AC and floor vents

[vmcvey]

I’ve seen many places online where people say to cover floor registers and the vents under the stair to stop the hot air rising up. We are having a heck of a time keeping our temperature under 84 degrees down here in south Florida. It’s bad enough we just bought this RV (2020 Montana High Country 381th) brand new and found the front ac only works as a fan. Is it okay to block off the air from underneath?

[Frank G]

I’ve seen many places online where people say to cover floor registers and the vents under the stair to stop the hot air rising up. We are having a heck of a time keeping our temperature under 84 degrees down here in south Florida. It’s bad enough we just bought this RV (2020 Montana High Country 381th) brand new and found the front ac only works as a fan. Is it okay to block off the air from underneath?

You can block it off when cooling, and it makes sense. It needs to be open when heating, it is the return air duct.

[vmcvey]

My daughter said that when she tried it (very humid area like me) that condensation developed in the registers. Is that a problem? Does it cause problem with the under storage or ventilation?

[travelin texans]

I seriously doubt that blocking off those couple small spots will improve the cooling of a poorly insulated box enough that you could ever tell any difference. You'd be better off searching/performing all the acs mods listed throughout this forum before worrying about those little areas.
If you're parked & need the front ac working contact you're dealer to get approved for a mobile tech to come to you under warranty.

[vmcvey]

Heat literally pours from the registers. It’s insane how we avoid areas with them.

[wiredgeorge]

You might want to look into getting the front A/C fixed. You might also want to search threads here on this forum for ways to improve the efficiency of what you have. There are a lot of pretty fair tips on maximizing the efficiency of air conditioner systems as many of the tips are fixes for things that weren't done quite right at the factory. I have tinted my windows real dark, sealed the opening between vents inside the ceiling and the void where cold air escapes, sealed the inside of my lower A/C unit so cold air doesn't mix with the return, put styrafoam in the voids beyond the ends of the duct runs so again I am not cooling the void above the ceiling and clean my A/C filters. Lots of discussion that can be searched.

[vmcvey]

We are set to take it in already but the appointment is a way out. Trying to stay cool in the meantime.

[wiredgeorge]

That ain't gonna happen in a large camper with no A/C in the main cabin. I would consider calling the dealer where you have an appointment and seeing if a local RV repair person could do a fix/swap, etc. and have it covered under warranty. Since I don't buy new trailers with warranties, I am not an expert and perhaps one of the folks who know something about this could chime in. I do think the A/C is probably Dometic but may be another brand these days like Coleman or Furrion but may be covered by a separate warranty outlined in one of those zillion pamphlets you received when you bought the thing.

[Frank G]

For those not familiar with the way Keystone fifth wheel units are made the steps leading to the upper level, normally the bedroom and bath, have slotted fronts. These fronts are open to the utility spaces under the bathroom. The utility spaces house the water heater, furnace, converter, water pump and a assortment of plumbing, heating and electrical lines. Conditioned air will seek these lower spaces through the open front steps. The smaller floor registers are connected to a common housing with ducts leading to the bottom most level, Holding tank spaces. Again an outlet for conditioned air. These losses may not be significate but when every BTU of cooling counts, your choice.

[Msmith2054]

If hot/warm air pours out from them, Lowes or Home Depot have flexible magnetic covers for a/c registers. Self stick, easy to remove. Designed to be temporary, the magnetic material gives a good seal all around the outside edge. But get that front A/C fixed also.