The answer to 'what size generator do I need' is that the size of the generator you need will depend on the total wattage of the appliances and devices you want to power during an outage. As a general guideline, you'll want a generator that can provide at least 5,000 to 7,500 watts of power to run essential items like refrigerators, lights, and small appliances. For larger homes or if you need to power more energy-intensive devices, you may need a generator in the 10,000 to 15,000 watt range.
To determine the right size generator, make a list of all the items you want to power and add up their individual wattage requirements. This will give you a good estimate of the total wattage you need. Keep in mind that starting wattage (the power needed to initially start an appliance) is usually higher than running wattage, so you'll want to factor that in as well. It's also a good idea to choose a generator with a slightly higher wattage capacity than your total needs to have some extra headroom.