Last update: May 2022
Some of the most common questions people ask before buying a generator are: What size generator do I need? What size generator do I need for my home? Which generator size is sufficient to arefrigerator and freezer? What size generator for 30 amp RV? How many watts do I need to power my MIG welder/storage pump/air compressor?
If you're looking for a generator for your home, chances are you need more power to power multiple devices. Large 10,000 watt dual fuel units such asWestinghouse WGen9500DFThey are the best choice for homeowners.
If you're looking for a generator for your home, chances are you need more power to power multiple devices. Large 10,000 watt dual fuel units such asWestinghouse WGen9500DFThey are the best choice for homeowners.
However, if you only need to run certain appliances (e.g. fridge and freezer) in an emergency, you can also use a smaller generator.
Take a look at the generator size chart below to get a better idea of what size generator you need to power your home.
| domestic appliances | required power | Our recommended generator |
|---|---|---|
| Fridge freezer | 2000 | Champion Power Team 200986 |
| Fridge and freezer, air conditioning (10,000 BTU), television, laptop, washing machine, lighting | 4500 | Westinghouse WGen9500DF |
| Most important devices in your household | 10000 | Westinghouse WGen9500DF |
If it is an RV Generator you are looking for:Champion 3400 dual fuel inverterIt's a great choice. This quiet 3000 watt inverter generator can power everything in your caravan including the air conditioning, fridge, TV and lighting circuits.
If it is an RV Generator you are looking for:Champion 3400 dual fuel inverterIt's a great choice. This quiet 3000 watt inverter generator can power everything in your caravan including the air conditioning, fridge, TV and lighting circuits.
If you need a more accurate estimate of how much power you need to run the devices you want, use oursGenerator power calculator:
How do I calculate which generator size is best for my needs?
The most critical value is the output power of the generator.
We measure itWatt (W).
Small camping generators produce between 1,000 and 3,000 watts.
Heavy household and construction site generators can produce over 10,000 watts.
This amount of power is usually enough to run the most critical devices as well as the most demanding power tools.
Now you need to estimate your power needs and figure out how much total power you need.
Step 1 - Create the list of devices you want to run
If you need a generator for your home, list all of the major appliances you will need to use during an emergency power outage.
Fridge, freezer, air conditioner and lighting circuits are some of the items to include in this list.
Step 2-use a calculatorabove to calculate the total power requirements for your selected devices.
There are two numbers to watch out for:
initial watts– this is the amount of energy that the device needs to start.
Motorized devices generally require more energy to start. A good example is a window air conditioner.
operating watts(ÖWatt nominal)– means how much power the device needs to run after the first start.
To give a better example, a typical 10,000 air conditioner initially uses 2,200 watts. You need that to boot in the first few seconds. After that, your energy needs drop. The air conditioner requires a constant supply of 1500 watts to operate.
When choosing a generator, you should pay attention to thisBOTHPay.
In the above case aInverter generator with 2200 watts startingand 1800 working watts like Honda EU2200icould run 10,000 BTU AC.
But youYou can't use a 2,000 output watts, 1,600 operating watts generator to power it.even if it meets the mileage requirements. The starting power of a generator is simply not enough here.
Step 3 -Choose a generatorSA little bigger than your needs.
It's always a good idea to buy a generator that offers extra power. There are several reasons for this.
First– It is always better to have a generator that is a bit too big than one that is too small. It's far better to have a few hundred more watts available than to end up with a generator suddenly shutting down due to overload.
second -Running a generator at full load can significantly reduce its lifespan.
third partyA generator running at 100% load makes a lot more noise. It can be a real hassle, especially if you plan on using it for camping or RVing.
So if you estimate your total power requirements to be 1600 watts operating, get a generator that can deliver at least 1800 watts of nominal power. If the total wattage of the selected devices is 6800 and the starting wattage is 8200, you will get aGenerator with 7500 watts nominal and 9500 watts starting power.
