Homeowners can often power most household appliances using between 3000 and 6500 watts.
If your home has a small furnace and you are on city water, you can probably get by with a 3000 to the 5000-watt generator. If you have a large furnace and/or a water pump, you will likely need a 5000 to a 6500-watt generator (Honda).
If you plan to power just lights, fans or computers or a small camper then a 1000-2000 watt generator would be ideal. You have to determine your need before purchasing one, but even before that determine if you need or want one at all.
Appliances usually note their power requirements in amps while generators list their output in watts. It’s easy to convert from one to the other, however.
Watts = Volts x Amps
Amps = Watts/Volts
Starting vs. Running Wattage
Certain appliances require extra power to start up, while on the other hand others maintain the same power requirements continually.
To calculate the size generator you need, you will need to determine the load. (A load is defined as the device that you are powering.) There are two kinds.
Resistive loads require the same amount of power to both start and run the equipment. A few examples of resistive loads include:
Reactive loads will have an electric motor, which requires added power to start, in other words, higher watts to start and then reduced wattage to run. You need the higher watts to essentially kick-start the motor. Normally the starting power is 3 times the amount of power needed to run the application. A few examples of reactive loads include:
It will take you putting pencil to paper to determine the size generator needed. Things you need to consider include portability, what happens if you have to leave your home, can you take the generator with you, will it fit in the car and fuel requirements, storage, and transportation of the fuel.
Most home use generators would easily fit in the back of a pickup or some SUV’s, but you would have to make sure you left enough room after packing your other supplies. The smaller generators may fit in the trunk of some cars.
Your larger generators will have 120 and 240-volt receptacles for direct plug in, but you can’t drag your dryer or water pump out to the backyard and plug it in so you do need the proper cords. If you are planning on powering up large appliances and are using a 5000-watt or higher generator then a power transfer system is recommended. It is also recommended that you have a qualified technician install this system.
What the system does is allows you to keep your appliances plugged into their normal receptacles. The transfer system connects to your breaker box. The system is then plugged into your generator when the time comes and power from the generator is routed through your home’s system to power certain appliances. The generator may not run your entire home, but will allow you to operate refrigerators/freezers, lights, radios and possibly your heat/cool system and water pumps. You may not be able to run all appliances/devices at the same time, however.
If you plan to just run cords to certain appliance directly from the generator make sure the cords are rated for the appliance and are rated for generator use.
Do you need a generator, almost anyone could benefit from one. A 1000-watt generator could run lights, emergency radios, and be used to charge up electronic devices such as cell phones, computers, Two-Way radios, and operate small power tools, and so forth.
Even if you live in an apartment building, you could take the generator with you if you can evacuate with a vehicle. Carrying one along with fuel without a vehicle would be out of the question. You could set one up in any outside location, keeping in mind, however; there is the noise factor if you are in stealth mode.
Those that live in a standalone dwelling would benefit from any sized generator. You can run refrigerators, freezers, heat, and cooling systems, water pumps, lights and so on, if you have the properly sized generator.
You, of course, would eventually run out of fuel if the distribution hubs are down, but with some rationing of fuel, you can maintain one for an extended period if you prioritize your needs.
Honda. (n.d.). Retrieved 2016, from http://powerequipment.honda.com/generators/generator-how-much-power