The answer to 'what size generator installation do I need' is that the size of the generator you need will depend on the power requirements of your home. As a general rule, you'll want a generator that can provide at least 25-30% more power than your home's peak electricity demand. This ensures the generator can handle the surge in power needed to start up large appliances like air conditioners or refrigerators.
To determine the right size, you'll need to calculate your home's total electrical load. This involves adding up the wattage of all the appliances, lights, and electronics you want to power during an outage. Once you have the total load, you can choose a generator that's rated for at least 25-30% more than that amount. It's also a good idea to consult with a licensed electrician who can help you select the right generator and handle the proper installation.