One more question. believe this to be true. Friend told me the coil would sweat conciderably in the summer if it is after the acoil. So then I have two choices right. Place it after acoil adjust duct accordingly for oversized HE. And then remove In summer time> Second option install HE in return trunk adjust ducting accordingly and filter. Thirdly put the furnace horizontal lots of work, suck refrigerant back to compressor break the refrigerant lines, allthread unit into position, nitrogen, vacuum down. put the HE just before Acoil. Redo duct work. Really thinking the first two options will be best. Havnt even thought about the fan speed yet. probably could hook up a fossile fuel kit to act as the switch, Or just a HoneyWell 8000. I still like the idea of the blower not turning on untill the heat is in the coil too.