Listen up =>
If you have computers (&heat); you have AC and that is $.
A dirty AC filter costs $ & of course dust in your computer, etc.
Check out FilterWatch on Kickstarter.
I believe they have added a ThingModule - the only product I have heard about so far.
Here we go!, let’s fund this one because - you really can not afford not to - probably will pay for itself in 3 months.