Yeah, more info needed. I'll ASSume you have a standard furnace and need the pvc flu ran, and you have A/C so we can tie into the drain there, and the house is decently efficient (no big holes in the side right?). I am also a Trane dealer, and I'd probably go with an 80,000 BTU 90+% eff. furnace. As long as the sheetmetal work is not excessive I'd be around $2300 installed. You can also upgrade to 2 stage and 2 stage variable speed furnaces, which are more of a "luxury" model, meaning they aren't really more efficient, but will be quieter, and provide a more even heat, and the variable speed model can help with your A/C's performance. I would strongly recommend replacing the entire system at one time, unless your A/C system is newer. You will get a better deal and save yourself money in the long run.
Estimates are generally free. Contact some local dealers and use name brand equipment, i.e, Trane, Carrier, York, American Standard, Bryant, maybe some others. I have worked with almost every brand available today and I honestly prefer Trane, its been more reliable and has excellent factory support should you need it.
Get several estimates and do not be afraid to ask questions. If the salesman gets bothered by the questions, go elsewhere. And ask your neighbors who they have used, could be very helpful. At the very least it may steer you away from the bad ones.
