Added value of a new HVAC system

[Alex Baev]

How much value does a new central air system add to a property in your area?
Assuming the house had nothing but a gas wall heater (required by code), and you're putting in a complete HVAC system, with ductwork, compressor, furnace, permits etc. - so central heat and air.

For reference, i have a 3 bed 2 bath bungalow in North East Los Angeles that i'm about to finish remodeling, and am now contemplating new central air in. For a property to be marketed as well as accepted as a "nice remodel" in my area, central air is a must. Plenty of older homes in the neighborhood still have window AC and gas wall heater combo, but in a remodeled house it wouldn't be acceptable, based on the recent rehabs i've seen. Clearly, there should be value in adding this feature, and doing so properly and with a permit, so that it's reflected in the title, and i'm trying to gage how much would be acceptable to spend on central air.
I've been quoted between $7200 and $16K for a 3Ton complete system, and while i don't always go with the lowest bid, i'm tempted to do so this time since i treat air as a "commodity" and not "finishings" and am at the tail and of a renovation.