How Big of an Emergency Generator Do I Need? – A Helpful Guide!

You never know when the power will suddenly go out. A strong gust of wind, a wildfire or other natural disaster can take out power lines like they are toothpicks. You will need an emergency generator to fit all your needs and make getting through the storm as comfortable and easy as possible.

When determining how big of an emergency generator you will need to consider your power needs, budget and how frequent you experience power outages.  The more comforts you need, like hot water and air conditioning, will require a bigger generator versus someone who just needs to plug in a fridge and coffee maker.  Your budget will also determine how big of a generator you need.  The bigger the generator the more expensive.

Power Needs

Home Power Needs
Emergency Power Needs

Have you ever wondered how much power you use every day? It typically doesn’t become apparent until the power goes out and you realize how many items in your home require power. If you enjoy a nice hot shower in the morning to wake you up and get ready for the day, you need hot water.

Hot water is there when you need it thanks to your hot water heater. That hot water heater uses power to create heat and make your morning shower so enjoyable.  If you need a cup of joe to get motivated and moving in the morning, you need to plug in your coffee maker. Most coffee makers require power unless you are using a French press.

Most of us have come to expect power to be there when we need it- when it’s not there, your world may suddenly feel like it’s falling apart. This is why so many homeowners invest in generators to make sure they can keep a few lights on, heat circulating and make sure the food doesn’t spoil.  All these modern-day conveniences take power- and all the watts add up fast. This is where you need to make a few tough decisions.

In most cases, you will not be operating your home like you would if the power was on. Let’s just get that notion out of the way. Of course, if you have thousands of dollars to invest in a standby generator, you may not even notice the power is out. It all depends on your power needs, budget and how often the lights go out! We’ll get into that later.

However, if you are like most homeowners who want a reliable generator to operate a few key appliances when the power goes out you may need a generator that can supply at least 7500 watts.  You’re probably wondering what 7500 watts means for you during a power outage.  Great question.

It all depends on what is important to you. If you have medical devices that require constant power, those devices are going to be at the top of your list.  This is a need, not a want.  Water, food, and shelter are also necessary to survive an emergency. So, after medical devices, you are going to need power for water, especially if you live in the country and have a well.  You’ll also need power for a fridge, freezer and a way to cook the food.

If the power goes out in the middle of the winter, you will need to keep your house warm. If the power goes out in Arizona in August, you bet you will need to run the air conditioning to survive.  Make a list of what is important to you and then add up the watts required to power those appliances, heaters, ovens, and fridges.

When determining your power needs you must consider the watts required to run the appliance and the watts required to start up the appliance. These are typically two separate energy loads.

On average, when you turn on your well pump you need about 1440 watts and an additional 500 or so watts to keep in running. Add the starting wattage and running wattage to determine how much total wattage needed to power that specific pump.

Repeat this math equation with every appliance you need in your home during a power outage. Some appliances, like a microwave, electric stove and oven do not require any startup wattage.  This will make is easier to add more appliances to your generator.  For a detailed list of running and startup watts for a specific appliance, check with your local power company or the manufacturer of the appliance.

When in doubt, ask a professional electrician to determine the watts you need to comfortably survive an emergency.  You never want to overload a generator.  In fact, adding too many appliances on a generator can put you at risk for a fire, overheating of the generator and reducing its lifespan.  Generators are an investment.  Even the smallest generators will run you a couple hundred dollars. Don’t overload the generator and find yourself replacing it in a few years.  It just doesn’t make sense.


Personal Financial Crisis
Personal Budget

Once you’ve narrowed down your power needs, it’s time to take a look at your budget.  How much generator can you afford? Do you anticipate using the generator a couple times a month or every few years?  If you expect to be using the generator often, it may be wise to invest in a high-quality generator that is hardwired directly into your home. If you expect to use a generator only a few times in the next decade a portable generator will most likely do the trick.

There are four types of generators, all with a different price point.  A standby generator is hardwired into your home.  A standby generator automatically kicks in when the power goes out. You may hardly even notice the power is out.  This type of generator typically has the capacity of 5,000 to 20,000 watts. That means you don’t have to decide between having hot water, keeping the fridge on or making coffee.

With a standby generator, you can most likely power your entire home for a long period of time.  In fact, if you have a standby generator, you may have neighbors knocking on your door asking to take a shower too! The standby generator is the most expensive with prices ranging from $5,000 to $15,000.  The more wattage a generator can supply, the more expensive it will be!

