We have had several quotes from different HVAC contractors in our area. I have 3 separate proposals all saying we needed a 3 ton system. I then called the person that installed the furnace and he said, we need a 3.5 ton unit. He was a trane dealer and recently did the install of the furnace on the home. I also had another Trane dealer come here and spent an hour measuring our home and determined we needed a 2.5 ton unit. I'm confused that there would be such a discrepancy and don't have a clue what to do. I have tried to get some referrals from people but being new to the area, we don't really know anyone. This is a new 2000 square foot home in Beaverton, Oregon.
1. What can happen if we don't install the right size unit?
2. Would it make sense to just install a 3 ton unit?