Split-level house - 2,900 sq feet. Essentially, street-level; middle-level (living room); and upper level (bedrooms). AC contractor came in to give me an estimate - said that installing a new unit just for the upstairs and dedicating existing unit just for middle and downstairs is not cost-effective. Cost for just adding a zone (e.g., dampers, etc) would cost an additional $2,500? and that it would take a very long time to recover that through the cost savings in electricity by adding another zone.

He said he could offer me dampers and all but it just would not be worth it.

General thoughts on cost of zones versus time to recover in savings with electricity?