1. how old is the old AC unit?
2. ARe you moving it (the old one) from the roof to the sideyard?

If #1 is 'over 10 years' and #2 is true, you should replace the old unit considering the costs involved.

Thanks for the help.

I'm not sure how old the AC is, but somewhere around 5-10 years seems about right. It looks to be in pretty good shape. It's an Amana/Goodman, so probably not as expensive as some of the other brands. The cost of moving it to the sideyard and the new ducts/wiring/pipes are already included in the remodeling costs, so that won't play a big factor. I'm just concerned that we might end up with a poorly matched system. I'm getting some bids on replacing the whole HVAC system to see if it's feasible at this time.

Do you have a multi positioning evap coil to put in the attic or is the new setup going to be vertical also?

Moving an old AC condenser is risky. I did this with a 20 year old unit. A freon leak developed after the move. I eventually replaced it with a new unit.

If the budget won't allow a new AC, then consider adding the matching condenser in the Spring. You may also be eligible for the $500 tax credit with a new furnace and condenser, plus local utility rebates.

I don't think I'll have enough vertical space in the attic for the existing furnace, so I'll have to go with a horizontal setup. Does that have any special issues vs a vertical setup?

It's a good suggestion about the condenser, especially since most of the work will be outside the house. I'll look into the rebates but we're already replacing the water heaters and attic insulation, so we may not be able to claim any more credit.

Thanks.

What state are you in? California utilities offer substantial rebates for whole home efficiency projects (covering envelope sealing and system upgrades).

I guess my question did not merit an answer. do you have a multi positioning coil?????? this is very important to the install procedure.

Sorry heat seeker. I don't know what kind of coil I have right now. I was told that I "couldn't" use the existing furnace in the attic because it would have to be placed horizontally. I assumed that meant I don't have a multi positioning furnace and/or evaporator coil. Thanks.

your welcome