What is the correct size ac system for 1500 sq ft

Need more info. What climate zone are you in? How much insulation do you have in your attic and walls? What type of windows do you have? You need to have someone run a load calculation on your home to see what size your house needs. Basic rule 2.5 to 3 ton. Have a few of the local companies give you a free estimate and see what they come up with. Good luck.

And shop based on SEER rating of minimum 13 or greater.