What size generator do I need to run the whole house?
You can power your main household appliances with a 5,000 to 7,500 watt generator. This includes things like a sump pump, fridge and freezer, and lighting circuits. A generator with around 7,500 watts of power can operate all of these devices at the same time.
For trailers, a 3,000 to 4,000 watt generator would be ideal.
Just to be 100% sure you should check that manuallyperformance of your devices.
They are usually listed on their labels and are expressed in watts or amps.
Read on to learn the difference and how to calculate it.
This will help you determine the generator size you need and what generator sizes are right for the application.
The numbers on the calculators are average estimates and should be used to get a better idea of your energy needs. However, because every home and decor is different, your needs may vary.
There is a question to ask yourself before buying a generator:
Do I need one to power the whole house OR just the essential appliances?
Do you live in a disaster-prone area that experiences frequent power outages? In that case, getting a larger generator, while it may be more expensive, would give you more peace of mind and be a good investment in the long run.
On the other hand, if you plan to only run a generator a few times a year in the event of a sudden emergency power outage, you can save a lot of money by purchasing a smaller generator that can run essential equipment.
Air conditioners, freezers, refrigerators, pressure pumps, lights, computers, and televisions are some of the devices you'll want to keep running during a power outage. They don't need an expensive whole-house backup generator or a high-power portable generator to power them.
use our calculatorto get custom accurate estimates and find out which generators are powerful enough.
Watts, Amps and Volts: What's the Difference?
Ampere (Ampere) (A) and Watt (W)they are simply different units used to calculate the total power consumed or generated by electrical equipment.
how oneVolt (V)– The vast majority of devices sold in the US follow the same standard and are classified120V. However, some power tools operate at a higher voltage (the most common being220V). MIG or TIG welders are the best known.
The power consumption is shown on the label on each device. It is expressed in amperes or watts.
If you know how many amps your tool or device needs to run, you can easily calculate your current needs as well. Just use the following formula:
Power = Amps x 120
Example:
You want to power a 120V MIG welder that draws 70 amps.
70 A x 120 V = 8400C
In this case you need at least one generator8.400runWattto operate your MIG welder.
A label on an air conditioner. As you can see this unit draws a maximum of 2500W. You would need a generator with at least that many watts to power that particular AC power. Source:Zwangsa.com
On the contrary, if you know the wattage and want to calculate the amperage of your portable devices, you can use this formula:
Amps = Power / Voltage.
Can I Use a Large Portable Generator to Power Sensitive Electronics?
Technically yes, but we don't recommend it.
This is because traditional high power generators often suffer from higher total harmonic distortion (THD). General consensus is that 3% THD is the upper limit for classifying performance as "clean" and perfectly safe for modern electronics. The state grid and backup generators operate well below this limit. Unfortunately we cannot say the same for most typical high power portable generators.
Using them to power your laptops, flat screen TVs or other modern electronic devices for hours can damage them.
There is good news -portable inverter generatorsThey don't suffer from the same problem and are safe to use to power sensitive electronic equipment.
A problem with most inverters is that they are too small. Don't expect to power your entire home from a single inverter generator.
However, most inverter generators have a parallel switching function. This means you can run two inverter generators in parallel and double their total output.
For example. if you have twoHonda EU3000iS Inverter GeneratorsIf you use them in parallel, you end up with 5600 watts of power. This is already enough to supply some important large devices with electricity in an emergency. You can also safely operate sensitive portable electronic devices.
However, if you choose a portable, conventional or inverter generator –One without is not possibletransfer key.
Using a portable generator to power a home without a switch is not the best idea. This can not only damage your devices and the power grid in the entire neighborhood, but can also lead to life-threatening electric shocks in the worst case.
What kind of generator do I need?
If you need a generator for backup power or to power energy intensive work equipment (like MIG welders), we recommend a large portable unit like thisWestinghouse WGen7500DF.
