Comment by emag

I just let my thermostat alert me, based on run time. It worked with my old programmable, it works with my Nest (yeah, I know). And since I buy 3-packs of the filters, when I get down to the last one, I just add "16x20x1 filters" to my shopping list. When I'm at Wallyworld or Home Despot/Blowes, I'm there for a reason, open my shopping list, and see the filters listed...