Electrical Inventory

• 1
  List all appliancesmicro wave oven image by mattmatt73 from Fotolia.com
  
  Make a list of all the systems and appliances in your home that you want to use during a power outage. Start with the major systems that affect your entire house: heating, air conditioning, well pumps, sump pumps, security systems, etc.
  
  
• 2). Walk through each room in your house and add to the list the appliances you find. Start in the kitchen, which contains many of the major appliances: refrigerators, freezers, ovens and electric ranges. Add any small appliances: televisions, radios, small kitchen appliances, hair dryers, etc., that you will want to use in each room.
  
  
• 3
  Identify lighting requirementsnight lamp / bed lamp image by Sid Viswakumar from Fotolia.com
  
  Estimate the lighting requirements of each room you will be using during an outage. You can either note the number of lamps or ceiling fixtures and their size in watts, or approximate the requirements by estimating the square footage of the room.
  
  

Determine Power Needs

• 1
  Calculate wattagecalculator image by L. Shat from Fotolia.com
  
  Estimate the power requirements, in watts, of each item on your list. Examine the manufacturer's label on each item, which will indicate how much electrical power it consumes. In some cases, the figure will be given in amperes, or amps. Convert amps to watts by multiplying the amps by the voltage of the electrical circuit the device uses. For example, if a hair dryer's label says it uses 10 amps, and it plugs into a normal 110 volt electrical outlet, it consumes 10 X 110, or 1100 watts.
  
  
• 2). Estimate lighting needs for each room using a rule-of-thumb figure of 1 watt per square foot: A 10-by-10-foot room can be adequately lit by a 100 watt bulb. This is only necessary if you have not noted the actual size of each room's lights.
  
  
• 3). Estimate the starting requirements for each of the items on your list. Devices with compressors or other electric motors require a surge of power at the instant they start, often far higher than the power level they need under normal operation. A refrigerator that consumes 600 watts, for example, may use 1200 watts momentarily when the compressor starts. Many generator manufacturers' websites describe these requirements for a number of items.
  
  
• 4). Select the single item with the greatest starting power requirement. Since it is unlikely that multiple devices will be starting at the same instant, use this single item to determine the generator's peak power requirement.
  
  

Determine Generator Size

• 1). Add up all the power requirements for the items on your list, giving you the minimum size for your standby generator. Manufacturers recommend adding a 10-to-20-percent cushion to that figure to ensure your generator has sufficient capacity. For example, if your power requirements add up to 6000 watts, the proper generator will have a capacity of 6600 to 7200 watts.
  
  
• 2). Add the start-up wattage requirement. This identifies the peak capacity your generator must have. For example, if you have determined that your sump pump demands an additional 1000 watts during start up, add that to the generator size you calculated.
  
  
• 3). Start shopping for a generator of the appropriate size. If you find that you are exceeding your budget, you can go back through your list and determine if there are any items you can do without during an outage. Remove them from the list and recalculate your requirements.