Is it possible to paint duct or cover it up ? Are you serious,of course it's possible to paint or cover up anything.

I appreciate that very much! Thank you! This might seem like a silly question but does boxing it up cause any issues? Unsure if it needs any air flow. Having a hard time finding any info on Google.

To klem1: Thanks for your reply. Helpful. I obviously didn’t phrase that correctly. I meant would either of those two things cause an issue or is there any important info to know before doing either. I’m clearly not an HVAC professional and came here to get some guidance.

Since it is non rigid I would frame it in and cover it with drywall. I left a rigid duct exposed in one of my closets to save a few inches

Best solution is to place the boot close to the floor if possible. Then place a shelf over the top of it.

You can frame it but the framing will eat away at the space. Preferably, build a 2-sided, closed on one end plywood duct cover. Attach some firing strips to the wall--Use some toggle fasteners to fasten to wall as there likely are no studs to nail into where you will need them. Then a few screws thru the plywood cover and into the firing strips. Prime, caulk & paint.

You could also replace the flexible duct with a right metal type. That is probably less expensive than hiring a carpenter to build a frame around it and cover it with sheetrock. Then you could prime and paint.

A flexible duct is fragile and easily deformed if pressed upon. If the closet becomes stuffed with items as typically happens, there is a possibilty something inadvertently is pushed or falls into it. The duct can get squashed or torn. That is why posters are recommending building a box around it to protect it. I was proposing an alternate suggestion.

If the flexible duct is not a concern, then it can be spray painted if you use the proper primer and paint.

Just build a box around it. Four 2x4s and some drywall. It’s probably this tall to avoid a tile wainscot, one of my bathrooms was done this way though an adjacent closet.