free shipping icon US Local Warehouse, Free Shipping! US Local Warehouse, Free Shipping!
30-Days Return icon 30-Days Return 30-Days Return
Select Your Country/Region

What Size Backup Generator Do I Need for My Home?

Facebook icon Twitter icon Twitter icon Email icon

Imagine a stormy night with lightning flashing and thunder rolling, when suddenly the power goes out, plunging your home into darkness. A power outage can cause various inconveniences, from simple nuisances like being unable to charge your phone to more significant disruptions like spoiling food and losing heating capabilities.

In this article, we will help you determine the perfect size for a backup generator to ensure that your home is always prepared for power outages. No more worries about being left in the dark!

backup generator - Growatt

The Need for Backup Generators in Homes

The average American has to deal with their lights going out around 8 times a year according to some study from the U. S.  Energy Administration, and that's double what it was in 2013. We're having way more blackouts now for some reason. Experts say climate change and old power lines are why it's happening more.

Power outages lead to a number of problems, like all the food in your fridge going bad. If it's winter, your pipes could freeze up which can lead to water leaking everywhere as soon as the heat comes back on.  

The best way to avoid these problems is to get a backup generator. It kicks in when the power goes out so you can keep your appliances running. That way, you don’t end up with a huge mess whenever there's a blackout.

Determining Your Power Requirements For A Backup Generator

First off, you have to figure out how much power you really need.  It's like going to the grocery store - you wouldn't know what to buy unless you know what you're going to cook.

So here's what you need to do to calculate your total power consumption:

Calculate Total Power Consumption:

1. Identify Essential Appliances and Devices

Make a list of all the appliances you absolutely cannot live without if the power goes out. This will include fridge, light medical equipment, your home office gear - all the essentials.

2. Determine Their Power Ratings (Wattage)

Next, you need to dig into the nitty gritty technical jargon and check the wattage of each appliance. This info is usually on the product itself or in the manual. Add up all the wattage numbers to get an estimate of the minimum amount of power your generator needs.  

3. Account for Starting Surge

Some appliances like ACs, fridges, and sump pumps need a surge of extra power when you first turn them on before they settle into a normal running wattage. So, you will need to account for that startup surge, too, when figuring out the total wattage needed.

Surge Factor and Its Impact

When picking a generator, the surge factor is very important to think about. That's because it can easily be two or three times higher than the normal running watts that the appliance needs. For example, take a refrigerator that runs on 700 watts normally. When it first turns on and starts up, it'll need a surge of 2200 watts! So, if you want to make sure your fridge and other appliances start up smoothly without issues, you need to get a generator that can handle those startup power surges.


Starting Watts

Running Watts




Air Conditioner (10,000 BTU)






Microwave (1000W)



Electric Stove



Washing Machine






Sump Pump (1/2 HP)



Furnace Fan (1/2 HP)



Television (LED)



Coffee Maker



Hair Dryer



Electric Grill



home backup generator - Growatt

What Types of Backup Generator Should I Choose?

Now that you've got your power needs sorted, let's look at the different types of generators available. Think of this as choosing the cuisine after you've decided you're hungry.

1. Fuel Generator

Fuel generators are the traditional, most common types you'll find. They run on various types of fuel such as diesel, gasoline, or propane. They're generally powerful and can run most household appliances. However, they can be noisy and emit fumes, so proper ventilation is essential.


  • High Power Output: Capable of powering multiple large appliances and tools.
  • Versatility: Available in various fuel options like gasoline, diesel, and propane.


  • Noise Pollution
  • Fuel Storage
  • Green-house Emissions
  • Maintenance

2. Solar Generator

For those who prioritize environmental sustainability, a solar generator presents an ideal option. These generators operate silently and have a low environmental impact, although they typically offer less power compared to fuel-powered options. They are well-suited for powering smaller appliances and are particularly advantageous during daylight hours when sunlight is readily available.


  • Eco-Friendly
  • Low Maintenance
  • Silent Operation


  • Limited Power Output
  • Dependency on Weather
  • High Initial Cost

3. Inverter Generator

Inverter generators are like the tech-savvy younger siblings of fuel generators. They offer several advantages over traditional generators, such as quieter operation, increased efficiency, and cleaner electricity output. This makes them perfect for powering sensitive electronic devices like laptops and smartphones that require stable power supply. The inverter generators are particularly well-suited for modern electronics.


  • Quiet Operation
  • Clean Power


  • Limited Power: Not suitable for powering large appliances or multiple heavy-duty tools simultaneously.
  • Higher Initial Cost: Generally more expensive upfront compared to traditional generators.

4. Whole House Generator

If you're searching for a reliable backup power solution, a whole house generator is the perfect choice. These generators are installed outside your home and activate automatically during a power outage. They have the capability to power all of your essential appliances, from your HVAC system to even small devices like electric toothbrushes.


