We are replacing our existing package unit as part of a remodel/addition. We're going with 2 systems (Trane equipment), one in the basement and one in the attic (2 story house).

This is an older home, built in 1935, so it is not the peak of energy efficiency, to say the least. We've done what we can to improve that, but until we replace the rest of the windows, and get better insulation blown into the walls (brick exterior), I think we are going to have hot and cold spots no matter what type of system we use. Am I wrong? And before you ask why we are doing an addition instead of replacing the windows and adding insulation to the walls; we need the space more than we need perfect comfort. ;-)

Given that, is it really worth the money to go with variable speed furnaces, or even just 2 stage, and 14 SEER AC? Just about anything would be an improvement over what we have now. And going with the VS and the 14 SEER is about 25% more expensive (several thousand dollars) all added up and this project is already going to tax the budget.

So, is it worth it? I've read the marketing material and listened to the HVAC guys but I'm not entirely convinced. Am I missing something? What are the real benefits?