As you know Tuga, I have 4 roof top air cond on my bus and just returned from a 3 week trip up to Michigan and Wisc. Of course it was cool there but extremely hot going up and back thru MS., TN. KY, IL, AR, IN, MO, AL and on the road never ran anything but Dash air and one roof top unit off of the invertor and never had problem with heat. When parked at night ran only 2 roof top units. I am happy with performance and the fact that they can be replaced so cheap. No problems to date after 11 years.
Danss 1999 Vogue, 03 Chev. Trailblazer