AC tips for prospective owners

[sourdough]

There have been a lot of threads asking about AC's; size, how many etc.

I want to give a brief? synopsis of my experience with this trailer over the last 3 summers.

*If you are close to 30' or more get 2 ACs. No question.
*If you are buying a trailer don't get one with black sides on the slides.
*Go for lighter colors for the ACs and vent covers.
*Get frameless, tinted, DOUBLE paned windows.
*Get 50 amp service ( for the 2 ACs )
*Have a couple of fans to circulate air
*IMO get a non ducted AC (ours is 13.5) for the bedroom for those days that are just "out of bounds" so your bedroom can stay cool. (I've not had a dual zone AC so don't know if those would accomplish the same thing).

We had 2 ACs (15k and 13.5k) installed on our new trailer. I've never had a situation where I couldn't run both until today; we just came in from FL 3 days ago; it was 105 today and is 101 at 7:30pm. I can only run the 15k on our property next door since I have 20 amp service. It is about 90 degrees inside and the AC is running constantly. Checked the output from the AC at the vent and it's 60-61 degrees; seems too hot to me (our house is 51*).

Anyway, the installation of a 2nd AC seems a no brainer to me on any trailer of any size. On the other hand, my furnace (trailer) is either a 35k or 40k btu. Maybe I can find an AC of similar size?? OR, I have 2 5 ton
ACs at the house; maybe they make one about the size for an RV??

Prospective owners need to know that the things I mentioned above can help/hurt your ability to keep cool in extreme temps. Just for thought.

[GaryWT]

The key here is extreme temps. Being from New England and having one 13.5 in my 35 foot trailer, I have not had a problem staying cool. Usually have is at 66-70 degrees. If I was down south, I am sure I would need more.

[Tbos]

Well said. A couple of fans would have made the last 10 days a little better. My 13.5AC has done a good job but it has been working hard. Some additional shade would have been helpful too.

[Mike484]

We have one 15k BTU in our 2890rl and we were comfortable all weekend. There were heat advisories out but the A/C did not run continuous. I questioned having only one unit here in Texas, but so far (knock on wood) it has kept or rig cool.

[sourdough]

Originally Posted by Mike484

We have one 15k BTU in our 2890rl and we were comfortable all weekend. There were heat advisories out but the A/C did not run continuous. I questioned having only one unit here in Texas, but so far (knock on wood) it has kept or rig cool.

Out of curiosity, have you ever read the temp of your AC outlets with an infrared temp gun? If not, can you? I would be interested to know what your output temps are.

[therink]

I have one 15k on my 37 foot fifth wheel and have never had a problem keepimg cool inside however I rarely park in full sun. That makes the biggest difference in my opinion
Another thing is do not trust the craftsmanship of the factory when they build these things that all duct work and plenum is sealed properly to provide max efficiency. The first thing iI did in the last 3 new trailers I have owned is seal up all air loss areas with foil tape (in ceiling behind vent openings, and plenum area). Also found messy foil tape job by factory which can restrict or alter air flow.
One last thing I did was close off the unused portions of in ceiling duct work beyond the foremost and aftmost duct openings. This creates much better aerodynamic flow out these duct openings.
Finally, campground voltage below 110 volts will hamper the ACs ability to work aand will cause it to overheat. Ultimately will damage it. This is very common. I solved this problem by keeping close eye on voltage with meter and I installed an in line Hughes Autoformer which regulates and boosts voltage by up to 10 percent. It was expensive but worth it. No more waiting for toast in the morning.

[ctbruce]

101 when we parked yesterday and no shade. Turned on both air conditioners, front on dump and rear garage on vent. Turned on the vent fans to pull the hot air out for awhile and set 2 small fans to circulate. And went to dinner. Cooled off nicely! Circulation is your friend!

Sent from my SAMSUNG-SM-N910A using Tapatalk

[sourdough]

Originally Posted by ctbruce

101 when we parked yesterday and no shade. Turned on both air conditioners, front on dump and rear garage on vent. Turned on the vent fans to pull the hot air out for awhile and set 2 small fans to circulate. And went to dinner. Cooled off nicely! Circulation is your friend!

Sent from my SAMSUNG-SM-N910A using Tapatalk

This is what we normally do and have never had a problem either. Having just returned from FL we have the RV parked in our property next door in direct sun at 107 degrees (yesterday). Just by checking things over the 2 months we were in FL (we had no problems there in direct sun) and the 5 days we've been back here, the items I listed seem to contribute to a considerable amount of heat accumulation inside.

When we bought the trailer we liked the color scheme and the black paint on all the slide sides didn't register. All the roof ACs and vent covers are black as well. Next time I'm going with white or a lighter color at least.

[gearhead]

The lighter colors may be a trend, again? When we did the Montana HC factory tour in June I noticed all the HC trailers were beige. Works for me better than black.
Just me but summer here is hibernation time. I'll fish here, but will be home by 11am. I have to drive 16 hours to get out of this heat. Sitting around a campground in 95F and high humidity don't do it for me. But about mid September....

[jameswbarton]

I bought a 2016 Montana High Country 375 FL with two AC units one 15,000 btu and the other 13,500 btu. I did not purchase dual pane windows and slide covers as they become maintenance issues if you keep a coach for many years.

One would have thought that having 2.25 Tons of AC would be adequate on a RV of 375 sq feet but they could not cool the coach lower than 8 degrees from outside air temp in full sun in Michigan. So my tips are:

1. Get a white roof coating. Mine is beige and kept the roof hotter on the main and slide roofs.

2. All white coaches are better. My slideouts that have black walls are much hotter that the lighter beige walls.

3. I should have gotten double pane as the single panes are cheap and not very good windows.

4. Make sure your AC units are installed properly. Mine were not installed per Dometic specifications and I had to do several things to get the proper airflow out of the ceiling ducted system. My ceiiing vents were not proper air flow nor properly installed. I had to install three more vents and fix the poor vent installations as they used vents with too long a collar blocking airflow.

5. Install floor heat vents that have shutoffs to keep cold air from going into the furnace supply air system. My Furnace drew air from the basement causing hot outside air into the coach. When the furnace was not on, it let cold air from the interior into the basement trying to cool the outside air.

6. I have now sealed and isolated the basement from the interior of the coach for both heating and cooling. If you do this you will have to find another way to heat the basement to keep the pipes from freezing. I do this using a Marine Quality Bilge heater that has adjustable heat ranges and freeze functions.

Air intrusion is the biggest issue on my Montana The basement is not really insulated nor air sealed and will take a considerable amount of labor and material to insulate and seal. The non insulated 4 inch heat flexible ducting should be replaced with insulated 4 inch ducting. This would not be needed unless you intend to be in winter cold or desert heat.

My Montana High Country was advertised as being 4 season liveable and ideal for full timing, and further stated it passed testing for cold. The factory rep reminded me this was a chamber test without wind and snow.

With my repairs so far I have increased the cooling from 8 degrees to 30 degrees in full sun. It has made heating the coach far faster with much warmer air. It is no longer drafty due to air intrusion from the basement.