If you are looking for a motorhome generator, it is best to buy a compact, quiet inverter generator with at least 3,000 watts.This champion generatorIt's a popular and reliable choice.
What size Generac do I need?
Generac 7676It is an excellent choice for homeowners. It generated 10,000 initial watts and 8,000 operating watts, enough to power all of your home's vital appliances such as the air conditioner, refrigerator, and lighting circuits.
For RV campers we recommend theGenerac 7127 iQ35003500 watt inverter generator. It's much quieter than most other generators on the market (including Honda), making it an ideal choice for camping trips. Not only did we find it quiet, but it was also energy efficient. A full tank is enough to power the RV air conditioner and some other equipment overnight. It is an inverter generator that produces cleaner and more consistent power. This means that you can use it to safely charge your portable electronic devices such as laptops, smartphones, televisions, etc.
FAQs
What size generator do I need for my home? ›
Add up the Total Watts to determine how much power your home is likely to use during an outage. Divide the Total Watts by 1000 to find kilowatts. Multiply kilowatts x 1.25 to add a margin of safety and for future power needs. This is the minimum Generator Capacity required for your home.
How do you determine what size generator you need for your house? ›Add up the Total Watts to determine how much power your home is likely to use during an outage. Divide the Total Watts by 1000 to find kilowatts. Multiply kilowatts x 1.25 to add a margin of safety and for future power needs. This is the minimum Generator Capacity required for your home.
What size generator is needed for a 2000 square foot home? ›The average family with a 2,000 ft2 home may require up to 30,000 watts hours (30kWh) to power all of their devices, appliances, laundry, air conditioning, and heating units for a day. Around 5000 watts of AC output should simultaneously power the essential appliances in a 2,000 ft2 house.
What size generator is needed to run an average house? ›Some may need to use more appliances during a power outage while some may be enough with having just a few of them running. But in general, a generator that can provide between 5,000 and 7,500 watts would be enough to power a house.
How do I calculate what size generator I need? ›- Form a list of all items that will be powered.
- Determine the starting wattage (energy needed to turn it on) and running wattage (energy needed to operate it) for each piece of equipment. ...
- Calculate your total power requirement by adding up these kW or KVA figures.
If your home is 2,500 square feet or less, a generator with 20kW should suit your backup power needs well, particularly if you have gas heat and hot water. If the range top is also gas, all the better. 20kW is enough to run most house receptacles, lights, and up to a 5-ton central air conditioner.
Will a 12000 watt generator run a house? ›Whole House: Starting at about 12,000 watts, these generators can generally keep a home running without missing a beat. You'll be able to run lights, fans, TVs, refrigerators, computers, space heaters and pretty much anything else you plug into an outlet.
How big of a generator do I need to run a 1800 square foot house? ›ft.: 6 kW – 8.5 kW Residential Generator. 1,500-2,000 sq. ft.: 8.5 kW – 10 kW Residential Generator.
Can a generator be too big for a house? ›You, however, need to ensure that you choose the right generator size that meets your household needs. If you buy an undersized unit, it will strain to meet your power demands, shortening its lifespan. An oversized unit will result in unnecessary power loss and can damage your appliances.
How big of a generator do I need to run a 2 bedroom house? ›How Big of a Generator Do I Need to Run a House? With a generator rated at 5,000 to 7,500 watts, you can run even the most critical household equipment, including things such as refrigerator, freezer, well pump, and lighting circuits. A 7500-running watt generator can run all these appliances at once.
What size generator do I need to run a house with central air? ›
Standby generators have the strength to power central air conditioners, so you can return to a cool home. A 14-kilowatt standby generator could power a 4-ton central air conditioner. A 17-kilowatt model could run a 5-ton central air conditioner.
Is it worth getting a whole house generator? ›A home backup generator offers improved safety and security as well as convenience and efficiency. It also saves you money in the long run if you own a home and often leave for hours at a time.
