昨晚空调坏了，今早打圈电话请人修，捕到一个。人来了，查了说我管子一出锈了，freon漏光了。加了9磅freon，$100/磅。我知道的问题是AC一般需要多少磅freon？我的机子旧了找不到标签看不出牌子。

网上看到For example:

  * 3-ton AC or Heat Pump with a 35 foot lineset will need a total of
    approximately 6-12 pounds of refrigerant, to fully recharge from
    empty. This includes the lineset, coil and unit.

*Disclaimer*: This rule of thumb is VERY general and there are several
variables that come into play. My Carrier 3-ton system may use 4-5
pounds, while your Goodman heat pump may use 5-6.

昨天他们用秤称，我没看到起始数据，不知道他们怎么算。感觉被宰了。1.我不相信一天会漏光，白天也再用。2.还没充完的时候他们就坚持说要充9磅。