$ savings would we have if we put window ac/110 in bedroom at night with our central ac on 85, 1680 sf house?

Question

$ savings would we have if we put window ac/110 in bedroom at night with our central ac on 85, 1680 sf house?

Answer 1

i know when our central air conditioner broke and we used a window unit are electrical bill was half of what it normally is. But we fixed the a/c.

Answer 2

Seems quite reasonable, my dad did the same thing to be more comfortable at night without overcooling the whole house.

I'm not sure I'd put it as high as 85 though, that makes for quite a load to work against the next day.  Also, running A/C at night is more efficient because the condenser (outside unit) is operating at much lower nighttime temperatures.

It's usually not a good idea to have extreme 'set ups' for central A/C, just takes too long to recover, especially if the 'set down' is happening during the heat of the day, when the efficiency is lowest.