I feel your pain, for years we had no aircon , was hell trying to sleep during scorching hot/humid days when I'd been on dogwatch (midnight - 8am shift) in summer, and not much fun sleeping on the really muggy tropical nights when there was no breeze and it was like 90oF all night with very high humidity.
Then I invested in a window mounted aircon (a Kelvinator 1/2 HP) unit , boy did it make a racket , but it did a great job at knocking out the humidity and cooling the air so made sleeping possible (only good for one room !! though)..
Then when we got married and bought this house , no double hung sash windows , all horizontal sliders or those horrible awning style windows.
So I cut a hole in the N wall of the master bedroom and mounted the old window mount aircon in the hole ... solved that problem ... but the sound really amplified in the wall cavity !!!
You might be able mount your aircon like this
http://www.instructables.com/id/Installing-AC-unit-inside-of-a-horizontally-slidi/ in your slider windows.
'
Eventually I splashed out and had a 3.5 HP Fujitsu Split Air Con installed in the living area (lounge - dining room + kitchen) while I was renovating the house , 3.5 HP was about 50% larger than I needed according to the salesperson , but I wanted a unit that would never struggle to heat / cool the entire house.
Was a huge house renovation , managed and a lot done by me by myself (though I hired a builder to do to the really heavy lifting) , comprising removing asbestos cladding, insulating exterior walls and ceilings with fibre batts and recladding with HandyPlank, rippng out the original kitchen and bathroom and changing some interior walls , recladding some interior walls s with timber panels, upgrading/redesigning bathroom and kitchen, replacing all the old timber awning style windows with aluminium sliders and double hung window , replacing all the old interior doors with new doors , new solid timber entrance doors + securioty doors + monitored alarm system + putting up a double garage ) , took about 3 months ....
Best investment ever IMO .... and not all that expensive to run if you run it 24/7 .
First split unit lasted 25 years , compressor eventually died, now we've a 3HP Inverter Model (same brand , some heating and cooling power as old one , lots quieter ) and had it for about 4 years and love it. This is what we have
https://www.fujitsugeneral.com.au/product/astg24lfcc-with-aotg30lbta4?category=Inverter Multi - Wall Mounted
There are split aircon that run 2 or 3 wall hung units powered by a single exterior compressor that are good value , cheaper than ducted aircon and much easier to install (only requires a small hole in the wall for the plumbing and cabling) . ie
https://www.fujitsugeneral.com.au/commercial-range/multi-type-system-c
Frigidaire makes Slider Casement units that provide 8,000 to 12,000 BTU cooling capacity for rooms up to 640 sq. ft. Korean manufacturer LG (who makes many of Sears' Kenmore air conditioners) offers a 10,000 BTU vertical mount unit for $339. And then there is a range from Fedders, which claims to fit windows from 21"-40.5" high and needs 15.5" minimum in width. Just make sure you study up on matching the specifications of the unit with the size and cooling needs of your home;