I've had my upright standing (looks like a vertical tube) air purifier for maybe a month. Recently I'm noticing oddities associated with it.

Tonight I was noticing buzzing at my feet along one wall. Along this same wall in my bedroom and bathrooms. And den. These 3 rooms share one wall.

Maybe a little more than usual today. But, when I turned off the machine the buzzing disappeared. I live in a condo. Don't think it was a neighbour being moronic.

Other days I would sometimes notice a blanket of buzzing on my floor covering my tiny den, extending into the hall and then my tiny kitchen. They are side by side.

Is this normal? Has any one else experienced this with Honeywell HEPA air purifiers?