"csonsini" wrote in message ...
We received a bid for adding a 500 sq ft
room.
Included in that bid is $5500 for a 2nd a/c unit and furnace.

I countered by saying
that we paid $3200 for the units that we currently have - and that's
for our entire house...how is it possible that we'd have to pay $5500
for 500 sq ft??? Of course, they didn't really know what to say.

Is our current set up sufficient for less than 1400 total square
footage? I know the "rule
of thumb" is 500 sq ft for every 1/2 ton,

Rules of thumb can be tossed out in many cases. Proper calculation is what
is needed; accept nothing less.

If $5500 high? Maybe, but I can't see what has to be done. How far does
the power (gas? electric?) have to be run? What about ducts? Piping?