[Shop-talk] Furnace Filters

[Brian Kemp]

If you have 1" filters, do a search for "air filter whistle".  It is a 
simple two piece plastic device you put in the filter that whistles when 
the filter needs to be changed.  Got mine in a kit from the local 
utility company.

Here is a description:
https://yourfilterconnection.com/blogs/help/what-is-a-furnace-filter-whistle

Caution - If you have a newer HVAC system still under warranty, you may 
be required to use the specified filter for the warranty to be valid.  
My installer made sure to point this out.  My Lennox MERV 16 filters run 
$70 each in a two pack, but last 9 months with two shedding cats.

Brian