Sejoy KF-3500A 4L Humidifier Review: Can It Handle a Large Room in 2026?
The Sejoy 4L humidifier delivers reliable cool mist with smart humidity sensing and easy top-fill design, but lacks WiFi, timer, and aromatherapy features.
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Best For
How this humidifier scores for different use cases
The Sejoy offers quiet ultrasonic operation, 7-color nightlight, and smart constant humidity control. The 4L tank provides around 12 hours of runtime, which covers most nights but may not last a full 8+ hours on high settings.
Cool mist only and auto shut-off provide safety basics. However, no BPA-free certification is listed, and the lack of a dedicated sleep mode or timer limits nursery-specific functionality.
The 4L tank is decent but no coverage area is specified, suggesting it may struggle in truly large spaces. Without a stated mist output rate, large room performance is uncertain.
At nearly 10x10x15 inches and 5.89 pounds, this humidifier is too large and heavy for most desktops. It lacks USB power and is designed for floor or table placement in living spaces.
No WiFi, no app control, no voice assistant integration. The built-in humidistat and LED display offer local smart features only, with no connected home capabilities.
At 5.89 pounds with a 4L tank and standard power plug, this unit is not portable or travel-friendly. It requires a wall outlet and is too bulky for luggage.
Our Verdict
The Sejoy KF-3500A gives you a solid 4L cool mist humidifier with smart humidity sensing. Its built-in humidistat tracks your room's moisture level every second.
You fill the tank from the top. No flipping or spilling. Three mist speeds let you adjust output to match your room.
The 7-color nightlight adds a nice touch for bedrooms. You can run it as a standalone light even when the humidifier is off.
Safety features include auto shut-off when water runs low. A buzzer and flashing screen alert you to refill.
This humidifier skips smart home features entirely. No WiFi, no app, no voice control. You also lose aromatherapy and warm mist options.
The 4L tank runs for about 12 hours. That covers a full night on lower settings. You may need to refill on high mist.
This unit works best in medium bedrooms or living spaces. It fits buyers who want simple, reliable humidity control without connected features.
What We Like
- 4L tank gives you up to 12 hours of mist without refilling
- Built-in humidity sensor tracks room moisture and shows it on the LED screen
- Top-fill design makes adding water quick and mess-free
- 7-color nightlight works on its own as a standalone light
- 3-speed mist control lets you pick low, medium, or high output
What Could Be Better
- No timer function to schedule automatic shut-off
- No aromatherapy tray for essential oils
- No warm mist or dual mist option for cold and flu season
- No WiFi, app, or voice control for smart home setups
- No dedicated sleep mode to dim lights and lower mist automatically
Standout Features
Full Specifications
Physical & Dimensions
| Weight | 5.89 |
| Width | 9.84 |
| Depth | 9.84 |
| Height | 14.96 |
Features
Included Features
Not Included
Frequently Asked Questions
Common questions aboutSejoy Humidifiers for Bedroom, 4L Top Fill Ultrasonic Humidifier for Large Room, Cool Mist Plants Humidifiers with Nightlight, 12H
How long does the Sejoy humidifier run on a full tank?
The 4L tank provides up to 12 hours of continuous mist. Runtime depends on which of the 3 speed settings you choose. Lower speeds make the water last longer.
Can I use essential oils in this humidifier?
No. This humidifier does not have an aromatherapy tray or essential oil compartment. Adding oils directly to the tank can damage the ultrasonic element.
What happens when the water runs out?
The humidifier beeps 5 times and the digital screen starts flashing. It automatically stops misting to prevent damage. You then refill through the top opening.
How do I set the target humidity level?
Use the touch controls to set your target between 45% and 80% RH. The sensor checks room humidity every second and adjusts mist output to maintain your chosen level.
Is this humidifier quiet enough for a bedroom?
The ultrasonic technology produces very fine mist at low noise levels. The manufacturer describes it as quieter than a whisper. No specific decibel rating is provided.
Best For
How this humidifier scores for different use cases
The Sejoy offers quiet ultrasonic operation, 7-color nightlight, and smart constant humidity control. The 4L tank provides around 12 hours of runtime, which covers most nights but may not last a full 8+ hours on high settings.
Cool mist only and auto shut-off provide safety basics. However, no BPA-free certification is listed, and the lack of a dedicated sleep mode or timer limits nursery-specific functionality.
The 4L tank is decent but no coverage area is specified, suggesting it may struggle in truly large spaces. Without a stated mist output rate, large room performance is uncertain.
At nearly 10x10x15 inches and 5.89 pounds, this humidifier is too large and heavy for most desktops. It lacks USB power and is designed for floor or table placement in living spaces.
No WiFi, no app control, no voice assistant integration. The built-in humidistat and LED display offer local smart features only, with no connected home capabilities.
At 5.89 pounds with a 4L tank and standard power plug, this unit is not portable or travel-friendly. It requires a wall outlet and is too bulky for luggage.
Scores
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