That evaporator coil is a 2 ton coil. Do not mismatch the evaporator coil and the condenser coil. Besides mismatching size, you will end up mismatching the energy efficiency rating. That coil is what's called a 10 Seer coil, and nobody makes a 10 Seer coil anymore. The lowest you can go is a 13 Seer system. I would go ahead and do everything right the first time, that way you will not have any issues with mismatching the system.
Also, if you get a free estimate from someone, see if they can do a manual J load calculation on your house to make sure the unit is not undersized.
A very rough way of figuring out whether you unit is big enough is taking the square footage of your house dividing that number by 600. That will be a somewhat close estimate to what size unit you need.
Performing a manual J load calculation is much better because they account for the windows, doors, insulation, and position of the house.
Hope this helps.

tlewis:

thanks much! home is 2200 sq.ft. west-facing, colonial two-story which, at first glance based upon the formula you have mentioned, would put me at 3.66T. we live in the midwest (ohio) and have roughly a 5 month cooling season, so it's pretty important that the new unit be sized properly. i will check into getting a load calc done to be sure, but can i firmly conclude that 2.0T is just way too small? like i said, the furnace does a great job keeping up on cold days, so at least i know my system has the capacity in terms of air flow.

Can't confirm a system is too small without a load calculation done, but 2 tons does sound small for your size home. Increasing the coil size won't make the 2 ton cool better. If anything it will decrease its ability to remove moisture because it will run warmer. I wouldn't mismatch the coils, either. You're probably better off with a new properly-sized A/C system.

thanks for the pointers ryan. i am thinking about biting the bullet next spring. i did some checking online and saw a Carrier 3 ton 12 - 13 SEER R410A cased coil and a Bryant condensor (supposedly a matched setup) for $1500 (on e-bay). I will probably be in the house another 6 years or so, but don't want to buy crap. service tech changed the board and blower in the furnace last year and it runs just fine. just need a decent unit to make my house cold. any recommendations on a condensor/coil...with the consideration that the furnace might puke out within the next 5 or 6 years? i did a pretty close load calc using some online resources and came up with 3.49 ton needed for my house. i didn't fudge too many numbers...

The problem is going to be moving almost twice as much air through (supposedly) 2 tons worth of ductwork, assuming it was sized right to begin with. I would not trust an online load calculation. You want an ACCA-approved Manual J load calculation done by a professional, then your ductwork inspected to see what needs to be done. That would be the best way to do it. Good luck.

please pardon my lack of understanding. i think i'm finally getting it though. are you saying that because i would be increasing the tonnage of the AC by 50% (from 2T to 3T as in the above example), that i need to assure that the air flow and ducting is sufficient?

many thanks,
j

J, you got it. Without sufficient ductwork, your new system won't deliver the expected performance and capacity, and may not be much better than what you have now. I haven't seen your ductwork, though; I'm just stressing the importance of a professional evaluating your whole system and doing a load calculation to determine sizing, then making certain the new system will work with what you have now. Good luck in getting this taken care of.

thanks much. i will keep this in mind.

j