To determine which generator is right for your needs, you must first add up the wattage of tools,
appliances and motors you want to run at the same time. Then select a generator with the RUNNING
wattage rating to match or exceed the total load. Keep in mind that tools and appliances with
electric motors require additional tool/appliance SURGE wattage at startup that can be double or
triple the normal running wattage requirement. Look at the surge watts required and make sure you
choose a generator with enough additional wattage to start them. Keep in mind that you typically
are not starting more than half of the items at the same time.
Generators are rated by output in wattage which takes into account the amperage at both 120 and 240 volts. NOTE: Volts x Amps = Watts (i.e.: 120 volts x 10 amps = 1200 watts) OR Watts/Volts = Amps. For example, a 5000 watt rated generator is capable of producing 20.8 Amps @ 240 Volts or 41.6 amps @ 120 volts. See the following chart for power ratings for common household appliances.
|ITEM||RUNNING WATTS||SURGE WATTS|
|Furnace Fan (gas or oil only) 1/8 HP||300||500|
|Well Pump||1/3 HP||750||1400|
|Sump Pump||1/3 HP||800||1300|
|Garage Door Opener||1/4 HP||550||1100|
|These are only estimated wattages, Please check your particular appliance for actual wattage.|