Selecting the Right Size Generator

Selecting the right size backup generator to meet your needs involves two steps:

  1. Deciding what you will backup
  2. Determining the electrical demand of the items you will be backing up

Backup what is
important to you!

Deciding What to Backup

When you select a backup generator, you can decide what is most important to backup. For example, heat may be critical in a cold climate. In contrast, central air conditioning may be considered a luxury that you can live without for a few days in the event of a blackout. The items most often considered critical are:

  • heat
  • well pumps if you rely on well water
  • sump pumps
  • lighting and small appliances, such as TV, computers, and kitchen appliances
  • refrigerators and freezers
  • small air conditioning units (window air conditioners)

The electrical items most often excluded from backup power are electric stoves, washers/dryer units, and central air conditioning. These are items that demand a lot of electricity, and they are items that one can usually live without for a few days with only minor inconvenience. Nevertheless, you may consider these heavy users of electricity critical to your comfort and security and may wish to include them in your backup plans.

Determining Electrical Demand

Once you decide what you want to backup, you need to make a list of everything that will be backed up. Generac Power Corporation, which makes the Guardian line of home backup units that we sell, created an interactive device to help you decide how much backup power you need.

Backup Needs Worksheet

You actually backup circuits of your home, defined by individual lines with a circuit breaker. Major appliances, such as stoves, furnaces, washer/dryers, and central air conditioning are likely to have their own circuit. Other items may not have their own circuit, but rather will be on a circuit that powers a room or a portion of the house. In most cases, you will be backing up everything except for a few specific circuits that require very large amounts of electricity (e.g., central air, electric stove, etc.).