Generators are very common in rural areas. Most are simple machines, consisting of the horizontal version of big lawnmower engine spinning a "generator head unit". Generators are about the best bang for the buck when it comes to cost per watt and lots of watts are needed to keep food cold, people cool and showers hot. While researching a generator, it is important to understand what size, fuel type and noise level makes the most sense for your preparedness plan. There are endless features, some useless and others invaluable. Will pull start be good enough or is remote electric start the only way to go? Is noise from a loud generator going create a problem with the neighbors or can you already hear theirs running while you're in the shower? Do you have sensitive electronics or computerized appliances? The answers to these questions will help determine the proper back up power generator.

When shopping for a generator, the primary considerations are usually price, size and noise level. However, one of the most important and rarely considered generator specifications is total harmonic distortion (THD). THD is a measurement describing the quality of power the generator produces. Utility grid power typically has less than 2% THD which is a tall order to duplicate with a portable generator. THD ratings of less than 5% are achieved by numerous generators and is good enough for most applications. Less expensive generators can produce up to 25% THD under load and are best avoided unless there are no other options available. Look for an advertised THD of less than 5% when sensitive electronics are expected to be added the mix. Remember, if the THD rating isn't shown, the manufacturer doesn't want you to know.

Selecting the right generator also means choosing the fuel that will be stored to run it. For emergency preparedness, no other fuel matches the shelf life or versatility of propane. Due to the cost of the storage container, propane is more expensive but requires no yearly rotation, preparation or additives to keep it fresh. Propane does not gum up carburetors and will not become contaminated by water. Besides generators, propane is used in gas grills, lanterns, heaters and fryers. Propane is one of the most flexible prepper fuels.

Gasoline generators are most common and least expensive models on the market. Gasoline is highly flammable and requires an additive to help maintain freshness during long term storage. It is best to start with ethanol free gasoline and mix in an additive such as Stabilt gasoline preservative to ensure it remains fresh and ready for use. Gasoline needs to be stored in cool, well ventilated locations away from sources of heat in a sealed container. Though not as flexible as propane, gasoline is also used in cars, ATVs and lawn and garden equipment.

A diesel generator may be a good choice if you already have use for diesel around the house. Diesel can become contaminated with water, bacteria and fungus. However with preservative, the shelf life of diesel is much longer than gasoline when properly stored in a sealed container. It is used in some trucks, tractors and while combustible, diesel is not nearly as flammable as gasoline. Diesel generators are more expensive than comparable sized gasoline and propane generators. However, the costs may be offset if diesel fuel is already stored on site for other uses.

Noise levels are another consideration when selecting a back up generator. While there are no national regulations stating how generator sound intensity is measured, the industry has been consistent on taking readings at 23 feet. Most contractor open frame generators produce from 67-76 dB of sound intensity. For perspective, 76dB is also the sound intensity of a screaming toddler in a restaurant booth -also 23 feet away. For apartment dwellers, 70dB is an automatic non-starter. On the other hand, 70dB is not unreasonable during the day light hours as long as you're not bound by the oppressive chains of an HOA. Unless you're sharing power with them, the neighbors are going to grow tired of you at night. If whole house night time operation is a requirement, then a stationary standby unit (approx. 58 dB) may be the best choice. When the dB rating is not shown on a particular generator, it also shows the manufacturer doesn't want you to know how loud it is.