Game in the Brain

1) to guess the labor just check the number of man days the installer says. You will ask how long the work will be and how many people will work (for the condo or village permits). There is your manday. Typically (materials + labor ) / 0.6-0.5 in companies like mine. (So contribution margin is reasonably 70-100% so when a company charges like 180 for what I believe to be 20k thats too much)

1.1) Materials like Copper Piping, Insulation, and Gipsum (to putty up and cover the cuts they will make in the ceiling) can be pretty much guessed. Sizing of the Pipes and insulation is information that is FREE fro the Manufacturer.
1.2) Do not be afraid of a Detailed BOM or SOW.

1.3) https://makercise.com/diy-mini-split-ac-install/
1.4) Calculator https://www.ecomfort.com/stories/1439-What-Size-Mini-Split-Should-You-Buy.html?icn=What+Size+Mini+Split&icl=home+page+lower

2) in Anson each brand of aircon has a seperate set of installers who will inspect and quote. You can get 3-4 quotes just from one place.

3) Overspec is cheaper given the 5-10 years life of an Aircon. In its life it runs into problems. Its possible that its -20% efficiency over time. Heat load like additional occupants, guests, etc… have to be factored. If you have to turn it HIGH and Max all the time then you under-speced the Aircon. Once you have the Volume to HP ratio for the target Temperature and Occupants, you have to Spec a little higher (about 25% more HP; if it can Cool the room at Medium then good).
3.1) How much is lost sleep worth to you?

4) As a General Rule, a Plastic Clear Envelope with the, Warranty, Receipt, Manual and Instructions taped to the Wall means DAD is not the only one who can FIX things. Great for any appliance that is expensive and considered durable goods. // of course Wives hate that  Aesthetic.
(When the wife asked me what I liked in a home I answered – to look like a Toyota FACTORY – 5S and everything in order with elegant reasoning)

Sorry Manufacturing and Construction Background – I hate clutter and my parents insist in their own furniture instead of letting me and my team 5S the damn thing. And 5S is not “Designer Pretty”.