What Size Generator Do I Need?

“What size generator do I need?” is probably the most important question to ask when setting out on your mission to purchase the right generator you need for your personal requirements.

In the event of a power outage and the electric grid is down, the ideal generator will ensure that your appliances keep running and allow you to go about your business while you wait for power to be restored. I would like to share with you my experience with heavy-duty generators and small camping generators that I have tested throughout the years and help you choose the most suitable one for your needs. Your home backup generator doesn't have to be the most powerful one if it is only your laptop or TV you need to power.

Keep reading to learn how to choose the proper size and generator power without breaking the bank and burning essential appliances.

What Size Generator Do I Need?

Finding a portable or whole house generator that’s capable of handling all your power needs is perhaps one of the most important aspects of the purchase decision. If the generator you get is unable to meet your requirements., it won’t do any good since it can put unnecessary stress on the unit itself along with some of the appliances/devices connected to it.

Unfortunately, determining the exact size generator to buy is not the easiest thing since a lot of factors and considerations are involved. The following is an in-depth look at what you need to consider when buying a generator to ensure that you get the right size of generator for your home or outdoor requirements.

What Will You Be Using the Generator For: Power Sensitive Electronics or Critical Household Equipment?

There are a couple of factors that I usually pay close attention to when choosing a generator for my house and for my RV. Generator size goes by wattage, which refers to the amount of electrical power it can put out.

Other generator traits to keep in mind are starting or surge wattage and running wattage.

When you are looking to find the right size generator to buy, you must consider the intended usage. You have to determine what items you want to power, like the number and type of electrical appliances.

Heating and cooling appliances such as refrigerators and air conditioning units or the sump pump for your basement, for instance, tend to consume lots of power. You would therefore require a more powerful and usually larger generator to power such appliances simultaneously. Conversely, a smaller generator would be fine if you just want to power the lights in your home or a small power tool.

Different appliances will have different wattages. For instance, If I want to power a dishwasher that has a running wattage of 1200, I would connect a generator that can supply it with sufficient power. You can use a generator wattage calculator to see whether a generator you want to purchase can handle the load of all your appliances.

Now, that you have estimated the power demand, another important consideration to remember is when you power all these appliances. While you may add up the wattage of all your appliances/devices to determine what size of generator to get, it is important to understand that you will probably not be running some of them at the same time.

You probably won’t be running your power-hungry appliances like dishwasher, microwave, and TV at the same time. So, if you were to add up the wattage, you would probably end up getting a much larger generator than you really need. Therefore, I would like to recommend you a much better approach to power your entire house.

For instance, something else such as the microwave can be powered on when the dishwasher is off. If you use such an approach, you will find yourself actually avoiding paying extra for a larger output generator which full power you may not even need to utilize. It is not only economical but you can use selected electronics for an extended period during prolonged power outages.

You need to make a list of all the appliances you would want to power in case of an outage taking the points above into consideration. Whether you decide to stick with the essentials or aim for full home coverage, it is important to be thorough with your list.

What About Starting Wattage vs. Running Wattage?

It is important to get the right surge wattage and running wattage of the electrical devices you plan to power to calculate accurate power needs. You should ideally do your calculations early on to have a better idea of what generator to buy. You will find energy consumption listed at the following resources:

• Owner’s manual that comes with the equipment
• The equipment’s identification plates
• The equipment’s online webpage on the manufacturer’s website

Running Wattage

On the generator side, running watts refers to the maximum number of watts the generator is capable of outputting continuously without actually damaging it. On the device/appliance side, it refers to the consistent power level that a device/appliance needs to run. Devices such as light bulbs and hot plates typically have just one wattage rating, which is their required running watts.

Starting Wattage

On the generator side, starting watts refers to the maximum number of watts the generator is capable of outputting for a limited time. This allows the generator to increase its power output considerably, even though just for a limited time to meet the demands of appliances and equipment that require more wattage to get started. Such appliances/equipment are typically those with electric motors such as washers, refrigerators, and driers.

What Do I Need to Know About Watts, Amps, and Volts?

The amount of electricity the equipment needs to run is typically given in the form of Amperes (Amps), a unit of measure for electrical current. Volts are a unit of measure of how strongly a current is sent around an electric system.

The vast majority of domestic electric appliances sold in the United States are of a similar standard and rated 120V. Still, you will find some electric appliances running at a higher voltage, with 220V being the most common.

The energy requirements of each device will always be provided in various resources, as explained above. Once you know the Amps your appliance or tool requires to run, you can easily calculate its wattage using the following simple formula:

Wattage = Amps x Volts

You should then add up the total wattage needed to keep your appliances/equipment running to get the required wattage number for the generator you should get.

Ideally, the generator you choose should be capable of handling slightly more than your total wattage for safety. For instance, if you find the total wattage for the items you need to run as 10,000 watts, you should consider getting a generator capable of handling at least 12,000 watts.

