Yes you could install this yourself, if you enjoy bathroom fitting! You need to check you have enough space to install it against a load bearing wall , i.e. not a plasterboard stud wall. The unit will need boxing in behind a false wall that is accessible for maintenance. This must be a concrete blockwork or brick wall or other loadbearing wall capable of supporting 100kg. In front of the unit will need a false wall that is fully removable for maintenance, this could be tiles or wood panelling to suit your style of bathroom.You need to work out how to supply, by gravity, the condensate pipe from the air-con system into the top of the tank. The cistern has an overflow pipe at the top which needs to go down to a drain and also a fresh water supply pipe connection for back up (so one flush is always available even if the air-con is off.) Check the overall dimensions of your void space behind the false wall with the "Get One" page. The flush pipe is a standard size, 38mm diameter, suitable to fit a "back-to-the-wall" and "floor mounted" type of WC pan.
You will need to add sterilising tablets every now and again, we recommend once a year, to add 3 baby bottle sterilising tablets into a full tank and leaving this overnight. Generally the air-con unit condensate is very clean water, collected from moisture from the atmosphere, this should not cause any mechanical problems.