zoning system or 20seer system

[calimanmancali]

I have 2 AC contractor come to my house.the first one tell me replace the 4 ton American standard system 20 seer condenser and 95% furnace with the cost realy hight...The second contractor give me a very good deal with the system 3 ton American standard,15seer,80% furnace and 3 zone system(my house size:1700sqf)
Can anyone give me an idea which system is the best to go.thanks

[nike123]

Ask for more independent contractors bids and discard lowest and highest bid.
Than choose one that has best references. And, I suggest that you check that references. If you are lazy, than hire some consulting firm.