I have a 10 year old Trane system. It is a 3.5 ton unit, 10 seer with a TWE042C14 air handler. The house was purchased with an unfinished room over the garage which has now been converted to a finished room. All in all, the house is now 2500 sq ft,(2000 before). I have a leak in the A-coil in the air handler which I have had techs out to service twice this year,(added 2 lbs first time and 1lb and a half second time). They say the coil is leaking due to rust and corrosion, the framework of the coil has some rust on it but they cannot pinpoint the leak. Now they haven't done a leak test..just used a sniffer to say "yes" theres a leak. Then they try to sell me a new system. The system cools fine as long as there freon in it.
Now my question is this:
Do I just need to get a replacement coil.
Or would it be time to upgrade my system to a higher SEER unit. Being that I finished the room over do I need to bump the system up to a 4 ton unit? That room does always seem to be a bit warmer in the summer and cooler in the winter.
I look forward to your thoughts.