There is no set amount required by different AC units, it may be listed on the mfg. tag on the unit but that is just the factory charge and may be different for lines over 25 feet. The freon in older home units is R-22 and isn't avilable to non licensed people. If your unit needs freon, it leaked out. someone should find the leak and give a quote on fixing it. If you are not licensed, it is illegal to sell you freon for private use. It is best to pay someone to take care of this task and then you will be more certain of having a working air conditioner. They have the training and tools to do a proper job.
No
If your air conditioner blows air but it's not cold air then you probably need freon in your air conditioner
$100
29 dollars for refill
Yes you can if you have the tool, knowledge, and of course the freon. Youtube has instructional videos to help you.
Actually no technical skills needed to check the Freon level. Home central air conditioners have a Freon scale on it. One just need to read the scale and determine whether the level of Freon is sufficient.
Go to your nearest HVAC&R distributor present your EPA Certification card and purchase the refrigerant.
Depends on the size of the unit and when it was built. Modern A/C units contain no Freon (R12). It was banned in 1996. Call a home A/C professional.
blue
5.1 Lbs
after twelve thousand years, so don't worry
No easy way of doing this. These units do not come with service valves.