How do I hook up a portable generator to my house? ›You simply plug the gen cord into the 20- or 30-amp outlet on your generator. The opposite end splits into several household outlets, where you can start connecting additional extension cords safely indoors.
Will a 30 amp generator run a house? ›If you are not intending on running your central air conditioning or do not have central air then chances are a 30 amp generator is perfect to power your home.
Do I need a special extension cord for a generator? ›If the MOST POWERFUL OUTLET on your generator is 30-amps (4-prong), you'll need a 30-amp (4-prong) cord. If it's a 30-amp (3-prong) outlet, you'll need a 30-amp (3-prong) cord.
How big of a generator do I need to run a refrigerator? ›Refrigerators and freezers use between 100 and 800 amps per hour. A generator that can deliver at least 2000 starting watts will be sufficient to run both the refrigerator and the freezer without any problems.
Is there a tax credit for a whole house generator? ›Generators used to generate electricity for your home may be eligible for federal energy tax credits if it meets certain government criteria. Your generator may qualify as a renewable energy source if it is powered by solar, wind, geothermal, or fuel cell energy.
What is the average cost to have a whole house generator installed? ›You can expect to pay anywhere from $1,500 to $5,000 to install a whole-house generator. Generally, large generators take longer and cost more to install than small generators. Additionally, if you're installing a generator in a hard-to-reach area, it can drive up installation costs.
What appliances will a 22kw generator run? ›A 22 kw generator will power a 3-4,000 square foot house.
It will run the HVAC equipment and the washer or oven at the same time.
If you want to run larger appliances such as refrigerators, air conditioners, freezers, heaters, etc. using a portable generator, then the 7,500-Watt Generator can provide the power to run those devices (not all at the same time though).
Can I run a generator for 12 hours? ›
While some generator models can run anywhere from eight to 12 hours, or even for multiple days, generators should never be left to run for weeks or months at a time. Essentially, this comes down to generators' engine construction, which requires not just fuel, but regular lubrication and routine maintenance.
Will a 10k generator run a house? ›You could run one or two high-powered appliances with a small generator but not more than that. The next benefit of choosing a 10,000-Watt Generator is you can power an entire house with it during emergencies.
What kind of generator is best for home use? ›Whole house generators (home standby generators) are the best generators for home use. They are designed to provide ample power for your appliances and HVAC systems. Portable generators are often used on job sites to power air compressors, nail guns, saws, hammer drills and other equipment.
Which is better Kohler or Generac? ›In terms of generator lifespan, you can expect Kohler models to outlive Generac models. And when it comes to customer service and warranty coverage, Kohler is the clear winner – allowing you to buy a generator with confidence that it'll last for many years to come.
How big should a home backup generator be? ›A 7,500-watt generator is generally a good size, unless you have a very large home or want to run every appliance you have on the generator. It can handle most of your household appliances, although it's a good idea to balance what you run at the same time.
Why does a generator need to be 20 feet away? ›as one hundred times more poisonous carbon monoxide gas than a car's exhaust. And, if the generator is operated too close to a house, especially near a window or door, the invisible and odorless toxic gas can easily enter the home, resulting in illness or death.
How close can a generator be to an AC unit? ›An air-cooled Generac generator with a steel or aluminum enclosure can now be installed as close as 18” from your home providing you install it at least 5ft. from a window or door opening, dryer vents, furnace vents, etc. and 3ft.
What happens if you overload a whole house generator? ›In the rare event of an overload, the generator's circuit breaker will trip, disconnecting the unit from the load. Simply correct the overload and reset the breaker in the generator. For more information, please consult your owner's manual or contact us.
How big of a generator do I need for a 3000 sq ft house? ›A 3,000-square-foot house with two central air conditioners, an electric range, and a whirlpool tub might require as much as 25kW to 30kW. A newer option is a "load-management system," a generator that can power everything in your house, just not all at once.
