What is best way to seal gaps into space above ceiling? (roof, paint)

[PNWGuy]

I'm trying to make my house more energy efficient by getting all the low hanging fruit - sealed air handler cabinets, added missing weather stripping to entry doors, use CFLs/LEDs where possible, etc.

Now I need to seal the gaps where the venting from the range hood goes into the ceiling, as well as the supply? Of the air handler goes into the ceiling. In both cases, the is about an inch gap all the way around the ducting going into the ceiling, which either let's in warm/cold air, or even insects/rodents.

Wondering if a standard roll of foil tape is good enough for this? Or do I need fiberglass foil tape? I have flat roof above both of these, so no attic access available, any fix has to be done from inside.

[plmokn]

I think there is a tape you would apply and then spray some texture stuff on it then paint over it.

Youtube is a great resource for these types of home repairs too.