Legal Question in Real Estate Law in California

Even though you bought it from the lender, any cause of action that the original home owner would have against the builder should pass on to you. It being the wrong size is not something you would be expected to notice. So you should be able to sue the builder for breach of implied warranty or that it is a latent defect but you may have a statute of limitations problem. You may need a letter from an attorney to have a chance that he will comply. You could sue in small claims court.

If the home is in 95382 (Turlock), you definitely need air conditioning. However, your question seems to call for technical, rather than legal, advice. I got a degree in mechanical engineering long before my law degree (1961 versus 1999), and my advice would be to consult with another air conditioning firm. You don't say what the problems with the a/c are, but if it is overloaded, your alternatives are (a) to settle for 77 degrees instead of 72 on hot days, or (b) to replace what you have with a bigger unit. That'll not only involve an installation charge (although $5,000 seems kinda high) plus high operating (electricity) costs. You might want to have an energy audit or some similar consulting service performed before spending big bucks. Maybe your present unit needs minor service, followed by raising the thermostat five degrees or so, or maybe you need a 25% bigger unit in terms of BTU per hour capacity. Overall, my adive is to get a second opinion, then be prepared either to throttle back your cooling efforts or invest in a bigger unit. Also, what's happened between summer 2009 and March 2012?