RV A/C ceiling vent changes -- could use some tips

Wanted to give the results of my efforts this past weekend. Short version...huge success balancing out the air flow/temps in the camper...and much increased airflow to the bunkhouse where it was needed most.

I replaced all of the fixed-louvered vents with adjustable-louvered vents. Almost all of the holes that were drilled into the ceiling and through the vent ducts were taped up very sloppily. For each vent, I examined the seals and either removed the old tape/foil and re-sealed it...or just taped the areas that had gaps. I closed off 90% of the air in the two bathrooms and the master bedroom to force more air into the rest of the coach and especially the bunkhouse. Those yielded pretty good results. I also took down the ducted A/C's return cover and examined the inside. Low and behold -- a hole about the size of a silver half-dollar between the plenum and one of the ducts that was taped improperly. I taped up that hole -- which was right below the blower cage -- buttoned it all back up -- and checked out the airflow to the vents. All of them increased with that repair. The real test was yesterday. It was full sun and 92 degrees at my house. I ran just the main A/C unit (left our bedroom unit off), set it to 73, and left for a few hours. Came back around 2:00 and the living room was 73 degrees. When I opened the bunkhouse and took the temperature there, it was also 73 degrees. SUCCESS!! Well worth the few hours of research and few hours of repair time. Plus I have balanced the air flow and now nobody will freeze their arse off in the bathroom while taking a shower. The bathrooms were the coldest since they had a dedicated vent in each small space. With them mostly closed off they now stay cool without getting overly cold. Best of all is that my girls will sleep in cool comfortable A/C at night and have the same temps in the bunkhouse as the rest of the camper. Not sure what percentage of A/C was going into the attic space, but I like that I have taken all of that back and put it into the living space where it belongs.

We are fulltimers in a 38' Montana 5th wheel and I discovered that we were air conditioning our basement storage area because of the furnace return grills on 2 of our steps up to bath/bedroom area. Now each spring after we are finished with the furnace for the season, I pull the grill covers and place a piece of luan plywood behind each one. Now all the cool air stays where it should be and the a/c's each run less. I stained the luan to match and you can't tell they're back there. Just be sure to remove them when furnace is needed again in the winter.

Partner, a small spot cooler might be your best bet, for now.

I had one RV that had exceptionally poor airflow and I found 6" round stepdown diffusers and that did the trick. The stepdowns have more free area/less restriction and farther throw. I do the same thing in offices, or wherever, when airflow/distribution is a problem. Flat bottom diffusers are the most common and most of them are junk but I see stepdown diffusers in well designed buildings that didn't have such a tight budget. You can put a balancing damper or shut-off damper above the diffuser but they are usually too thick for an RV. I used to be able to buy pull-chain dampers for the top of the diffusers and people could play with them at will. They fixed 90% of the seasonal air volume problems in offices. Craig

manley wrote:
You may also want to check the plenum - where the a/c goes into the ductwork. That made a HUGE difference in mine, as did adding vents with the shutoff. I added 3 vents - 2 in the living room, 1 in the bedroom. All of the vents are now similar to the "Jetstream" shown in the link above. They rotate, adjust, and cut off completely.

This is now on my list for the weekend - once I figure out how to get in there. :)

Leonandlisa wrote:
You got me looking at mine since I would like to get vents that close so I can force more air to the vents I want. When I pulled off the vent cover I noticed that the extension that attaches to the duck work was taped but very poorly, I used some aluminum tape and fixed all the vents and maybe it is just in my head, but it seams that they all blow better still. I still need to find vents that fit my trailer but this has helped I think, just thought you may want to check yours too.

Leon

The one I pulled down was not taped at all so guess I'll be examining them all closely. Thanks for th tip.

You may also want to check the plenum - where the a/c goes into the ductwork. That made a HUGE difference in mine, as did adding vents with the shutoff. I added 3 vents - 2 in the living room, 1 in the bedroom. All of the vents are now similar to the "Jetstream" shown in the link above. They rotate, adjust, and cut off completely.

You got me looking at mine since I would like to get vents that close so I can force more air to the vents I want. When I pulled off the vent cover I noticed that the extension that attaches to the duck work was taped but very poorly, I used some aluminum tape and fixed all the vents and maybe it is just in my head, but it seams that they all blow better still. I still need to find vents that fit my trailer but this has helped I think, just thought you may want to check yours too.

Leon

Okay...finally figured out most of what I needed. With much research, I eventually figured out that the vents I have in my camper are D&W 8950s. The vents are held in place by 4 little tabs that can be disengaged pretty easily with a little tug on the louvers. I removed a vent and then removed the extension it snaps into to take some measurements. The cutouts holes are 5 7/8" and the extensions are less than an inch high.

D&W also makes adjustable louvered vents called the Jetstream 8850.. The transition will be as simple as pulling down the old vent insert and pushing in the new one since they share an extension. I have 7 vents in my camper -- and at $6.00 per replacement, I'll just do them all.

I'll do some testing the weekend after these come in to determine if closing off a few vents increases airflow in the bunkhouse to where I want it.

This thread is a step in the right direction for helping me understand what's up inside the ceiling: clicky