Hey there,

We live in central Indiana in a 1920s brick colonial -- no insulation in the walls, a few inches of cellulose in the unfinished attic. The house is about 1700 square feet and currently has a newish Lennox 2.5 ton AC, but while earlier owners put in plenty of returns downstairs there are no returns upstairs. (There is a supply in each room upstairs -- I'll put a copy of the upstairs floor plan, about 750 square feet, at the end of this post.)

Anyway, in the summer there's a noticeable difference in temperature and mugginess between the two levels, and I really hate the idea of making the downstairs freezing during the night just so the upstairs is bearable. We also have a baby coming soon and I hear they're temperamental when it comes to temperature. So we're considering putting a second AC in in our unfinished attic with the idea that it'd allow us more comfort and more control. I'd love any advice you have about this idea, and I have some specific questions, too.

We've gotten three bids -- the two I'm still considering are in the $4800 range for the labor, new condenser, AC unit, fan, ductwork, and a low-powered electric heater if we ever need to supplement in the winter. (The salesmen have all said what we'd probably do is just run the fan in the winter to better draw up the downstairs air, which is heated by a gas furnace.)

So first, does that seem like a reasonable price? Second, based on the floor plan below, would you put a supply and a return in each room (one bid's proposal) or just put a supply in each bedroom and a bigger return in the hallway, near the stairs (another bid's proposal)? I imagine we'll be shutting the doors more with kids, but there's a big gap between each door and the floor since the previous owner added carpet and tile, which we removed to go back to the hardwoods.

Third, how much do we need to worry about the ductwork and unit being in the very warm attic, outside the house's "envelope"? We're thinking about finishing the attic down the line, which would mean spraying foam insulation in the rafters; if we don't finish it we'll still blow more cellulose in. Both bids include insulated AC housings and flexible insulated ductwork. But I want to make sure the unit will still work well when everything is in a much warmer place than what it will be cooling -- and I hate thinking about all the wasted energy from such an arrangement, even if we end up fixing that problem down the line.

OK, sorry for the novel length post! If I've forgotten to add any details please let me know. And thanks for taking the time to reply!

Best,

Craig