Choose your contractor carefully. If the furnace isn't sized correctly not only will you suffer from discomfort but you'll also pay a higher price for operation. In contrast to some opinions expressed on this site, if your ducts are too small for the blower installed, you'll pay a premium for electricty to run the unit. This is doubly true for a variable speed blower because it will try till it dies to move the CFM's it's been assigned to move. How do you avoid getting the wrong contractor who puts in the wrong furnace? Do your homework. Congratulations on starting with this website. You'll find it's got a lifetimes worth of highly skilled and knowledgable professionals. We don't always agree with products or brands but we always agree on the right way to do it. Read my attatchment and I know you'll find the right contractor and avoid the discomfort of trying to reinvent the wheel.
If YOU want change, YOU have to first change.
If you are waiting for the 'other guy' to change first, just remember, you're the 'other guy's' other guy. To continue to expect real change when you keep acting the same way as always, is folly. Won't happen. Real change will only happen when a majority of the people change the way they vote!