[justjim]

Originally Posted by Battlebasset

Like others, not saying you shouldn't do this. But maybe do a test where you drop your temp for a month to 68 at night for your whole house, and compare it to what you pay per month when you don't drop it. Pick a couple of the hottest months for the max comparison.

Let's say the difference is $25 per month. That means 100 months, or 8.3 years you could do that for the $2500 you would spend on the split system. And if you are thinking "But that will kill my house AC quicker" well perhaps, but then you have $2500 in your pocket to put towards a new house AC,

Not perfect/apples to apples, but at least you would be going into the purchase with an idea of what your $2500 purchase gets you vs just turning down your existing AC a bit.

I like your thinking! I know in our case it would not be profitable because the difference is 75 in the day and 72 at night. 68 is just too cold for us at night! But to each his own.