I had 4 solar panels, four deep cycle house batteries and a high quality inverter professionally installed on my '07 27FB. It will run all my electrical demand, 12volt and AC, except the air conditioning.
I use microwave, coffee maker, Satilite TV, Stereo, lights, water pump, heater fans (as standard AS equipment), and some smaller items like battery chargers, etc. I am careful to only use the coffee maker to brew and use a thermos to keep the coffee warm all day. Heating elements like those used in coffee makers, hair driers, curling irons, toaster ovens use alot of electricity when left on.
My water heater is propane. And I doubt the solar would keep up with the demand if the heater were electric because it uses so much electricity while heating. I thought all AS water heaters were propane?
The trick to using solar successfully is knowing how much electricity you use and matching your storage capacity (battery capacity in amp hours) to the usage. Then matching your solar panel size and number of panels to the batteries. You will also need an inverter that can meet the wattage demand of your electrical appliances.
If this sounds complicated, well, it is at least very technical. I would only approach this with the advice of an RV/solar professional. The system I had installed is a good one, and meets my electrical needs, and is a bit pricey. It's been reliable. When boondocking, I don't have to worry about running the batteries low. If I need air conditioning, I power up the propane generator (I live in Florida, summers are hot!).
Lewster installed my solar. He can be found on this forum. I highly recommend him.