Is the variable speed DC blower motor on the Carrier Infinity 96 gas furnace
worth the premium of $800+ (Cdn) that I've been quoted over Carrier's
Performance 93 unit with the multi-speed AC blower motor?

I understand that the DC blower motor consumes much less electricity than
the AC motor. But if I intend to run the blower at low-speed continuous
only during the heating season, how long would it take me to earn back the
increased cost in electricity savings?

Is the Infinity unit really much quieter in operation than the Performance
unit?

Any other factors I should take into account in deciding whether or not to
splurge on the Infinity?

Any advice anyone can provide would be appreciated.