What Size Generator Do I Need to Power My House?

Gasoline generators are available for homes as a backup power source when power outages occur.

Determing Your Needs

Most generators for the home are small and portable for short periods of use and easy storage. The size of the generator needed will depend on the size of the house and the needs of the occupant. .

The first step in determining your generator needs is to look around the home to see what essential appliances will be needed if the power goes out. Many people want to be able to put the furnace or air conditioner on the top of the list. This will require a larger generator and one that will also be able to handle both 120 and 240 volts.

Other essential appliances that should be considered when choosing the size of the generator include refrigerators, microwaves and television or radio. The appliances chosen should provide only what you need to get through a power outage.


Before looking at different sizes of generators, determine the output of the essential appliances you chose. You will need to calculate the wattage requirements for each appliance. If the wattage is not listed in the owner's manual or on the appliance itself, you can determine the wattage from the amps and volts it requires. Use amps x volts = watts.

Once all of the calculations are complete, add the total wattage of the appliances to together. This will give you a rough estimate of the wattage you need with your generator. Add 10 percent to the total if you want to make sure there will be enough power available from the generator.

Types Available

Generators for the home are available in sizes ranging from 1,000 watts to 12,000 watts. Use the total wattage calculated earlier to determine what generator will fit your needs. Buying a generator that is too small can overload and cause damage to the generator or the electrical system of the house. Generators that are too large will waste power and money with fuel costs.

Another choice homeowners have is the type of fuel the generator takes. Natural gas, gasoline and diesel generators are available. Diesel generators are typically made for commercial use and not recommended for a small home. Natural gas generators are more expensive than gasoline generators, but the natural gas type can burn cleaner and provide longer storage capabilities than gasoline.

About the Author

Terri Deno is a freelance writer living near Indianapolis. She holds a B.A. in English from Ball State University. She has a passion for research; this passion is the driving force for writing about antiques, literature, genealogy, shopping and travel.