Glow covers about 1,000 sq feet. Generally, we recommend one unit per closed wall environment (i.e. one for the nursery, another for the bathroom, etc.) Glow is ideal for any average sized room, especially a bedroom or nursery. We would recommend putting a Glow in every room for the most accurate tracking of your air.
Glow should be placed directly in the wall power outlet. It should not be plugged into to a surge protector or an extension card. We recommend that Glow be near standard standing level (48 inches or 122cm) for more accurate readings.