Mini-split is the best option for heat and cooling. It's the most efficient. Look into Daikin. It's the global leader for this type of unit. They have very high seer ratings and are much more affordable then the more popular options here in the US. I run a 9000BTU unit that's 18 seer. In my first shop I didn't have air cleaners running but I had a very good filter setup for the unit. The unit got a lot of dust in it through even the smallest of air leaks. In this shop I don't have any filters installed on it but have 2 air cleaners running. They are positioned so that the suction is near the mini split and exhaust away from it. The mini split has stayed fairly clean like this. Of coarse it also helps that I'm now using Festool sanders so there's a lot less fine dust to control.
Just a few ideas about the above install.
I would have installed the indoor unit much higher on the wall. That would allow for better airflow and mixture of the air in the space. It's not a big deal but would make a difference.
I can understand putting the outside unit on a stand to keep the coil cleaner. It's actually a very good idea. I suggest to customers to mount it on the side of the house. They make mounting brackets for that. These units only require a few inches clearance on the inlet side for airflow. I certainly hope that is treated lumber that was used to make the stand for the outdoor unit. That plywood is going to rot long before the unit needs to be changed.
Why put the roof over it? A roof isn't needed unless there is a danger of falling limbs hitting the unit. Your particular setup doesn't inhabit airflow. However, if you're using the mini split more for heat then why block the sun from hitting it. The unit could absorb the solar heating and transfer that heat into your building. I assume that the unit wasn't put closer to where the line set comes out because the roof would have blocked the window? Always use as short a line set as possible.
Other then those points the install looks extremely good and very professional.
FYI, if anyone has a roof or deck over an outside unit that blows the air straight up then you should either remove what's above the unit or relocate your unit. You're not helping the life expectancy by protecting your unit from the elements because these are designed to last a long time when exposed to the elements. What you are doing is inhibiting the airflow and reducing the efficiency of the unit. The roof or deck forces the unit to recirculate the air causing the air being used to get hotter during the summer months and colder during the winters months (for heat pumps). This will reduce the life expectancy of your unit because it's raising the pressures in the system making the unit work harder.