Guide to Average Device Wattage

The following table shows the average wattage for some common appliances in your home and will assist you in answering your question; “What size generator do I need?”

Appliance	Running Wattage	Starting Wattage
2 Light Bulbs	140	0
Cell Phone Charger	25	0
Central AC	3,800	4,950
Electric Water Heater	4,000	4,000
Refrigerator/Freezer	1,600	800
Washing Machine	1,150	2,250
Laptop	250	250
LCD TV - 32"	100	0
Total:	11,065	12,250

Note: The sample wattages provided in this table are simply a guide. If you want the correct wattages for your calculations, please be sure to check the specific appliance or tool that you plan to be powering in case of power outages.

What Size Generator Do I Need? Important Considerations

If you buy a too-small generator, you will overload it or force it to supply more power than it can handle. If that happens, the generator may either overheat or automatically turn off, which may destroy not only the generator itself but also your expensive appliances.

If you buy a large portable generator, you will find yourself overpaying for the unit as well as the costs associated with operating it. Therefore purchasing an appropriate-sized generator is important to save costs and avoid equipment damage.

Here is a more in-depth look into why you should buy the right size generator you need:

1. Avoid Random System Failures

Once you learn how to size a generator for your needs properly, you will no longer have to worry about losing power due to system outages. If you work from home, you want to ensure you can continue working if the power goes out. Even if you don’t work from home, you cannot afford to have a power outage, especially during winter, or else you risk freezing to death. If you have a generator, however, you will never have to worry about any of that.

2. Enjoy a Longer Generator Lifespan

A generator can be a sizeable financial investment so focus on buying a quality generator with a long life span. However, finding a good model can be daunting, so I have created a list of the best portable generators on the market to ease your search.

It is important to have a generator that’s properly sized to ensure that it does not break down prematurely, which could cost thousands of dollars to repair or replace.

3. Avoid Sporadic Shutdowns Caused by Overloading the System

The maximum power capacity for your needs is another key advantage you gain by getting an appropriately sized generator for your needs. You will no longer need to worry about appliance/device failure from capacity overload.

Many generators are versatile, meaning you can utilize them in your home, RV, or when camping. You can purchase a portable generator to satisfy your need of powering sensitive electronics, and have an extra generator to increase the total power output to power a fridge. For instance, you can have two inverter generators and use them in parallel for better efficiency.

When looking for a generator to buy, it is important to choose one that gives you maximum power whenever you need it. You can use the guide provided here to find the right size of generator for your needs and enjoy an excellent performance at all times.

5. Ensure the Safety of Everyone

Safety is always of utmost importance when dealing with electric equipment. When your appliances rely on a generator for power, each of them must have sufficient power without the risk of short circuits or any other mishaps that may lead to safety issues and concerns.

Other Important Considerations When Buying a Generator

Conventional vs. Inverter Generator

You might not know it now but there is a quite a difference between a conventional portable generator and an inverter generator. To better understand which one will be best to power your portable appliances, read my in-depth review of inverter generators. In short, they are best to power your sensitive electronic devices because they produce clean power with low total harmonic distortion (THD). Powering small household appliances and gadgets has never been easier and safer.

Home Standby Generator vs. Portable Generator

If you have a large house and want to power your appliances whenever the power goes out, you could consider a standby generator. Larger standby generators are also referred to as whole house generators. Of course, your budget is an important consideration here as these models can be quite expensive and have installation costs. Also, a transfer switch is required, adding to the expense.

If camping, RVs, tailgating, or work sites are your principal interests, then a portable generator will be your best bet.

Budget

Budget planning is important since it keeps your household running smoothly. So, ensure that you plan your budget such that buying the generator and supporting its repair/maintenance is feasible for your financial situation.

Fuel

Generators typically use a fuel source such as propane, diesel, kerosene, and many others for the generation of electricity. It is important to decide what kind of generator you would like to buy based on the fuel used before you ever head out to buy your generator. Portable generators typically use either propane or natural gas.

Features

It is always a good idea to look for certain features when buying a generator, such as automatic shutdown, automatic voltage regulation, and automatic cooling. The generator should also be equipped with the proper safety features to avoid any mishaps.

Noise Level

It is always a good idea to check the noise levels (in decibels) and ensure that the generator muffler is of excellent quality so that it does not sound like a truck’s engine. The noise level is a particularly important consideration when getting a generator for recreational applications such as camping.

Find out what we consider to be the quietest generator.

What Size Generator Do I Need? Final Thoughts

There are a lot of generator options to choose from, so we hope this information will help you choose the right size generator you need. The best generator is one that’s perfectly matched to power all the appliances/devices you want to run in case of power outages.

If you buy a generator that’s too big, it will not only be expensive to buy but also won’t necessarily run as efficiently as the properly matched size. If you buy a portable generator that’s too small, however, some of your appliances may not be compatible, which means that the equipment may become damaged, and the generator’s lifespan may be reduced.