Every time you buy a house with a professional agent, you will be disclosed the rules, regulations and costs of air conditioning. That way, you're aware of replacement costs effected by the 2006 CA Dept of Energy ruling that requires local permitting of ductwork efficiency. (SEE ARTICLE LINK BELOW)
It costs more to replace units and ductwork than it once did, so "flippers" no longer put in CH&A, but fix it instead.
I think it provides buyers knowledge of potential future costs, reassurance that a newer unit has been put in professionally, and the overall community benefits of knowing units are more energy efficient.
http://www.bizjournals.com/sacramento/stories/2006/02/06/focus4.html
