: I have been looking at ideas to make it a little quieter without paying a bunch of money for the kit i saw somewhere. I was skeptical of the kit anyway. I decided that since I don't use the 'dump' vent at all, i would use a method similar to what i saw someone do on another site. Opinion: I don't think the dump vent cools it down any faster, plus in my unit it dumps right next to the thermostat and will probably make it cycle before the rest of the trailer is cold.
I used a bubble foil windshield shade i was no longer using. I carefully cut out a rectangle to snugly fit the dump outlet. I then used that as a template to cut 3 more so i would end up with 4 layers. One layer would have blocked the air leakage but 4 layers helps with sound insulation. I used foil tape to seal the material on all 4 sides. Reinstalled the cover and BAM! Big noise reduction. Oh, it's still loud, but it really takes the edge off. Blower noise is reduced and noise from air leaking thru the closed dump vent are gone.
The donor shade:
The 4 layers tape sealed over the dump vent:
I had seen people mentioning poor tape sealing from the factory but figured that wasn't often an issue. That is until i was looking to remove a speaker from the ceiling to see what better aftermarket speakers would fit. I noticed the speaker i wanted to remove was about 2 feet away from the a/c and was cool to the touch. Seemed weird. When i removed it, there was cold air coming out the opening!
So while i had the cover off for the above enhancement, i inspected the entire inside of the output side of the a/c. Sure enough, there was a gap around where the ducts are connected where tape was missing. It was small, but apparently enough to let a good bit of air into the ceiling. My unit is using 2 duct outlets, 1 feeding the bathroom and bedroom and 1 feeding the living area vents. Both had sloppy taping. There is one more side where an opening is provided for ducting that needs to be taped closed. That was sketchy too. where the pieces of tape overlapped, some were kind of loose. Also the white foam piece that separates the air intake from the air output was absolutely the worst! it was just placed in there and not taped AT ALL. air was blowing straight down on the cover. at the top of the foam piece i could stick 4 fingers through from the output side into the intake side.
I spent about an hour and used about 1/2 roll of metal tape to completely retape and seal everything off and ensure a true wall between intake and output. Before sticking my hands up in there, i taped all the sheet metal edges so there would be no sharp edges to cut me. Also turned off the a/c breaker since my hands would be all up in the wiring. I think you can see the taped edges in the pics.
I can't believe the airflow now!!! I thought it was pretty good already, so i didn't quite know what i was missing. Each and every vent has a very noticeable increase in airflow. One in particular, the kitchen vent, was weak compared to the others in the living area and it now feels as strong as the others. I actually think I'm going to need to pull the cover again and partially tape over the duct entrance feeding the bathroom and bedroom. Those two are like a hurricane blasting in there. I try closing the damper on them and they whistle and a bunch of air still comes.
I had no 'before' pics, but here are 'after'. I just wanted to show how nice and clean it is and fully taped off.
Foam piece between intake and output side:
Foam piece again, other end:
Living area duct
Back wall of intake. Wouldn't affect cold air output, but the opening had tape falling off and you could see the ceiling foam, etc.