A generator is an essential device for residential and commercial purposes for it is an important back up tool when a power source is cut off. There are different types of generators that can be used whether it's residential or commercial. Your local generator dealer has different types of generators of different wattage capabilities according to the needs of the individual. Buying the right type of generator depends on the number of factors like the wattage capacity, level of noise generated from the machine, portability, and price. There are many types of generators available from your local generator dealer. A standby generator provides back up power for homes and offices and they are permanently installed outside the house of office building. The residential generators start at 6,000 watts while commercial generators start at 30,000 watts. They are plugged into the electrical circuits and it turns itself on and off automatically when it detects the disruption of the electrical flow from the main electrical supply. The unit often uses propane and natural gas as the source of power for the motor to run. The generator motor in for the standby units tend to heat up. It needs a cooling system to prevent the unit from overheating.