I'm about to begin the process of installing duct work in a new build basement. I've done some in the past and have had a local company lay out the supplies/returns for me on the floor plan. A few questions that I forgot to ask. In the past, I've just used sheet metal screws and foil tape in the collars and any seams. Is it advisable to use mastic instead of tape on the collars? Seems like it would be easier than getting the tape around the circular figure. Screws/tape fine on seams with mastic advised on any of the 0-90 pieces. Last thIng..obviously the bathroom will have an insulated duct going outside from the ceiling. Is it doable to place the register on the ceiling as well? That's where the rest in the basement are going and would be easiest.

I would love some advice about how to control ducted cool air from my Heat Pump Water Heater to adjacent room w/ Nest Thermostat setpoints. I plan on adding two dampers to to supply or exhaust the cool air, depending on interior temps, either one powered and one barometric or two powered. Currently we have a heat only furnace and use the Nest to also control the furnace fan to intermittently ventilate the house per a schedule. I've looked at manual dampers and am interested in a bit more automated control using a the Nest thermostat. Any wisdom would appreciated.