Hi,
I'm a homeowner that installed one of your units on a HVAC unit with heating and cooling, it must be about 7 years ago...or whenever it was that oil was about 60-80 cents a gallon. I've never had a problem with your Fan Handler (other than sorting out the original wiring details and finding a good place to mount it), and I rave about it every year, in amazement about how comfortable our home is...and why it is! A quality thermostat (in my case, a Honeywell electronic with fuzzy logic) teamed up with your fan controller is a great combo. I really appreciate the quiet ramp-up and ramp-down of the fan speeds in accordance with plenum temps. As a building official in CT, years ago I saw a lot of low-end single speed (and possibly oversized) mobile home hot air furnaces installed in closets adjacent to living areas... with cheap thermostats, resulting in temp overshoots and a lot of fan noise, and felt sorry for the occupants. Sorry that they didn't have your system installed.
Thanks for all the comfort I've enjoyed... all these years!
Don Berg
Willington CT.