Generators are handy machines to have around if you require a constant supply of electricity or face frequent power cuts. The ability to turn mechanical energy into usable electrical energy makes them an indispensable tool in construction sites, residential units, offices and camp sites.

Not all generators are large and expensive but those that are more powerful and generate higher watts. Two factors come into play when assessing power measurement - startup power and running watts. Startup power refers to how much wattage a generator can produce to start machines and handle peak loads while running power is associated with how well it can generate constant power during normal load.

Generator types

Generators are classified into what they're able to power, size, cost and portability.

Standby: Standby generators are used during power cuts to drive electrical appliances like ACs, refrigerators, computers, and kitchen appliances. They also serve industrial needs. They may be automatic or manual in that they may turn on automatically when the power goes out or have to be turned on.

Standby generators are quite large. They use fuel like natural gas or propane. Cost varies with wattage output but is more expensive than smaller varieties. Expect to pay between $5,000 and $15,000.

Portable generators: Small yet efficient, portable generators are ideal for home use. Depending on fuel supply and wattage, they can power refrigerators, televisions, computers etc. Where standby varieties generate between 7,000 to 30,000 watts of power, the portable kind delivers around 3,200 to 10,000 watts. Pull starts or key starts can be purchased.

Despite their small size, portable generators can have large fuel tanks to power them for up to 10 hours. Cost varies between $500 to over $1,000.

RV generators: Recreational vehicles don't have power lines because they're mobile. RV generators are the only way to feed power into outlets and appliances. Small, quiet and quite powerful, they do a good job of handling peak loads. Several tanks of fuel are required especially if there are numerous electrical appliances onboard. And just like other generators, some produce higher wattage.

Vehicle-mounted generators: Similar to RV generators but used for different purposes is the vehicle-mounted generator. It's much larger and more powerful and mainly used in mining and construction operations. The machines are typically mounted on trailers for quick dispatch to operations sites.

Wind generators: Wind generators for home, commercial and industrial generate clean energy. They're still relatively new compared to other types of generators but are slowly gaining ground. Batteries store excess energy for use when needed.

Solar generators: Like wind generators, solar generators deliver clean energy but using sunlight rather than wind. They've become a big hit with average consumers and commercial users. A battery stores excess converted energy for future use.

In view of the range of generators available, buyers should ascertain what their needs are before making a decision. Small doesn't always mean low power. They can deliver enough electricity to power furnace fans, refrigerators and other electrical appliances. Of course, larger models pack more punch and can restore power to around 10 circuits in a house. Even larger models have enough power to juice central ACs. Industrial varieties are huge and may need to be housed depending on location. Cost is very high so you won't find them in average homes.