This handy worksheet will help you make generator sizing a simple process. You’ll need to write your answers down in order to properly calculate your power requirements.
Most light bulbs and modern appliances and devices have their wattage demands marked clearly on the device. In the event, you don’t see this vital information, refer to your owner’s manual. If that’s not available, you can contact the manufacturer. As a last resort you can acquire this information from a qualified generator reseller or dealer.
Remember this formula: Amps x Volts = Watts
Do You Want Your Generator To Power All Or Part of Your Home, Office or Building?
(Note: for emergency use, you don’t need to size the generator to power everything; only the devices that will help you survive and be comfortable)
What Appliances, Devices and Tools Do You Want To Run and Why?
(Make a list of all of the appliances, etc., that you will be powering by your generator. Ask yourself the question, “why,” to help you determine if you really need that appliance, room or device during an emergency or power outage)
Do You Have Any Devices Such as Motor or Pumps That Require 240 Volts?
(If so, you will need a dual output 120 and 240 Volt Generator. Don’t assume all devices are 120 volts, check and confirm)
What is the Starting Wattage For Each Appliance, Device and Tool?
(This figure is the one you will use to determine your actual generator size)
What is the Running Wattage For Each Appliance, Device and Tool?
(You will use this figure if you have no devices such as motors or pumps that require a higher wattage at start up)
What is Your Total Wattage?
(You take your total start up wattage and add 20 to 25% and that figure is your total wattage)
Remember to consult a licensed electrician and/or a qualified generator specialist if you are unsure of these calculations. As we have repeatedly stated, generator sizing is the most important facet of choosing a generator. Get this process wrong and you will most likely experience one or more of the symptoms people are faced with when they miscalculate their power needs.