How to Select the Right Size for Your Backup Generator

Among the most important decisions that need to be made when buying a backup generator for your home is what size you’ll be purchasing. The size of your home and the energy consumption of your appliances will determine which generator size is right for you.

If a backup generator is too big for your home, it will cost more than necessary to run. Using a generator that’s too small will result in you being unable to obtain the amount of energy needed when the power goes out. At Comfort All-Stars, we can help you identify which generator size is suitable for your home in the Tampa Bay Area.

Understanding the Terminology

The power that your generator needs to create depends on the systems that you want to operate. Before you make any final calculations that will help you choose the right size for your backup generator, you should know what running wattage, starting wattage, and surge wattage mean.

A system’s starting wattage refers to the total electricity that it requires to start up. When a device first turns on, it uses a large amount of electricity to do so. The average amount of power that’s required to start an appliance is typically three times higher than the amount needed to run it. Surge wattage refers to the highest amount of power that you can get out of your generator.

You should protect the generator of your choice with a circuit breaker. Without this precaution, you might eventually encounter problems with overheating and overloading. If you don’t shut off the generator once it overheats, a fire could break out.

How Much Power Do You Require?

If you’re trying to select the right size for your backup generator, you should first identify how much power is required for you to run your entire home from this device. Your equipment manuals should provide you with specific wattage numbers that will make it easier for you to calculate your power consumption.

In the event that an appliance is equipped with a motor, the total wattage that the appliance needs can be calculated with the following formula:

Running wattage (R) + Starting wattage (R x 3) = Total wattage required

With this formula in mind, you should be able to determine the wattage demands of all appliances with a motor. Coffeemakers and light bulbs don’t need additional power to turn on at the start, so their running wattage is all you have to know. Larger generators are often needed for homes that contain numerous appliances.

Power Needs for Home Appliances

Each type of household appliance has a different running wattage. The running wattage figures for the most common home appliances are listed below.

  • Coffeemaker: 400 to 800
  • Electric oven: 5,000
  • Hot plate: 1,250
  • Toaster: 1,100 to 1,700
  • Microwave: 1,200
  • Refrigerator/freezer: 600 to 800
  • Vacuum cleaner: 700 to 1,400
  • Hair dryer: 1,200 to 1,500
  • Personal computer: 500 to 2,000
  • Space heater: 1,250
  • Table lamp: 150
  • Television: 100 to 350
  • Water heater: 3,000 to 4,500

Power Needs for HVAC Systems

Here are some estimates of the wattage requirements for the various types of HVAC system you might have in your home. The total wattage for some of these appliances depends on the size and type of unit you’ve selected for your residence. Less efficient appliances typically use more power and have higher wattage needs.

  • Central air conditioner: 2,000 to 4,000
  • Window air conditioner: 600 to 1,500
  • Electric furnace: 5,000 to 25,000
  • Radiant heater: 1,300

The wattage requirements listed above are examples and ranges that should be fairly accurate. However, the specific wattage of your appliances require should be listed in the user manuals that you received when you first purchased the equipment.

How to Calculate Generator Size

The owner’s manual that comes with a backup generator will typically include the types of devices and structures that it’s capable of powering. However, you can also choose to make these calculations yourself, which should help you identify the best size of generator for your needs.

Let’s say that you want to have a generator installed in your home to power a relatively small refrigerator. In the refrigerator manual, you might find that the appliance’s running wattage is around 350 watts. You could use this information to determine that the starting wattage will be three times higher than the running wattage for a total of 1,050 watts.

The total wattage consumed by the refrigerator would then be 1,400 watts, which means that the backup generator you select should be powerful enough to provide 1,400 watts of energy. However, the backup generator size you select should easily surpass your power needs, which means it should be able to handle more than 1,400 watts. You shouldn’t use more than 90% of the generator’s capacity when it’s turned on.

Types of Generators to Consider

There are several types of generators available to you, each of which comes in different sizes. Most of these systems operate using diesel, natural gas, or propane as fuel. The three types of generators at your disposal include portable generators, whole-house generators, and inverter generators.

Portable Generators

Portable generators have enough power to provide you with electricity for tailgating, camping, and other outdoor activities. You can take these units to any destination without adding much weight to your vehicle. Portable generators weigh anywhere from 50 to 250 pounds and accommodate around 3,000 to 15,000 watts.

You should never use this type of generator inside a closed structure, including a garage. It’s not safe to do so even with doors and windows left open. Carbon monoxide could build up. It’s undetectable, and it can be fatal.

Whole-House Generators

A whole-house generator gives you a backup for your entire residence in the event of a storm or blackout. These systems are hardwired directly to your home and should quickly deliver power if your primary source of energy goes down. The generator transfer switches that these systems come with can either be manual or automatic. This type of generator can accommodate anywhere from 7,000 to 150,000 watts of power.

Inverter Generators

Just like other types of generators, inverter generators provide electricity. However, they do so with more fuel efficiency and less noise. They can also convert AC power over to DC power, which allows them to be used for battery-powered appliances and RVs. These generators typically support anywhere from 1,500 to 10,000 watts.

If you need additional assistance when searching for the right size of backup generator, reach out to us at Comfort All-Stars. Once you’ve made your final purchase decision, we can install your backup generator and show you how to use it. We offer a wide range of residential services to homeowners in or near Tampa, FL. If your heating or cooling system isn’t properly altering your home’s indoor air temperature, we’ll diagnose the problem and provide the necessary repairs. Full maintenance and installation services are also available.

The electrical services we offer include everything from LED lighting upgrades to electrical maintenance and repair. We can also provide your home with surge protection. Some of the additional options we furnish include duct cleaning, duct sealing, and indoor air quality services. We can install any type of filtration system into your home to reduce contaminant levels and keep your air fresh. Call Comfort All-Stars today to ask about our specials or schedule our services.

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