On Tuesday, September 19, 2017 at 8:37:46 AM UTC-4, TimR wrote:
On Sunday, September 10, 2017 at 9:44:45 PM UTC-4, trader_4 wrote:
Like I said, I've yet to see
a system using air pressure or temp measurements to gauge filters
in a residential application.

https://www.amazon.com/Simply-Conser.../dp/B009T7TJWA

Like I said, I have yet to see one of those in use on a system.
Have you?