The size of the generator you need to run a house depends on the total wattage required to power your essential appliances and systems. Here’s how you can estimate it:
Step 1: Identify Essential Appliances
Make a list of essential appliances and systems you’d like to run during a power outage. Common examples include:
- Refrigerator: 600-800W
- Freezer: 500-700W
- Furnace fan or electric heater: 1,000-1,500W
- Air conditioning: 2,000-5,000W (depends on size)
- Lights: 60-300W (depending on the number of bulbs)
- Microwave: 600-1,200W
- Washing machine: 1,000-1,500W
- Sump pump: 750-1,500W
- TV and electronics: 300-600W
- Well pump: 1,000-2,000W
Step 2: Calculate Total Wattage
Add the wattages of all appliances you want to power. Remember that some appliances, like air conditioners and pumps, may require extra starting watts (surge watts) that are higher than their running wattage.
Step 3: Determine Generator Size
Generators are rated by kilowatts (kW), and 1 kilowatt = 1,000 watts. To convert the total wattage of your appliances to kilowatts, divide by 1,000. For example, if your total wattage is 6,000W, you would need a 6kW generator.
Common Generator Sizes for Homes:
- Small Home (Running Essentials): 5-7 kW generator
- Medium Home (Most Appliances): 7-10 kW generator
- Large Home (Air Conditioning, etc.): 10-15+ kW generator
Whole-House Generators
If you want to power the entire house, including HVAC, large appliances, and lights, you may need a generator in the 15-20 kW range or higher, depending on the home’s size and energy requirements.
It’s always a good idea to consult with a professional electrician to properly assess your energy needs and ensure the generator is sized correctly for safe operation.
