I must say I don't know anything about A/C systems. I bought the house one year ago, and I am Italian, and nobody (more or less) has central A/C in Italian homes!
Today I called a contractor (which apparently has been in the business for about 30 years), and he confirms there is a serious leak. He also found one in the external unit, which is also a bit rusty. He checked with a "weird" tool that started beeping like hell when a leak was found. He thinks I should replace the whole thing (without being pushy about it), and gave me a quote of $3800 including taxes, installation, two years of free service, a 10-year labor and parts warrantee, and a programmable digital thermostat. I think it's a 12 SEER, but didn't ask the brand. I am asking around, and I sort of understand that the cost sounds reasonable, for this kind of job, but I would really appreciate any advice on the matter. Should I ask for other quotes? I live in Durham (North Carolina). Thanks a lot for any information anyone can give me! Have a great day, Alessandro Tarozzi