On 2020-08-10 3:05 p.m., Cindy Hamilton wrote:
)
>
> Heh. We have a sheet of paper affixed to the furnace plenum by a magnet
> and a pencil hung nearby with a piece of string. At least we know how
> late we were.

If you went by the calls you get from duct cleaning services saying that
it is time to get them done again it would probably be an adequate
reminder for the filter change.