is genuine filtration, not HEPA-style marketing.
Zero Ozone
No ionizer in the Core 400S means zero ozone production. CARB certified for California sale.
AirSight Plus Technology
The laser particle sensor provides real-time PM2.5 readings displayed on the unit and in the app. This is not a gimmick; it accurately reflects air quality changes from cooking, opening windows, or pet activity.
Performance - Score: 8.5/10
CADR Ratings (AHAM Verified)
- Smoke: 260 CFM
- Dust: 256 CFM
- Pollen: 260 CFM
Solid mid-range performance that outpaces the Core 300 by about 80%.
Coverage: 403 Square Feet
Suitable for medium bedrooms, living rooms, or open-plan spaces. For optimal 4-5 ACH, use in rooms up to 200 sq ft.
Smart Auto Mode
The auto mode responds within 30-60 seconds to air quality changes. I tested it by lighting a candle and opening windows during pollen season; it ramped up appropriately both times.
Value - Score: 8.8/10
At $220, the Core 400S delivers smart features typically found in $300+ units. The 2-year warranty and $40 annual filter cost make long-term ownership reasonable.
The Bottom Line
The Levoit Core 400S is my go-to recommendation for families wanting smart features without premium pricing. The laser sensor, auto mode, and WiFi control are genuinely useful, and the H13 HEPA delivers real filtration.
Final Score: 8.7/10
