The amount of power your generator can produce is measured in watts (or kilowatts) and is called wattage.

The wattage you need depends on the size of your house and how many appliances and devices you need to run during a power outage. To get a rough estimate of the wattage you will need, list all the appliances and devices you want to run during a power outage. Then list the power requirements (in watts) for each item. And finally, add up all the power requirements to get the total wattage. 

This can be complicated. You might need to convert some of the items’ power needs into watts. Plus you will need to take into consideration the starting and running wattage of each item. When turned on most devices need more power (starting wattage) before dropping down to its running wattage. 

The above will give you a rough idea but you really should get a more accurate estimate. The best way to get an accurate estimate is to consult with your electrician. 

Try and get as accurate an estimate as possible. The wrong-sized generator could lead to damaged appliances and devices and unreliable power. A generator that is too small won’t provide enough electricity for your needs and will be prone to overheating and overloading. If you get a generator with more wattage than you need you are paying for capacity you will never use. Plus an oversized generator has the habit of tripping its own breaker.