Forum Discussion
cannesdo
Aug 07, 2014Explorer
Golden_HVAC wrote:
Hi,
If it is 80F outside and inside, time to check the performance of your rooftop A/C unit. If it is taking in 80F air, then the output should be 18 - 22F cooler, or around 60F.
Thanks for the info, Fred!
That's in full sun. I believe my A/C is in good shape. The air coming out is cold. It's just that I have 36 feet of fifth wheel and a massive back window. 40 square feet of glass. Even if the sun isn't shining directly on it and the blinds are down it lets in a lot of heat. It's 63 in here right now and I just turned on the air to see what it was coming out of the vents with the probe and it's 54 degrees. (I'll check that again tomorrow when it's warmer. It's cold. It's just not enough. My rig is insulated well but with the skylights (which I block with foam core during the summer) and that big back window it will stay comfortable until early to mid afternoon, then it's a battle to just keep it at 80. if it's 88 to 90 I can keep it at about 82, but on any day over 80, in the sun, it will eventually hit 80 inside. Temp in the sun outside can be topping 100 at that point so it's not as hot as the outside temp but still, I'd like to be able to keep it at 75 however hot it is outside.
I think I just need a second smaller unit in the front. But I can't run the blow dryer, for example, when the main A/C is on, on 30A, so I am pretty sure for two I'd need 50A but that's not usually a problem. My other A/C is a 15K BTU. I know, hard to believe but most big rigs do have two A/Cs. It just turns into a cooker by afternoon then I spend the whole evening trying to get it cooled off.
I have an open vent with no fan in it in the bathroom area. Schematics show that was an option for that vent but the original buyers evidently passed on that. Does that mean it's likely wired for the 2nd unit already? There's an electrical plug inside behind the drawers below it which I use when I need to run two electric heaters at once. It's there for the optional wash/dryer which they also passed on. Do these A/C's in the roof every just run off a plug?
About Technical Issues
Having RV issues? Connect with others who have been in your shoes.24,367 PostsLatest Activity: Mar 10, 2026