By . Air Compressor. At Thursday, August 09th 2018, 18:58:16 PM.
All reciprocating air compressors throw out some oil with the air they compress. When the tank reaches its designed pressure limit, a switch will interrupt electrical power to the motor. Simultaneously, a certain amount of oily air will be released into the shop environment. You may see oil collecting on the wall behind the compressor and on the pump and compressor as well over time. This is not cause for alarm but periodic cleaning may be needed.
Oil free systems are a bit more technical so sometimes are more expensive. Often they are louder than an oil lubed compressor, but the air delivered through one of these pumps is of a better quality. They are found for home use, and are great because they are low maintenance and start up quick in cold weather.
Though this information may not help you a lot in deciding what actual brand and model you should buy, it should help you to at least recognize basic terms. That way you will know the best questions to ask an expert and maybe understand better his answers. That way you can make the best decision according to your needs. After all, the right air compressor will make a lot of your home projects a lot easier and faster to accomplish.