Portable generators are used in homes and in places where there is no power or the need for power is minimum. Portable generators are generally smaller and are designed to use for a few. A portable generator of 5KW has enough power to keep lights, refrigerators, computers and televisions running for 7 to 8 hours. Portable generators are normally powered by gasoline, diesel, propane or natural gas. They are the most popular of all portable generators. Gasoline generators are relatively less expensive but require frequent maintenance and have a shorter life span. Gasoline has a short shelf life and cannot be stored for a long time unless treated with stabilizers.

Diesel generators, on the other hand, are fuel-efficient, consume less fuel per kilowatt of power produced, have longer life and require less maintenance. Diesel can be stored for longer periods of time. However, they are harder to start in cold weather and noisy. Portable generators powered by natural gas or propane is the best choice if available. The generator lasts longer and burns cleaner.

Before choosing a portable generator, the total wattage of all appliances to be powered by the generator must be calculated. This includes the starting wattage required by appliances with motors, such as refrigerators and freezers that use two or three times their normal wattage power to start. The generator should not only meet the normal wattage, but the start up wattage of the appliances. Moreover, the generator must have the necessary voltage ratings to run electric appliances such as the ovens and clothes driers that are rated at 240 volts. A portable generator should have at least two receptacles of 120 volt each. Generators that provide a longer runtime per tank of fuel or having a fuel tank capacity of around 5 gallon of fuel are preferred especially, by people living in areas where power failures are quite frequent.

A portable 7KW generator that can power lights, furnaces, sump pumps, televisions and refrigerators may cost $1000 or more depending upon the quality and the type of generator. For a normal home, an ideal generator would be in 10KW to 12 KW costing around $2700 for 10KW and $3700 for a 12 KW. Portable diesel generators are available for use on construction sites in the range of 200KW and more.

Before operating the generator, read and follow the instructions given in the owners manual. Observe the operating and the maintenance procedures strictly for safe and trouble free operation. Avoid putting loads on the generator that exceed the manufacturers rating. Also, do not run too many devices at the same time. This trips the generators circuit breakers causing loss of power. The generator must be operated at least twice a year with full load to keep it in working condition. Keep the generator outside the house but never in a garage or in a basement. Carbon monoxide emitted from the generator can be hazardous to health. Use only the recommended extension cords for the generator. Hire the service of a qualified electrician to install a transfer switch if the generator is to be connected to home wiring. Do not refuel the generator when it is under operation. Spilling of fuel may cause fire. The generator should be kept dry and should not be run in wet conditions.