How many watts does it take to run a 1500 square foot house? ›If a home is 1500 square feet but only runs on electric, it could need 38 kilowatts-48 kilowatts worth of power from a generator. Compared to a home twice its size, 3000 square feet, if it's entirely run-on natural gas it could run on a generator that powers 20 kilowatts.
What can a 7500 watt generator run? ›
At 9375 starting watts and 7500 running watts, this unit can handle it all in an outage – lights, refrigerator, modem/router, security system, window AC, furnace blower, TV, computer, phone charger and more.
Can I run a 3 ton AC with a generator? ›If you have a 3-ton (30-Amp, 36,000 BTUs) air conditioner, you need at least a 14 KW generator. If you have a 4-ton (40-Amp, 48,000 BTUs) air conditioner, you need at least a 17 KW generator.
What size generator do I need to run a 1 ton AC unit? ›Simply multiply your unit's tonnage by 3,500 (1 ton = 3,500 watts).
What size generator do I need to run my AC and refrigerator? ›A 3,000 W generator will work with all standard refrigerators and freezers. This is also the most commonly used generator. A 5,000 W generator is typically used for very large refrigerators and freezers. The larger the appliance the more energy is needed to keep it functioning properly.
What is the downside of generators? ›Emissions: One of the major drawbacks of diesel generators is that they produce carbon dioxide, nitrogen oxide, particulate matter, and other dangerous exhausts that release into the atmosphere.
What is the lifespan of a whole house generator? ›As we mentioned earlier, the average whole home generator lifespan is between 20-40 years. However, this number is just an average.
What are the disadvantages of a home generator? ›The major disadvantage of an AC generator is that it has high levels of extra insulation due to largely associated voltages. Further, these generators are susceptible to sparks and heating issues, which may lead to electric shocks and even fires.
Do you have to turn off your main breaker when using a generator? ›For an extra measure of safety, switch your main fuses or circuit breakers to the “OFF” position. Be sure you understand them before hooking up the generator. Follow the manufacturer's instructions to properly ground the generator. Generators emit carbon monoxide.
Where is the best place to put a portable generator? ›NEVER run a generator indoors or in partly enclosed areas such as garages. ONLY use outdoors and far from windows, doors, vents, crawl spaces and in an area where adequate ventilation is available and will not accumulate deadly exhaust gas.
Can you hook a generator directly to your house? ›Your generator should have come with a cable to connect to your house. Plug it in, select which voltage you want (if you can), and do the same turn of the plug (about 15 degrees) that you did with the other end and the receptacle. Never plug a generator directly into a wall outlet or your home's wiring.
Should I run my generator on 120 or 240? ›
For higher voltage applications such as supplying certain tools or connecting to the house during an outage, the 240-volt option is important. If you're looking at 3000 watts or less, you're probably fine with a 120-volt generator. Otherwise, choose a generator with 120/240-Volt outlets.
How do I connect my generator to my house without a transfer switch? ›If you absolutely must connect your generator to your house without a transfer switch, you can use an interlock device/kit, an extension cord, or a dedicated outlet box (that is not part of the rest of the electrical system). Installing any of these devices requires you to contact a licensed electrician.
Do I need a 50 amp cord for my generator? ›Each of the outlets on your generator will have a certain amount of amps they can handle. You simply select a power cord that matches the most powerful outlet on your generator. So, if you have a 50-amp outlet, you'll need a 50-amp power cord. If you have a 20-amp outlet, you'll need a 20-amp cord.
Can I connect 2 generator cords together? ›Although individual portable generators can only put out so much power, it's possible to combine two of them to get double the wattage. This is called paralleling generators and is an easy workaround that will let you power larger loads like RV air conditioners with smaller units.
What is the longest extension cord you can use with a generator? ›If your extension cord is #16 gauge wire, you can have a cord up to 50 feet. For the same appliance, if your cord is #10 gauge, your maximum length is 250 feet.
