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Backup generators come in a huge range of sizes, from 9 to 22 kilowatts of power. How big of a back-up generator do you need for your home? You don’t want to choose a generator that’s too big because it will be more costly to run it, and you won’t be able to keep it going for as long with the same amount of fuel. Undershooting your generator size is even worse, because you may not be able to run what you want to. Let’s discuss what you need to know to get the exact right size backup generator for your home.

Do You Want to Power the Whole Home or Selected Items?

First you need to decide how much of your home you’d like to power during a power outage. Most people end up choosing to power their whole home. After all, the point of having a generator is to live your life uninterrupted when a power outage happens. Though, you may choose to just run the essential parts of your home, such as your refrigerator, air conditioner, and well pump.

Understand Starting vs. Running Wattage

Once you’ve decided which appliances you want to run, you need to add up the wattage that each appliance uses to discover the total your standby generator needs to produce. You will need to know the running wattage for which your appliances are rated. However, if you plan on turning appliances off and on, you will also need to know their starting wattage.

Many appliances use a surge of energy when they first startup. If you don’t plan for this, you may be unable to turn the appliance on when you need to. If you’re getting a standby generator installed, you don’t need to worry about this as much because they will kick in right as power goes out. That means you shouldn’t need to turn on appliances.

Although, if you typically turn some appliances on and off (such as an air conditioner) you should make sure you have enough power to do that. Don’t make the mistake of thinking that you need to turn all of your appliances on and off at the same time. Just plan enough excess power to turn on the appliance that uses the most upon startup. Then be careful to only turn one on at a time when the generator is running.

Calculate Your Home’s Usage

You now need to figure out how much each of your appliances will use when starting up and when running. Each should be rated, and you do want to get their specific information instead of relying on estimates on the internet. They work on averages, but you never know if your microwave or fridge uses much more or less energy than average. Those estimates can be useful to make sure you’re in the right ballpark, but they’re no guarantee.

Consult the Experts

A standby generator is an important investment. The last thing you want is for your generator to fail when the power goes out. Ask your HVAC professional to look over your estimate and make sure that you’ve included everything you need to. They may have advice about which size or type of generator would be a better fit for your needs.