There are many physical configurations of the electric units. Some look like upright vacuum cleaners with big plastic wheels. These units have capacities ranging up to around 4.5 gpm and up to 3200 psi depending on manufacturer. Larger portable units have metal frames and wheels for portability.

There is also a box style which has all the components in a metal protective enclosure and optionally has wheels on it for added mobility.

If you are in remote locations away from AC power or in new construction where AC power is not easily available, then a gasoline powered cold water pressure washer may be just the unit for you. These units also come in diesel versions for locations where diesel fuel is more readily available.

These units are for outdoor use only. These pressure washers come in a wide variety of mounting styles. There are units that are hand truck mounted style, cage style with wheels and skid mounted without wheels. Each style has its application.

Both electric and gas powered cold water pressure washer types have two available drive configurations. There are direct drive units and belt driven units. The direct drive units are lower maintenance. The belt driven units have a longer life due to the fact that vibration from the drive motor is not transmitted to the pump. The belt helps to isolate the vibration and extent the life of the pump. Direct drive units are more compact and are also more economical (read cheaper).

If you are using the pressure washer for several hours a day, 7 days a week, then you will want to choose a belt driven unit. For those of you who use the unit once or twice a year to wash a car or wash the house and/or deck, a direct drive unit is a perfectly acceptable and appropriate choice. A great deal more pressure washer information is available at Gas Pressure Washer HQ.