Do I need a bonding plug for my generator? ›The only time you'll need a GFI transfer switch to connect the generator to your home, is if your generator is fully GFCI protected. Meaning, its 120/240-volt outlets are GFCI protected and without a GFI switch, it will create a ground loop and trip the circuit.
How big of a generator do I need for a 2000 sq ft house? ›The average family with a 2,000 ft2 home may require up to 30,000 watts hours (30kWh) to power all of their devices, appliances, laundry, air conditioning, and heating units for a day. Around 5000 watts of AC output should simultaneously power the essential appliances in a 2,000 ft2 house.
What size generator do I need for a 1200 square foot house? ›Here are some basic estimations based on different home sizes running the most essential appliances: 1,000-1,500 sq. ft.: 6 kW – 8.5 kW Residential Generator.
What size generator do I need to run my house with AC? ›Standby generators have the strength to power central air conditioners, so you can return to a cool home. A 14-kilowatt standby generator could power a 4-ton central air conditioner. A 17-kilowatt model could run a 5-ton central air conditioner.
How many kW generator to run a 2000 sq ft house? ›ft.: 6 kW – 8.5 kW Residential Generator. 1,500-2,000 sq. ft.: 8.5 kW – 10 kW Residential Generator.
Will a 15000 watt generator run a house? ›
With 15,000 watts of power, the XP15000EH Dual Fuel generator will keep your entire home running during a storm or power outage. DuroMax is the industry leader in Dual Fuel portable generator technology, with a full assortment ranging from digital inverters to generators that can power your entire home.
What will a 10000 watt generator run? ›At 12,500 starting watts and 10,000 running watts, this unit can handle it all in an outage – lights, refrigerator, modem/router, security system, window AC, furnace blower, TV, computer, phone charger and more.
What size whole house generator do I need for a 200 amp service? ›If you have a 200 Amp service panel, use a 15-20 kW GenSet (again use the larger size if you have air conditioning or large well pump). If you have a 400 amp service panel, use a 30-50 kW GenSet (if you have lots of air conditioning or other larger loads use the large size in the range).
Can you run a house on a 10kW generator? ›Though the 10kW – 12kW home standby generator likely won't power your whole home depending on its size, it's certainly enough to handle “the essentials” such as well pumps, appliances, etc., plus a little more in the event of a power outage.
Will a 2000 watt generator run an AC? ›If you've ever wondered if your 2000 watt generator will run an air conditioner, the answer is yes, but only a portable or window air conditioning unit. You can power most small home appliances with a 2000 watt generator very smoothly but your central air system will not run efficiently.
Is 500 hours a lot for a generator? ›On average, a standby generator can run for up to 3,000 hours powering a medium-sized home, though it is recommended you do not run a generator for longer than 500 hours continuously.
How much does a 10000 watt generator cost? ›The 10,000-watt generators we reviewed range in price from $2,900 to $4,100, which is far more palatable than the cost of bigger generators.
How many watts does an average house use? ›According to the Energy Information Administration (EIA), the average American home uses an average of 10,632 kilowatt-hours (kWh) of electricity per year. That's 29,130 watts (W) per day, which can be divided by 24 hours to get an average of 1,214 W to power a home throughout the day.
What can you run in your house with a 7500 watt generator? ›If you want to run larger appliances such as refrigerators, air conditioners, freezers, heaters, etc. using a portable generator, then the 7,500-Watt Generator can provide the power to run those devices (not all at the same time though).
How big of a generator do I need to run my HVAC system? ›Standby generators have the strength to power central air conditioners, so you can return to a cool home. A 14-kilowatt standby generator could power a 4-ton central air conditioner. A 17-kilowatt model could run a 5-ton central air conditioner.
How many things can you plug into a 2000 watt generator? ›
A 2,000-watt generator is enough to power most small household items, including toaster ovens, coffee makers, lights, and computers.