I am about to replace my upstairs unit (10yrs old Air King), it is a 2.5 ton 10 SEER. I have been quoted for a new 15 SEER 2.5 ton, and a 3 ton 16 SEER (2 stage). There is a $ difference. Is it worth the difference? It is about 2000 sq. ft. upstairs (guessing).
Second question, with the new system, should I go with the wifi thermostat, or get a new NEST thermostat?