AC Unit Efficiency

I'm guessing the btu rating on these POS rv ACs is the gross rating. They have such small coils and fans and low cfm/ton, the evap DT is high and they do little for the sensible load. They need to be at higher cfm/ton range, like 450, so they would do more sensible cooling but that's not going to happen, as poorly as they are designed. I wish I would have borrowed a flow hood from work and check the cfm before I retired. The eer of old split systems in homes was bad and rtus were even worse but everything has gotten better except for rv ACs. I've installed several brands of mini splits and they cool great but not a one of them had an air filter that was worth a ****. The evaporator coils plug up quickly, in commercial service, and they are hard to clean. A mini split with a cassette evap and good air filter would be great in an rv and get the cond unit of the roof. Craig

The best way to improve RV cooling is to find some shade, which is easier to do in the south east versus south west. :-)

The real solution for efficiency is to move to a mini-split system.
Take a long time to pay for it in saved gasoline.

Dividing BTU's by watts has some minor issues.

When it is not impossibly hot outside, my roof air draws as little as 960 watts (13500 btu Dometic). However when it is HOT outside it draws over 1800 watts. These are real life measurements.

So seer is a "moveable feast".

If you want truly efficient and much quieter cooling get a mini-split, probably a double one.

Installation would not be trivial, to say the least, but if you can figure out a way to manage it many of the newer mini-split systems have excellent efficiency.

QUICKSILVER

LG WINDOW UNIT (3) 5,000 BTUs

Just kicks the snot out of one 15,000 BTU roof unit.

It froze me out at temperatures close to 100F and high humidity. The amount of condensation was more than double the roof unit. And anywhere in the rig was far cooler than the roof unit.

Learned me about how bad manufacturers lie.

Efficiency and RVs do not go hand in hand, Anything "RV" is pretty much as inefficient as you can get.

RVs have very little insulation (R3-R4 in walls, R2-3 in floor, R4-5 in roof, most have single pane windows, 1 inch thick doors with R1-2, pretty much 100% of your AC cooling or heating leaks right out of your RV..

AC efficiency is the least of your problems and really just because you may be running it off a generator will amount to a hill of beans no difference in fuel costs between EER of 9-11 ratings.

You do need to look at a couple of differences in construction of window air units and RV roof airs.

Window units can gain some efficiency from splashing the condensate on the outdoor coils, this splash helps reduce the refrigerant temps by the water evaporating off the coils allowing for a smaller outdoor coil and higher efficiency. Window units also are often placed in a window midway between to roof and ground, much cooler place and if you can away from the hotest point of the home.

RV AC units do not use the condensate splash, they are also mounted on top of the roof which is the hottest place on the earth.

If generator and fuel usage is your concern, might as well give up camping in a RV, I have not found any way to save money with a RV, it is a costly hobby.

My suggestion, don't worry so much about the cost of fuel, if you really want to camp, find a shady spot, open the windows and allow the breeze to cool you or just run the AC and gen and stop worrying about every nickle spent, otherwise you will drive yourself crazy trying to milk out every penny you can find.

You can't put a price on a hobby or the enjoyment that you get from it.

If you are looking to get better cooling in your 32 foot unit with 1 roof AC---Ain't gonna happen. 32 foot RV's need 2 roof AC units to cool correctly. Doug

It is. however short of going to the spec sheet for every maker I do not know.

To calculate watts - multiplying the amps by the line voltage.