Red Devil 0841DS RD-DS 181 Acrylic Latex Duct Sealant, 1/2 Gallon, Gray

Air leaking from your HVAC ducts can results in up to a 20% (or more) loss of efficiency. This is because many vents are not properly sealed. Often the ducts are sealed with a poor-quality tape which can result in loss of heated or cooled air. Over time, the duct tape can detach from the ducts, results in air leaks. Even worse is the poor or shoddy workmanship that fails to properly seal the ducts.Our A/C unit was not cooling as efficiently, so I conducted a visual inspection of the ducts in our attic. I found multiple areas where the ducts were not properly sealed.I first applied a high-quality HVAC aluminum tape to all the poorly sealed joints.Then I brushed on the Red Devil Acrylic Latex Duct Sealant. I used a 3” paint brush and it took about 45 minutes to totally paint the sealant over all the taped joints.The latex duct sealant is like a heavy paste and goes on very easily. Even though you could wash out the brush, I used an inexpensive brush and tossed it when I was finished.I was very pleased with how easy it was to apply the latex duct sealant. I was even more pleased with the way it sealed up a large number of small leaks. It dries/sets it about an hour. Very effective seal.This is probably one of the best investments you can make to improve the cooling/heating efficiency of your HVAC system. The monthly savings more than pays for itself.

Perfect consistency. Thick so it won’t drip or run, but applies smoothly and adheres to pretty much anything. I prefer this over the F-Seal which has fibers in it, making it a little harder to apply. Perhaps those fibers makes the F-Seal stronger or better for large gaps, but I prefer the smooth application of this one.One tip, I wipe everything down with rubbing alcohol before applying tape or mastic. This way I remove any dirt or oils and I’m guaranteed a strong adhesion.

This is mastic duct sealant, works as it should. I used this to seal the ducts and seams on my new attic AC installed. PSA: if you get this on your clothes, it will not come out. If you get this on your skin, it will wear off after a day or so. It works very well and is thick. Turns a dark gray when dry.

Very good product, and I love it, I'll see how long it lasts, work perfect

Very slow to set up if you don’t thin out the brush strokes.

Product arrived on time and container was intact and no damage to container. This was a concern from reading other reviews. No issues with this.Got an old paintbrush and went up into the attic to apply this duct sealant. The day before I inspected and re-taped as needed old repair work. I took some damp rags and cleaned the areas I was going to seal. I wanted to be sure the application areas were clean and dry per instructions.I applied the sealant onto my repairs with the duct tape, covering the areas completely with a 2 inch spread beyond the tape job just to be sure the sealing was good. The product was easy to apply with the paintbrush, and coats the areas well. The consistency of the sealant is like a thick pancake batter. I wore a mask because the odor is pretty strong, and wore latex gloves too.The next day I went to inspect and the ducting looks great. The sealant changes color slightly and it blends very well with the gray flex duct. I went ahead and applied to some spots that may need more coverage, and I did that with the putty knife.I’m glad my HVAC guy told me about this product. I had no idea it existed, but he said the duct tape alone won’t pass a property inspection but with the duct sealant it will. Really did a fantastic job and looks like it will last a long time and prevent future leaks where repairs were made. Good stuff!!

Awesome... it does just what it's supposed to do... go figure... ha

Easy to use as long as you have a paint knife. Set and drief within 2 hours so relatively quickly. Great value for money