Also as Bill suggested make sure you have a proper vent fan with exhaust, venting to soffit though is last resort in our area ( north east ) due to sending warm moist air out which gets blown back up into the soffit and creates mold and moisture issues on the underside of roof deck.

Wood structural panel roof sheathing exposed to the underside may be of interior type bonded with exterior glue, identified as Exposure 1.

Also since you said in that climate shade is not essential I have used sunshade fabric on tracks attach the underside of the top of a wood pergola type structure with a way to pull the sun shade material out on the tracks so that you can have it shaded or open. 

Dont ask me how I know,,,but,,,its sharp and likes to punch holes in your under side of your forearm. 

Poke your head in the attic with a flashlight and look for water stains on the underside of the decking.

To increase the life of the compressor, the underside of the refer should be cleaned out on a regular basis.

We read the remotes and the underside meters every 3-4 months and check them against each other.

You could add mineral wool or batt insul to the underside of the floor to catch the should.  

You can use blown insulation or you can get a 2 lbs. closed cell polyurethane froth pack from Foam it Green spray foam insulation and spray the underside of the roof.

Hellomy Brrrr house spends high utility bills($400 per month in Easten canada) and I'm thinking putting 2 inch foam insulation under siding when i install new siding.