ReadinessHub.com Emergency Backup Generator Buying Guide During an Emergency situation that causes the power to go out, things quickly change. Most people do not realize how many parts of their daily lives are assisted by electricity. On average, a home caught without power will have zero function in: sump/water/well-pumps (subsequently disabling sinks, showers, toilets, etc.), lights, computers/internet, refrigerators (meaning perishable food will soon perish), televisions, electric thermostats and heating/ventilation/air-conditioning systems, and anything plugged into a power outlet. Most people will take electricity for granted until it is lost for a long period of time. In this guide, I will try to make the process of selecting and purchasing a generator more straightforward. Any questions not addressed in this basic guide should be addressed with a qualified professional electrician or power-pro technician. Types of Generators There are many types of generators available; however here are the main fuel variations: • Gasoline (MOGAS) Generators • Diesel Generators • Liquefied Petroleum Gas or Propane (LPG) Generators • Natural Gas Generators We'll also focus on the most common size classifications of generators and their accessories: • Permanent Home Standby Generators • Portable Home Emergency Generators • Commercial Generators • Industrial Generators • Generator Accessories Generator Fuel Types Fuel types found in generators varies from each manufacturer. Fuel type also reflects differences in pricing because of the different economical requirements needed to effectively process and consume the fuel. When considering fuel type one most consider fuel availability and the ability to effectively store that fuel. Gasoline and Diesel Generators Gasoline and diesel generators are usually the least expensive choice, but will require manual filling about once every 12-24 hours at half-load until the power is restored to the home. Although they are the most cumbersome they are the most available types of fuels and only require a proper container to fill, transport and store. Gasoline can be stored up to two years with relatively inexpensive conventional fuel stabilizers, found in a local automotive section along with fluids and oils. Gasoline is difficult to preserve longer, because most modern gasoline uses butane diffused within the liquid fuel to help the internal combustion engine start during ignition. Diesel fuel can be stored for up to ten years with the correct anti-bacterial agents. Liquefied Petroleum Gas and Natural Gas Generators LPG (propane) and natural gas generators usually require service to be brought to your house or business with a meter or a large storage tank/container be installed and plumbed. This requires high up front costs but the result is hands-free refueling. If stored correctly, propane and natural gas will be usable far longer than both stabilized gasoline and diesel. That is, if the tank or container they are stored in does not leak. Generator Types and Sizes Depending on the size of your home, the size and type of generator best suited for you will vary. Permanent Residential Standby Generators One type of commonly used household generators are Permanent Residential Standby Generators; one with an auto-start option can literally do everything by itself. When the automatic transfer switch of the standby generator senses a power outage it isolates the home’s electrical wiring or designated emergency circuits from input lines and starts the generator; When home’s power is restored the system will automatically turn itself off and allow the utility lines of the home to resume connection to utilities. Technically, no one has to be home to activate this type of generator. However, the typical transfer time of an automatic standby generator system is 8-35 seconds. If you maintain important computer functions or programs you may still need a UPS (Uninterrupted Power Supply) backup system to prevent data loss during the transfer time. These permanent residential standby generators require professional installation and generally use either LPG or Natural gas lines fed into the house. On top of the convenience of automatically-starting and technically infinite operation time, permanently connected systems offer power output levels far higher than portables gas or diesel generators; the output rating of most permanent standby generators ranges anywhere from 5 kW up to 200 kW+. In the case of a long-term power outage, this makes them the ideal choice as complete home/utility backup generators, so long as cost is not an issue. These generators are far more expensive then portable gasoline or diesel generators and require professional installation, however, they do significantly increase the inherent value of a home. Portable Home Emergency Generators Portable Emergency Generators are far more common and easy to operate (those using Gasoline are more common than their Diesel counterparts). While they may not be automatic in nature, and they can only handle a small work load, considering the cost difference between other generators the portable emergency generators are probably the most economic option for average people. They usually range from 2kW to 100kW of power output and cost from $400 to $1,600. As in most average internal-combustion lawnmowers, portable gasoline or diesel generators require oil in addition to fuel. If you choose to go with this type of generator, it is recommended to have at least 1 quart of the correct weight/viscosity oil stored near the generator and stored fuel containers. Commercial Generators A huge step up from the standard portable gas or diesel generators, are commercial generators. In fact, Commercial Generators are the biggest around. These are often larger and more expensive even than the permanent home standby generators. Most are large, diesel engines and are frequently found as backup power for large commercial establishments (grocery, hardware, general, malls, etc.). Usually, they range from 2,000kW to 12,000kW of power and depending on size cost $5,000 to $500,000. They are generally not feasibly portable, and require a larger knowledge base (and toolbox) to maintain. However, if you own a large estate and want reliable full-property power, then this may be your best option. However, this, like the permanent home standby generator, is best left to the professional to install. Industrial Generators Industrial Generators have probably the largest amount of variation amongst the other generators. While most use diesel fuel, some are small and can easily fit in the back of a pickup truck or towed behind one (some are even built into vehicle-hitch trailer models). Some are the size of semi-trailers. Some are so large they must be built on site and can only be moved in pieces. Generally these generators can put out anywhere from 20kW to 2,000kW of power. Either way, for most people who want a lot of power out of a portable generator, there are plenty of options to choose from. They generally range in price from $1,000 to $10,000. I would only recommend choosing an Industrial Generator if you do not want something permanently installed in your house, such