We recently got a new gas furnace, and had some troubles with the contractor (did not pass city inspection 4 times and got huffy with us and with the city). During some conversation with us, he told us that he could install the furnace in a way so as to make it easier to add AC at a later date. There was not any conversation about costs as I recall - in fact, I thought it was just something he did inside to make it more adaptable.
Later, we get an ADDITIONAL bill (after the first one) for an additional $425 for AC Coil.
Is this reasonable? SHould we pay it? We did not receive anything in writing, no quote, nothing... but I don't want to make the guy madder in case we ever have a problem with this furnace. We were wondering if he was taking advantage of us with this added charge, as he was upset about having to install a pump to take care of a water problem that caused him to not pass inspection...
Thanks!

I would say $425.00 is pretty close, without knowing the size of the system. In my opinion you are better off installing the evap. Coil now versus later, there will be more time and labor to tear back into the system.

Is the coil the contractor installed the correct size for the A/C system you will need?
Did he do a manual J to determine the size of the A/C unit you might buy someday?
Some coils will need to be adapted for different kinds(brands of equipment).
Expansion valve/piston flow raters are different for different manufactures and depending upon the coil design and outdoor unit requirements.
He could just have placed a door (access) in the sheet metal in the supply air side for a future coil. You did not have to buy the coil to have it ready for easier A/C install.
Will the coil match for the correct SEER value when you buy your A/C unit? There is a match up requirement!

The price of the coil seems reasonable but there are a lot of unanswered questions.

If you got a cooling coil installed for $425 it's a great deal if it's the size evap coil you need for your home. If you can give us a estimate of square footage on your home with the model number on the evaporator coil we can see if its close or not. Model number of the furnace will help.