Post model number of furnace and model number of evap coil.

Installing evap coil was a mistake.

What is typical summer temps for your location/climate?

IMO

I don't think the Bay area gets very hot in the summer, so I would think a 3 or 3.5 ton AC would be sufficient for your 2000 sq. foot house. Look for a HVAC contractor who will do a heating and cooling load calculation. Otherwise it is just a guess and you will not be comfortable nor efficient.

It is not uncommon to see a 4 ton coil with a 3 ton AC condenser. I suggest you have the contract put together and verify it is an AHRI matched system.

If you post the model number of the furnace and coil then we could figure out what condenser may be a good match. But first the proper size will need to be determined.

As a side note builders typically don't know anything about HVAC sizing or installation. Hopefully the equipment you already have will not be a problem.

thank you, i will post numbers later. it is not too hot where we live- average summer high temp around 80, though we occasionally have some spikes. most friends in the area say they use their ac 10-15 days/year.

i was particularly concerned that a 3.5 ton ac would not be compatible with a 3 ton furnace/blower.