Something to consider with caravan air-conditioning our air con man alertedus to.
The lowline models are generally noisy in there operation as the compressor is on it's side and dearer in price.
Where as the taller version are cheaper and quiter.
We had a failure with ours and I was ready to buy new tall one but as I had a real gentleman air con man, for a couple hundred dollars save it and 3 years on going better then the first year or so on our secondhand caravan.
I replaced my 12 year old Dometic with a ibis 4, mainly because of noise & start up capabilities. The ibis 4 has inverter technology so uses less power on start up. I find it quite to run unless of couse the fan is on high but once my Motorhome is cooled I only need the fan on low. I changed to a enerdrive lithium battery management system so I am able to run this air conditioner from my lithium battery & inverter set up which was important for me.