I need to replace my heat pump (Carrier 2.5 ton) packaged unit. I got a price on a Trane (XL14c, 2.5t) which is good. Then I called my Carrier guy who I have known for years and he threw me a curve. He said it would be better to go with a 3 ton unit. His price on a 14 Seer is higher than the Trane. His price on a 15 Seer, 2 stage unit that has a good promo right now is only $600 more than his 14 Seer (single) and is $932 more than the Trane 14 Seer (single).

My house is only approximately 1000 sq ft interior. It's a wood frame cottage style, one level, with marginally decent insulation. Do I need a 3 ton? Is there much difference in operating cost over a 2.5 ton. From what I've read about a 2 stage system sounds good, but the 3 ton recommendation threw me. There are things I was impressed with about the Trane, but now I feel like I've been given apples & oranges to compare. Help please.