A portable generator tends to be the favorite and most affordable choice for families who don’t experience a whole lot of power outages but want to have a generator on standby just in case.  You never know when the next emergency will happen. The power could go out tomorrow and it may take weeks to restore.

A portable generator can easily be stored in your garage or shed and pulled out when you need it.  Just never turn on the generator in your garage.  Generators produce carbon monoxide, an odorless, deadly gas. In general, keep portable generators at least 15 feet away from your home and windows.

A portable generator can supply you with 900 watts to 8,000 watts or more.  As I mentioned earlier, you can easily power most of the basic household appliances with a 7500-watt generator.  Portable generators are budget friendly too.  The more watts the more it will cost you. With that said, a portable generator will run anywhere from a couple hundred dollars to $1,500.  The portable generator is much more affordable for the average family than a standby generator.

The portable generator, however, requires a little work on your end to get it connected to your house and running.  Power companies recommend a transfer switch installed on the electrical panel box of a home. This transfer switch will prevent the electrical current from the generator from back feeding on the power line.

Back feeding can kill or seriously injure power line crews as they work to restore the lines. An electrician can easily install the transfer switch to make it easy and safe to use your generator the next time the power goes out. With a portable generator, you will also need a backup supply of gasoline.

While affordable, portable generators tend to be exceptionally loud. Just keep that in mind.  If you want a silent or quieter generator research inverter generators and solar-powered generators. An inverter generator matches your power needs and adjusts accordingly. Basically, an inverter generator throttles the engine down when you’re not using a lot of power and throttles up when the power load is high.  Standard generators run at full speed all the time, regardless of how many appliances you are using. Inverters are quiet, use less fuel and they are energy efficient.

Inverter generators come in three sizes: large, midsize and camping versions.  The large inverter generators will provide you will about 5,000 watts. A midsize inverter produces between 2,000 and 4,000 watts. The rec version will give you a couple hundred watts up to about 2,000 watts. Inverter generators tend to be slightly more than portable generators but less expensive than a standby generator.

If you are looking for an eco-friendly way to power your home during an emergency, look into solar generators.  Advances in technology, make solar powered generators a great option for a family that wants to power a few lights, a fridge and maybe the occasional television show.  Solar generators harness the sun’s power and convert that energy into usable electricity. A battery in the solar generator stores the electricity for when you need it.  Solar generators don’t require gasoline to operate, so you can bring it into your home and plug your appliances directly into the generator.

Most solar generators have a variety of USB, 12 V and 120 V outlets to makes it easy to charge your cell phone, tablet, plug in your fridge and other basic appliances. Solar generators, however, will not power your well pump or other big appliances.  You can tether some solar generators together to give you more wattage, but it will only result in a couple thousand watts.  The average solar generator will give you up to 1500 watts.  A digital screen display makes it easy to determine how much energy you are using and how much you have left.

Solar generators are a great choice if you’re not worried about hot water or keeping a freezer running 24/7. This generator is best for smaller appliances, cell phones, and other basics.  Solar generators are a great choice for camping too. Solar generators range in price from a couple hundred dollars for 150 watts up to $1,200 for 1500 watts.  You certainly pay more for the wattage with a solar generator, but it’s a renewable energy source.  No need to buy fuel- the sun is your fuel.

The Frequency of Power Outages

Power Outage
Power Outage

When considering how big of an emergency generator to purchase, consider the frequency of power outages in your neighborhood.  If you live in tornado alley you may need a large generator will a big wattage load to help power tools, appliances, and other necessities.  If you live in Seattle, where the power goes out maybe once a year, a smaller portable generator may be just fine to meet your needs.

There’s no one size fits all generator.  What works for a family in Arizona, may not work for a family in Alaska where the brutal winter takes out power lines weekly.  If that’s the case, keeping the heat on inside your house is a top priority and requires a larger generator. If you live in Arizona, you will need that air conditioning stat.  Air conditioners require a lot of energy, especially if it’s a central system.

When you add up your power needs, take a look at your budget and track the frequency of power outages in your neighborhood, you make a well-informed decision about the size of a generator to purchase.  No matter what size generator you decide to purchase, you will be ready and prepared to keep your family safe during the next emergency and get through the next storm in comfort.

Related Articles: “What is the best solar generator for home use?” and “Do I really need a backup generator for my home?


Hi! I’m David. For most of my life I have been interested in emergency preparedness. Over the many years things have changed a great deal. From freeze dried food, to LED lanterns, preparing for an emergency has never been easier. The continual research I have done over the years have become the basis for this website. Now it is one of the most trusted sources to learn about emergency preparedness. Read More

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