  • Convenience: The system will automatically activate during a power outage, eliminating the need for any manual intervention.
  • High Power Output:has the ability to provide electricity for your entire home, including multiple large appliances and systems.
  • Long-Lasting:Designed with a long lifespan, reducing the need for frequent replacement and minimizing its environmental footprint.


  • High Initial Cost:Both the installation process and the actual generator can be quite expensive
  • Fuel Consumption: These engines usually operate on natural gas or propane, which can produce greenhouse gas emissions.
  • Space Requirement:Setting up this system will require a specific area separate from your home.
  • Maintenance:Similar to other fuel generators, regular maintenance is required for proper functioning. This maintenance process may produce waste and potential environmental hazards from used oil and filters.

Making sure your house keeps running even when the power goes out means you need to figure out how much power you need and the types of generators out there.  This way, you can pick the one that really works for you.  

Why Should You Have the Right Size Generator?

The right size generator isn't just about what's convenient - it also keeps things running safely and reliably.  The generator size will make a big difference in how well a generator performs, how reliable it is, and how safe it is to use.

1. Performance

Choosing the right backup generator size is key to maximizing efficiency and performance. An oversized generator can lead to inefficient power production and unnecessary costs. Conversely, an undersized generator may not be able to meet your home's power needs, leading to frequent shutdowns or potential damage. Proper sizing ensures that the generator can handle the starting and running wattage of all the appliances you intend to power, promoting smooth operation

2. Reliability

Having the right sized generator is important for making sure things keep working even if the power goes out. If your generator isn't big enough, it cannot deliver an efficient power supply. Appliances like medical equipment, fridges and furnaces need a steady power supply to work properly. An undersized generator that can't provide enough power all the time, and this is going to lead to issues.

3. Safety

Safety has to come first and don't compromise when it comes to picking a generator size.  An oversized generator could totally damage your electrical system. It is important that you follow the generator sizing guidelines from the National Electrical Code and National Fire Protection Association.

Other Ways to Know What Size Backup Generator You Need

If you're not certain about the appropriate size for your backup generator, there are other methods to help determine your requirements:

1. Consult a Generator Expert

Picking the perfect generator for your home can be tricky.  There are so many options to weigh - fuel type, output power, noise level; where do you even start? It is good that you talk to an expert to help match you with the right model.

2. Consult and Hire an Electrician for an On-Site Assessment

An electrician can help you check out your electrical system at home.  They can calculate your electrical load based on hardwired appliances like your AC, well pump, etc.  That way, you can get a generator powerful enough to keep those critical systems running if the power goes out.  An electrician will make sure you get a generator tailored to your home's electrical demands, not just a one-size-fits-all option.

3. Use Calculators from Electricity Websites

There are several websites that have free generator size calculators.  They ask you questions like how big your house is, the number of appliances that you have, and other factors to tell you the right generator size that you need.  


1. Can I Run My Whole House on a Portable Generator?

Although it is technically feasible to power your entire house with a portable generator, it may not be the most practical solution for extended periods. Portable generators are typically designed for temporary use and may lack the capacity to simultaneously power all of your home's appliances and systems. Additionally, you will need to account for fuel storage and frequent refueling. For long-term, whole-house power, a standby generator is a more suitable option.

2. What Size Generator Do I Need to Run a 2000 sq ft House?

The size of the generator you need for your house is not solely determined by the square footage. It depends on the total wattage of the appliances and systems you want to power. To find the right size, make a list of all essential appliances and their wattages, add them up, and consider any starting surges. Typically, a 10,000 to 20,000-watt generator is suitable for a 2000 sq ft house, but individual requirements may differ.

What Size Generator Do I Need to Run a 2000 sq ft House

Final Thoughts

Choosing the appropriate backup generator for your home is an important choice that demands thorough planning and thoughtfulness. It's crucial to assess your power requirements and carefully consider the advantages and disadvantages of various generator types. Key factors such as safety, performance, and reliability should serve as guiding principles when making your decision. With the information provided in this article, you now have a better grasp of what it takes to make an educated choice that aligns with your specific needs.

Solar power is a good option if you need moderate power needs, and care about the environment. Solar generators use the sun's energy, so they don't release greenhouse gases like other kinds of generators.  They work well for lighting, fans, charging phones and small electronics. You can feel good about using one because solar power is sustainable and reduces your carbon footprint.

Growatt INFINITY 1300
Growatt INFINITY 1300 LiFePO4 Portable Power Station
  • 1382Wh Capacity & 1800W Output
  • LiFePO4 Battery with 3,000+ Life Cycles to 80%
  • Fully charged in 1.8 hours
  • Up to 14 Versatile Outlets
$1,099.00 $1,299.00
Get Discount Now