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Generator Selection - How Much Power Do You Need?

One of the most frequently asked questions we get is “How big of a generator do I need?” What you really need to know is how much power or total wattage you will need. This will depend on the types of equipment you want to run during an outage. But, before we get into that, let’s discuss the different types of wattage - starting wattage, running wattage and surge wattage. 


Running wattage is just as it sounds - the wattage required to keep an item running. Items with a motor require more wattage to start - this is the starting wattage, and in some cases can be three times the running wattage. Surge wattage is the maximum power you can get from your generator. 

We’ve compiled a list of household items with average running wattage below that you may want to power during an outage. To determine the best generator for your needs, add all of the wattage numbers together for the items you’ll want to power. This will give you an approximate potential running wattage. Don’t forget to add starting wattage for items with a motor. If you prefer an exact number, gather your owners manuals - they’ll have exact wattage numbers.

Approximate appliance/technology wattage needs:

  • Refrigerator/Freezer: 600-800 
  • Electric Range (one element): 2500 
  • Toaster: 1100 -1700 
  • Microwave: 1200 
  • Hot Plate: 1250 
  • Coffeemaker: 400-800 
  • Electric Oven: 5,000 
  • Television: 100-350 
  • Personal Computer: 500-2000 
  • Hair Dryer: 1200-1500 
  • Vacuum: 700-1400 
  • Space Heater: 1250 
  • Table Lamp: 150 

Approximate HVAC/system wattage needs:

  • Electric Furnace: 5000-25000 
  • Heater (radiant): 1300 
  • Central Air Conditioning: 2000-4000 
  • Water Heater: 3000-4500 
  • Water Pump: 1000-2000 
  • Window Air Conditioner: 600-1500 
  • Outdoor Lighting: 500-1000 
  • Sump Pump: 1500

Next, you’ll need to determine the type of generator that will work best for you. 

Generators can be fueled by various sources - solar, battery, propane, natural gas and diesel fuels. The three types of generators are: Portable, Inverter and Stand-by/Whole Home Generators.  

  • Portable generators are relatively affordable and convenient to take with you, wherever you go. They are powerful enough to power most of your outdoor activities - tailgating, camping, etc. and are perfect for powering you up during a storm or blackout. 
  • Inverter generators are great if you’re looking for a quieter, more fuel efficient generator. They convert AC power to DC, so they work well for RV use and powering up your battery operated devices. 
  • Home Backup or Stand-by Generators are hardwired to your home’s power and will keep you up and running in a storm or blackout. When the grid goes down, your stand-by generator quickly brings you back up very quickly. You’ll need a qualified electrician to install a transfer switch and a circuit breaker. 

Safety First!  Never use your generator inside your garage, home or any other structure, even with the windows or doors open. Carbon monoxide is a very dangerous gas that is virtually undetectable.