We also discussed / negotiated with Blitzortung in mind, and will also use a single speed... however the speed will be set up for 'best' flow, at install using a controller... that's "standard' for these units... so we'll see if any 'leak' reflects through mains, or.... whatever. We'll begin 'eval' on that during install... and see if any 'mediation' or mod needed during the process, if possible.... especially since all new electrical will be connected. That blower motor control would probably the source of any 'noise' if any is produced.
The outside unit will install roughly where present is, which is about 30 feet diagonal below the E field probes... a
The company is operated by a long time friend, and we laughed a bit at all these folks installing the electric utility 'demand conservation' electric control boxes... two/three of which cause me intermittent interference in the neighborhood... he said when they do an install and those are in place they remove them and "tell the owner to call the utility come pick them up"... since they want to control the HVAC at the times the owner would be desiring the HVAC to operate! And with the lower demand with newer systems they were just a PITA for the owner's comfort... (I'd already, couple of years ago, told my utility to quit nagging me about installing one.) ... now if I could just get rid of a handful of so-called 'smart meters' in the neighborhood that folks have allowed to be installed.... arrrggh...
Yep, HVAC blowers make GREAT shop or even home filter drives... I did that yeas ago in the basement of an older home where I did a lot of wood work... using the motor from a furnace... still have the blower assy somewhere up in the attic... even used an HVAC filter with it to trap the dust... wash and replace...