There are many opinions on coach air conditioning, whether you should keep the original or not, look at ELV systems if you have the capacity to run them, or do as we did and fit domestic split system airconditioners, reverse cycle of course so no diesel heater needed. Even when the decision is made to go for split systems, you then have to decide if you will use one bigger head unit, or 2 seperate complete systems, which is what we did. Of course if you are going down either of these roads you need thew oopmh to drive them and that is where our energy system comes in. There is no point in going over that again, here, it is all covered in the appropriate section so please check that out.
We decided on 2 x 2.2 Kw Onsen units supplied by Reece who we deal with a lot. They are very energy efficient, and once a room is down to temperature and fan speed is down to low, only draw about 2.5 amps of 240 volt power, of course that is 25 amps coming from the Lithium battery pack. They have proved to be a good choice, although in the future I would ft units that had drains both sides, we had to pull the front one to epoxy an additional drain in it. Size is ok as we are only in one or the other half at one time (living or bedroom) and the units we have are easily capable of cooling or heating the area they are installed in.
A gallery of pictures of the front install is below. We had to do this one early so we could move forward, as the pipes and cables connectiong the two units are now covered up
The second gallery shows the install of the rear aircon. The outdoor unit of the split system is in the engine bay. I am coming around to the idea of having a single outdoor unit big enough for 2 aircons, mounted in the bins somewhere, but that was not how we installed ours.