Not automated but you can get a radon manometer to identify pressure differentials. Install on both sides of the filter. Identify where pressure is with a new filter, mark it, and see how it changes over time and determine when to replace it.
swampdownloader
joined 2 years ago
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I forget the brand but there was one you could etch a design on the cover of the CD with the burner. Futuristic tech at the time.