I had heat and air ducts put in my train room. I didn't like the way the aluminum foil insulation looked. So since I had some scrap carpeting I decided to cover the ducts with carpet.
Step 1: Boots Around the Vents
I started with cutting some carpet that I could mold around the vent openings. To hold these boots up I punched holes in the carpet and used heavy cord to tie them up. You can't see the top of the duct without a ladder, so coverage there is a bit spotty. No one has ever noticed.
Step 2: The Big Piece
Once the boots were in place I cut a piece to cover the duct. Measure the length of the run and the circumference of the duct and cut a rectangle of carpet. Then measure the gaps for the vents. Again, punch holes for cords to hold the whole mess up.
Step 3: Paint the Carpet to Match the Ceiling
So to really make it blend in I painted everything to match the ceiling. I used an airless sprayer to do this and was amazed how much paint the carpet soaked up before changing color!
It ended looking OK and the aluminum foil insulation is protected from damage.
Hope you find this useful.
Best Wishes, Carl.