'When I pull my hand across the outside of our newly installed air
handler my hand comes back wet. This is true on most of the upper
surfaces of the unit. The installer says this is normal. I'm 70 years
old and have had a lot of Air Conditioners both old and newly installed
and I don't ever remember the outside of the AHU being wet.
Is this normal? '
REPLY: It is frequent if thats what you mean by 'normal' . The surface
of the airhandler/supply plenum has reached the dew point of the air
which is why you have condensation on the outside of it. You need to
apply some half inch insulation such as fiber board to the outsides.
'Would it be ok to use that "foil" ducting tape to stop this air from
coming out from these joints?
REPLY: Yes, but apply it when the surface is dry and at room
temperature. Make sure its not duct tape because it will dry and crack
then fall off in time. Use aluminum tape sold at Menards or Home Depot.