The water chiller was always on the cards because the automation kinda needs it and it just makes every thing so much easier when you can rule out any environmental variables. So a chiller and a water heater takes care of the water temp.
You certainly do not need all the crap I have to do hydroponics I just treat it like a hobby and half of the fun for me is the planning and the building, etc. I want to eventually be automated so this does involve some 'more expensive' components. i.e. the pH and E.C. sensors, shields, etc are way more expensive than the pH/TDS pens from Amazon (which I also have) but being able to both see and react to the various reading 24/7 is worth the money to me especially if I can eventually get it 'dialled in' to be mostly fully automated (hence the hydro approach in the first place). Even in soil you are still dealing with water and the ability to dump the complete system down the drain and refill automatically works and I couldn't do this with soil.
The air conditioning is on hold and if they get through the next couple of week OK I will probably not bother with it as it is too expensive and hard to get installed in the location I need it. UK weather is normally shit so just have to hang it out I reckon.
And NO, I don't do things by half mate; once I get 'one of my ideas' I just plan it out while getting stoned and that shit can be dangerous because you never stop planning.
P.S. 'legionella course' - done my head with that - no idea what that is - I'm gonna ignore that for now, pretend I don't have to worry and ask Grumpy or someone for advice if I get it ;O)