A generator can provide a reliable form of back-up power for your home in case of an outage. Purchasing the right generator requires careful consideration of the type and sizes available and your power needs. Always operate your generator safely, according to manufacturers instructions.
While your electric power is generally very reliable, outages do happen. Extended outages can be very inconvenient and uncomfortable, depending on the weather. Backup power is more than just a luxury for many homeowners. Those with security issues, or critical home medical equipment, have a serious need to maintain constant power. These issues—combined with the growing dependence on electronic gadgets of all kinds—have increased interest in emergency home generators. Many homeowners, however, are coming at this issue for the first time and often have little understanding of how home generators work and the different types that are available. This article is designed to serve as your guide in selecting the right system for your home. Types of Home Generators There are two basic types of home power generation systems available—portable emergency generators and standby generators. Portable generators are fueled by gasoline, diesel, or propane. Prices for residential portable units range from about $400 to $1,500, depending on size. Most units vary in size from 1 to 10 kilowatts (kW), although mid-sized sets at about 5 kW are the most popular choices. During a power outage, portable units are fueled, hooked to the load, and then started manually. Portable generators are easy to use, mobile, and useful for other purposes—like camping. However, they provide limited power and they must be refueled periodically. Standby units are mounted on a concrete pad outside the home, like an air-conditioning unit. The generator is connected to the home by an automatic transfer switch. Transfer switches prevent the generator from sending electricity back through the transmission line, keeping power line workers safe from harm. Within 30 seconds of a power failure, the generator starts the electric circuits in the home. When power is restored, the standby generator is automatically disconnected from the home circuits, and it powers down.
Standby units are typically fueled by natural gas. A major advantage of a standby unit is that it can be hooked directly to the natural gas line—with no need for fuel refills. Also, standby units turn on and off automatically—thus avoiding the need to manually start the unit. Standby units typically have a higher wattage rating than portable generators and—depending on size—can power all of the circuits in your home. Standby units are more expensive however—ranging from $2,000 and up—and must be installed by a qualified contractor.
Selecting the Right Size So, how do you choose the right size generator for your home? The answer depends on what you want to use it for. For powering some lights and a couple of appliances, a small portable unit would work. For long-term protection, including an air-conditioning unit, a standby unit would be the better choice. In sizing a portable unit, add up the total wattage of the equipment or appliances you wish to run. Check the owner’s manual or serial plate for wattage rating. Household items with motors—such as refrigerators or dishwashers—have a “start-up wattage” that is generally two or three times the running wattage. This must be calculated in the total. If no start-up wattage is listed, assume it is three times the running wattage. The table below provides average wattage ratings for typical household items. For standby systems, work with a qualified installer to properly size the system to fit your needs. Household Item | Running Wattage | Start-up Wattage | Refrigerator/Freezer | 700 W (0.7 kW) | 2,200 W (2.2 kW) | Microwave | 750 W (0.75 kW) | 0 | Clothes Washer | 1,100 W (1.1 kW) | 2,300 W (2.3 kW) | Television | 300 W (0.3 kW) | 0 |
Generator Safety If used properly, generators are a safe and effective means of providing power for your home in the event of an outage. Follow these tips to help protect your home and family: Do not attempt to connect your generator to the electrical system in your home or any building. The electricity you generate will back feed to the outside utility lines, where it can kill or injure utility service personnel attempting to restore power. A transfer switch—properly installed by a qualified electrician—can prevent the generator from sending electricity back through the transmission line. Make sure generators are properly wired for your home and do not connect a generator directly to your home’s main circuit panel. Never plug your generator into an outlet. Use properly sized and grounded extension cords, and keep cords hidden so they do not present a tripping hazard. Always properly ventilate a portable generator. Gasoline-powered generators produce carbon monoxide and the fumes can be deadly. Make sure that the total electric load on your generator will not exceed the generator’s rating. Handle fuel carefully. Turn the generator off to refuel. Store fuel in a properly designed container in a safe location, away from children. Make sure that a standby unit is installed by a qualified contractor according to National Electric Code and local building code standards.
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