Which humidifier pad does the Aprilaire 550a take?

Aprilaire 550a humidifier humidifier pad

Aprilaire 550a: the humidifier pad is part 10. Source: Aprilaire, checked November 6, 2026.

Wicks harden with minerals and soak up less water over time.

1Humidifier pad10

Part numbers come from Aprilaire (source), checked November 6, 2026. Amazon buttons open a search for the part number; we may earn a commission.

On a label on the base, often under the water tank.