as a permanent home standby generator, but want portability and the capability to easily power every utility in your home. Personally, I would choose a portable home gasoline or diesel generator over a permanent standby, commercial or industrial generator. Mainly, in part, because the small internal-combustion engines they employ are far more common, easier to repair, portable, and simpler to maintain for the average person. If you can maintain a push lawnmower, you can easily maintain a gasoline or diesel generator. They are more than adequate in powering the bare essential utilities in your home (Heating system, Refrigerator, Water Pumps). Another benefit of gasoline or diesel generators to consider is fuel rotation. Fuel rotation means that if you have fuel stored, you should use it up before it reaches its stabilized shelf-life as listed on the commercial stabilizer. Fuel Rotation In fuel rotation, it is recommended to have at least two 5 or 6 gallon gas/diesel “Jerry”-cans filled and stabilized at any given time, separated by expiration dates of a year at a time. Example: John buys a gasoline generator and two 5 gallon Jerry-cans (properly colored bright red). He fills up both Jerry-cans with mid-grade octane and uses a commercial stabilizer. As they stand, they are good up to two years. After the first year, John completely uses one Jerry-Can in his lawnmower, and later that day while running errands he fills up the empty Jerry-can and adds the appropriate amount of stabilizer. Now this newly filled Jerry-can has a nominal shelf-life of around two years. Nine months later, he uses up the second Jerry-can, and refills and stabilizes it. He repeats this process, one year at a time, until he finds himself in a situation that requires the use of his generator. Once the need arises to use the generator, at any given time, he has two full 5-gallon jerry-cans that are good for at least one year. This method can be applied with any number of Jerry-cans. Just make sure you follow the fill-limit instructions on the Jerry-can and that you store them safely to avoid hazardous fuel-vapor buildup. If you choose to employ a diesel generator with properly preserved diesel fuel, the rotation process with two 5-gallon Jerry-cans (properly colored bright yellow) would be around 5 years. It is important to label your generators with the reoccurring month of rotation, or keep some sort of record of when the generator was last filled, in order to keep accurate rotation in effect. Accessories Just having a generator with plenty of the correct fuel and oil does not mean you are ready for a power outage. There are a few other additions that must be considered. First, if you are using a portable generator, are extension cords. Portable generators use internal combustion engines, and not only are fairly noisy, they have exhaust fumes that are better left outside. Extension Cords and Plug Adapters When selecting an Extension Cord, you must first determine what utilities you plan on connecting to the generator. Extension cords are fine for the smaller portable home generators because generally you can only plug in one to four appliances. Since the best way to use a portable home generator is to place it outdoors, it is ideal to run the extension cord[s] through an open window or door to the required utility appliances. Extension cords have a few significant drawbacks. Most common extension cords cannot be plugged into electric furnaces, some refrigerators, well pumps, or ceiling-light fixtures, due to different plug configurations. Also, if the cords are too long, the resulting power loss will likely damage the generator and connected appliances. If they are placed under rugs or carpets, a lot of heat can build up and become a serious fire hazard. If you plan on using a portable home generator, consider getting a Generator Cord (AKA Gen Cord). You plug the all-weather cord into your 20 or 30-amp generator outlet, and then run it indoors. The plug on the inside end splits into four 120V outlets, where you can plug in several household appliances or additional extension cords. If you have any devices with a different plug configuration or Voltage, you will probably require an AC-Adapter/Plug Layout adapter. Generally, some furnaces, refrigerators and well pumps may use different plug configurations other than the regular “dual vertical-flat slot above, one centered ground slot below” plug. Power Transfer Switches Power Transfer Switches redistribute power from a generator to the home’s circuit panel. It is highly recommended that they be installed only by a professional, licensed electrician. If installed improperly, any nearby utility workers servicing a power line can be electrocuted by your generator pumping power back into the grid. A power transfer system reduces the need for multiple extension cords running from the generator to individual appliances. A power transfer switch is installed beside the main electrical panel, and then it is connected to any circuits you want running during a power outage. When the power goes out, you start up the generator and run a single power cord from it to the transfer switch. Once you have the generator operating, you can choose the appliances and the corresponding circuits you want to use by toggling the respective switches. Most manual transfer switches include built-in wattage meters, which keep track of what is being powered. Without a built-in wattage meter, you can easily overload the electrical system, damaging your generator and powered appliances. Portable generators are usually measured by watts. Power transfer systems, on the other hand, are measured in amps. Basically, the larger the amps of a power transfer switch, the more electricity the power transfer system can handle. For example, a 50-amp power cord is a lot thicker than a 20-amp power cord, allowing it to handle larger wattage amounts. All you need to pay attention to here is what is listed on the plugs on generator. Everything else is a moot point. Find the highest-amp outlet that your generator has. If you have a 50-amp outlet, you will need to install a 50-amp power transfer system. If you have a 20-amp outlet on your generator then install a 20-amp power transfer system. Again, make certain you match the correct plug shape with the correct plug. Most modern portable generators have both household plug configurations (usually two to four of the 120V 3-prong plugs and at least one 120/240V 4-prong plug). They are designed this way to prevent electrical overloads or short-circuits. If it has three prongs, use a three-prong cord of the same layout; if four, use four. Most power transfer switches cost $200-$400, and will cost another $200-$400 to have installed. Power Inverters Almost all modern generators either generate directly to 120V or have built in power inverters in order to convert the 12V DC (direct current) produced by the engine into usable 120V AC (alternating current) required in most American homes. If you have an older generator without a built-on power inverter that only produces 12V DC, make certain you have the correct 12VDC-120VAC power inverter, or equivalent to match the requirements of your devices.