How Do You Size A Generator For Your House?

  • By: Umer.A
  • Date: January 6, 2022
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Generators are bought based on power output which is measured in watts. It all depends on the power required to deliver enough light and running appliances.

Generators are the prime source of offering you power during power outages. But for the maximum power supply, you need a properly sized generator that runs all appliances in your house.

They are ideal for keeping your houses warm during winters and cool during summers. Moreover, generators can help you with the storage of food within the refrigerators without any hassle.

So, to get your hands on the best size generator with the ultimate power supply, you need to have a look at the following buying guidelines:

How Often Do You Experience Power Outages?

Most people usually lose their power at least once or twice a year for about 3-4 hours, but it varies for other countries. The causes of power outages depend on external weather conditions, any breakage, or electric power problems. So, to keep yourself safe and sound, you can have a generator as the first defense.

If you experience severe power outages, consider a large inverter for portable generators.

If you rarely suffer from power outages, you can get a mid-sized or a recreational inverter.

When To Shop for A Generator?

People usually buy generators at the time of peak season when they are suffering from significant power outages. But the ideal time to buy generators is at the end of peak seasons because sellers usually offer ultimate discounts at such times.

What Generator Size Is Best for Your Home?

The consistency and power of the generator determine how much power will work for you. For instance, a generator having a capacity of around 5000 watts can cover the entire house.

First of all, start making a list of appliances you plan on running on your generator at times of power outage. For instance, if you run a refrigerator on a generator, it needs around 600 watts. Moreover, a pump needs about 750-1500 watts.

For an air conditioner, it needs around 2000 watts. It varies between 60-600 watts for lights, and for computers, it’s about 60-300 watts.

How Often Should I Start My Portable Generator

How Much Does It Cost You to Install A Generator?

The average cost of installing a generator is around $1411 to $7648. The generator model might cost you around $400- $9500, but the average price for installing a generator is about $4541.

You need home generators for electricity and heat restoration during a power outage in extreme weather situations.

For installing permanent home generators, the average cost is around $500-$3000. However, for portable generators, the cost is relatively minor.

Most of the generators are settled outside in a concrete area where they are fixed using permanent fixtures. And they need gas hookup or electrical wiring. Invest in a professional installation of generators.

What Devices and Appliances Do You Consider Essential?

When choosing the type of generator, it’s essential to consider which appliances you will run on it. Then mention the starting and running wattage of each appliance. Starting wattage of any device is more significant than running wattage. When the appliance keeps on running, it becomes stable. After which, you need to sum up the required wattage.

For considering the essential appliances, you need to identify the devices you’ll run on the generator. For example, the average wattage for virtual appliances in our house include:

  • Refrigerator: 150 to 400 watts.
  • Dishwasher: 1200 to 1400 watts.
  • Oven: 2100 watts.
  • Microwave: 900 to 1600 watts.
  • Coffee Maker: 800 to 1300 watts.
  • Central Air Conditioner: 1000 to 4000 watts.
  • Central Warming Furnace: 350 to 400 watts.
  • Window AC Unit: 1000 to 1400 watts.
  • Electric Fan Heater: 2000 to 3000 watts.
  • Dryer: 1000 to 4000 watts.
  • Washing Machine: 500 watts.
  • Laptop: 100-150 watts.
  • Flat-screen TV: 50 to 120 watts.

Every home needs a different amount of power for running the essential appliances. Still, most of the houses need an average of around 25kW generator for running the essential appliances at home. However, if you plan on powering the entire house, you need a generator with a power of around 35kW.

Does The Generator Size Fit Your Budget?

The essential thing to look for while buying the best-sized generator for a home is the budget. The great news regarding generators is, there is a massive range of options. If we talk generally, portable generators are comparatively cheaper than standby generators. Standby generators are a considerable investment. If you own a huge house and plan to run all appliances, you should consider standby generators.

If you have a great budget of around $10000, you can invest in a standby generator to power the entire house. However, if the budget is less and you plan to run only your home’s essentials, you can invest in portable generators. The portable generators can give you around 3000 watts. They are available for $400- $2000 or more, depending on the wattage.

However expensive, standby generators come at a price range of around $3000-$20000 based on the requirement.

How Much Power Do You Require to Operate The Home Appliances?

Generators come with different power outputs measured within watts. The generator that supports your need is the ultimate choice because you want to operate various home appliances using a generator at times of power outage.

For running essential home appliances, you need a generator having an average power output of around 5000 watts to 7000 watts. Make a list of appliances you plan on running over the generator. These include a refrigerator, freezer, air conditioner, space heater, lights, and much more. This helps you identify the breakdown of the wattage of your household appliances with power ratings.

If we generally talk about generators, standby generators are best with more power output than portable ones.

Can We Directly Attach the Appliance to The Generator?

If you don’t have enough budget to install a transfer switch, you can safely use heavy-duty cords to operate the essential appliances. You can use these cords for directly plugging appliances into generators. This helps you to power tools, computers, refrigerators, and more. Make sure the cord is heavy-duty and is thick enough for running the current.

What Type of Generator Is Best for The Home?

There are four types of generators available on the market, including standby generators permanently installed. There are inverters and portable generators in different sizes which you can move around.

Standby generators are best in times of emergencies. They offer the ultimate performance and work well for prolonged power outages.

Portable generators run on propane, diesel, or gas. Moreover, portable generators can run huge appliances like refrigerators or televisions. Portable power stations come with large batteries, which serve as a great backup in times of need. Some portable generators are powerful and can run air conditioners.

Inverter generators are small, and they convert AC power to DC power. They are small, quiet, convenient, and perfect for small devices and appliances.

Will A 12000-Watt Generator Run a House?

Yes, a 12000-watt generator is enough for running the entire house. You can run your appliances at once or partially. A 12000-watt generator offers enough electrical supply for running the whole house.

As we have listed the standard wattage required by the essential appliances, you can assess how a 12000-watt generator is enough for running the entire house.

Unless you live in a vast mansion, you might need to opt for a generator with an extra power supply.


Seek professional help to get the correct estimate of the power supply. If you choose a small generator, the essential appliances won’t work correctly during power outages. Overloading your generator can result in a short life of the generator. It can also affect the life of your appliances and impact adversely.

We hope this guide have helped you in choosing the right size generator for your house!