Is a HEPA H13 filter good for allergies?

Yes. H13 is a high-grade HEPA class that captures a very high share of fine particles such as pollen, dust and pet dander. It helps most with airborne allergens, less with odors and gases unless a carbon layer is added.

Will it really cover 1,400 sq ft?

Coverage ratings assume open space and a high fan speed. In a closed, furnished room expect effective cleaning over a smaller area, and expect more noise when running at maximum.

Does it have an auto mode or air-quality sensor?

No. The listed features are purification and a timer, so fan speed is set manually. If you want the unit to react to smoke or dust on its own, a sensor-equipped model is a better fit.

How often do I need to replace the filter?

Most HEPA filters last six to twelve months in normal use, sooner in smoky or pet-heavy homes. Check the filter every few months and replace it when it darkens or airflow drops.

Expect quiet operation on low and noticeable fan noise on high. Large-room purifiers move a lot of air, so the top speed is best used when the room is empty or during cleaning sessions.