28 footer is a single A/C enough for hot summers?

Not only will Onan 4000 not run 2 ACs, they are installed on 30 amp rigs, which makes it difficult to just add another AC unit down the road where rig also needs upgrade to 50amp service. Go with single 15K AC unit or choose rig with 50 amp service from the get go.

lacofdfireman wrote:

dedmiston wrote:
Nice to see you back, Dave.

Thanks. Nice to still see ya as a Mod. Looking to get rid of our Motorhome and get another trailer. Full circle. Haha. Just surprised these longer tongue pull trailers are being spec'd with a 4K genny and wired for dual air but can't support dual air. Just doesn't make sense to me.

Keep shopping. That doesn't sound normal to me.

dedmiston wrote:
Nice to see you back, Dave.

Thanks. Nice to still see ya as a Mod. Looking to get rid of our Motorhome and get another trailer. Full circle. Haha. Just surprised these longer tongue pull trailers are being spec'd with a 4K genny and wired for dual air but can't support dual air. Just doesn't make sense to me.

My single 15,000 BTU A/C does great in my 38' overall quad slide TT. However, it's better insulated than most TTs and is white.

My 41' weekend warrior also had a single unit. It could maintain the inside just fine, but it was slow to cool an already hot trailer. Since it only had one slide-out, it had less air-leaks, but that ramp door can be a huge heat sink in the sun.

I suspect even that trailer is pre-wired at least.

In our 31 foot Springdale TT with no slides, the original 13,500 BTU air conditioner did just fine. Never had a problem. But we did not camp in 115 degree climates either.

Fast forward. Our 35 foot Outback with 3 slides and the original 13,500 BTU air conditioner just could not keep up (even in milder Indiana temperatures). We swapped it out for a 15,000 BTU because our TT is 30 amp and it would have been a major rework with the wiring to get it converted to 50 amp. So we went with the 15,000 and it's worked great ever since, even with the 3 slides.

I have no clue how a second air conditioner will run on your generator. I have a small generator and it ran the 13,500 just fine. BUT the 15,000 won't start with the generator now. We never boom dock, but I have the generator just in case. Actually use it more for the house when we have power outages than anything else.

This would be my advise, get a single 15,000 BTU.

We use a small swamp cooler attached to one of the rear vent doors on our hauler, works great with temps in the desert over 100. 65 inside with all windows and door open. On low speed too.

4000 is the listed minimum for a single air. Two would be marginal if they even start. But the new A/Cs are getting better so maybe a longshot but not impossible. Maybe 2x 13.5 high efficiency units. Or a 13.5 and smaller 9 or 11k BTU. Good luck.

If the RV is well insulated, parked in the shade, and you have a superior installation the single air should be fine. Reality is not likely as temps go 95+ if you want a steady 72 inside.

115F outside?
Not enough.

Onan 4000 will not run 2 units.

Nice to see you back, Dave.

Desert SW not enough. Canada north, more than enough.