What would be the approximate cost to replace the a-coil in a 3 1/2 ton unit. I have an appraisal for $1800. This sounds expensive.

Don't know labor rates where you're at but I would get 3-4 estimates. If they all come in close you will know that is a fair price. T here is a lot more involved in changing coil than meets the eye. Must remove old, rebraze lines, pull a vacuum and recharge unit etc.

I agree, get a few bids, that seems kind of high. Be very carefull though, don't go with the lower bid just because it's cheap, find a legit company that will back their work.