I am installing a new HVAC system in my home and have three bids from Rheem, Amana and Carrier contractors. The home has approximately 2,000 s.f. and I am going with 16-17 SEER A/C, 95% Furnace ratings. One of the contractors is suggesting going with 5 ton system and the others are at 4 tons. Is a 5 ton system overkill? Is Amana a good product? I am hoping to get responses. Thanks.