When it comes to providing backup power during a power outage, homeowners and RV owners have two main options: power inverters or portable generators. Both have their pros and cons when it comes to power output, fuel usage, noise levels, and overall convenience. Choosing between a power inverter or generator often comes down to assessing your specific power needs and usage requirements.
What is a power inverter?
A power inverter is a device that converts direct current (DC) power from a battery to alternating current (AC) power that can be used to run household electronics, appliances, tools, and other devices that typically require a standard AC wall outlet.
Power inverters work by using a transformer to change the voltage from DC to AC current. This allows you to plug electronics designed for standard AC power into your car, boat, RV, or any other battery-powered setup.
Some key advantages of power inverters include:
- Compact size and portable design
- Silent operation generates no noise
- Can provide power for small loads from a car battery or other DC source
- Doesn’t require fuel or engine operation
Power inverters come in two main types:
Modified sine wave inverters
Modified sine wave inverters produce a waveform that resembles a sine wave but has some differences. This type of power can run most electronics but some devices, like certain lasers, drills, and medical equipment may not work properly. Modified sine wave inverters are cheaper than pure sine wave models.
Pure sine wave inverters
Pure sine wave inverters produce a smooth, continuous sine wave just like the power supplied by an electrical outlet. They can safely power sensitive electronics and medical devices. Pure sine wave inverters are more expensive but provide power that is safe for all devices.
What is a generator?
A generator is a gasoline, diesel, or propane-fueled engine that runs to produce electrical power. The engine turns an alternator which generates AC power that can be used to run appliances, tools, medical devices, and other equipment.
Generators provide a critical backup power source during storms, emergencies, or any situation where the electrical grid goes down. They allow you to produce temporary power anywhere needed, independent of the utility company.
Some benefits of generators include:
- High power output can handle larger loads
- Can run high-wattage appliances like refrigerators, electric ranges, and medical devices
- Provide backup power for an entire home or building
Portable generators range greatly in size and power output. Small portable generators may produce only 1,000-3,000 watts while large standby whole house generators can put out 15,000-20,000 watts or more.
The main drawbacks of generators are that they require fuel, produce fumes, make noise, and must be operated/refueled regularly to supply power. Professional installation is recommended for permanent standby generators.
Comparing power output
One of the biggest differences between power inverters and generators is the amount of power they can realistically provide.
Power inverter power output
Small power inverters designed for use in cars and RVs typically provide between 100-400 watts of continuous power. Medium sized inverters may offer 600-1500 watts. Large inverters can deliver 2000-3000+ watts continuously.
The amount of power an inverter can supply depends on the capacity of the battery bank it is connected to. Batteries provide a finite amount of energy before needing to be recharged.
Trying to draw more power than the inverter or battery bank can handle will cause automatic shutoff to protect the system. Power inverters are best for running smaller loads like phones, laptops, TV’s, game consoles, and certain small appliances.
Generator power output
Portable generators are able to provide much more power than inverters, ranging from 800 watts for small portable models up to around 17,500 watts on heavy-duty gasoline generator models.
This higher power output makes generators better suited for high wattage loads like electric stoves, electric hot water heaters, home HVAC systems, pool pumps, and similar appliances.
Standby home generators that run on natural gas or propane can provide even more power when needed, ranging from 10,000 watts on smaller units up to 150,000+ watts on industrial generators.
The runtime of gasoline generators is limited by the fuel capacity of their gas tank. An 8 gallon tank might provide 6-12 hours of power depending on the load. Standby generators with large external fuel tanks can run for days on end.
Noise level comparison
One of the main advantages of power inverters is that they operate very quietly with no noise since they have no moving parts. This makes them ideal for use while camping or in other settings where you don’t want the loud noise of a generator running.
Even small portable generators produce 65-75 decibels of noise which is about as loud as a vacuum cleaner. Larger generators are even louder, producing up to 95+ decibels of noise at close range. This requires placement far from dwellings to prevent disrupting the peace.
Here is a noise level comparison between power inverters and different sized generators:
Noise level in decibels (dB)
| Power inverter | 0 dB (silent operation) |
| 1000 watt portable generator | 65-75 dB |
| 3000 watt portable generator | 70-80 dB |
| 5000 watt portable generator | 75-85 dB |
| 6000+ watt home standby generator | 60-70 dB |
As you can see, power inverters provide silent running compared to the loud drone of portable generators. Larger home standby generators can provide quieter operation by being permanently installed away from the home. But any engine-driven generator will make considerable noise when running.
Fuel requirements
Another major difference between power inverters and generators is their fuel requirements.
Power inverters don’t require any traditional fuel source. Instead, they draw power from a linked battery bank which could be a 12V car battery, a 24V battery setup, or a large 48V battery bank in an off-grid home or RV.
These battery banks do need to be charged to replenish their capacity. Methods for charging batteries include:
- Driving your car/RV to recharge from the alternator
- Plugging into shore power when stopped
- Using solar panels or wind turbines to charge
- Running a gas generator periodically to top off batteries
Generators require a ready supply of gasoline, diesel, or propane fuel in order to operate. This requires periodically refueling the generator as the fuel level gets low. Diesel and propane generators have the advantage of accessing external fuel tanks that don’t have to be manually filled as often.
Fuel consumption varies based on generator size and load. A 5000 watt gas generator might use 0.5-1 gallons per hour under typical loads. That equates to 4-8 hours runtime from a full 5 gallon tank before needing to refuel.
Inverters win out in terms of fuel use since their battery banks are silently recharged versus generators that constantly consume fuel when running.
Reliability comparison
Both power inverters and generators can provide years of reliable service if properly sized for your intended loads and maintained according to manufacturer recommendations. However, generators tend to require more frequent maintenance.
Power inverters have no moving parts and simply convert DC to AC power electronically. As long as they are not overloaded and can run within their output capacity, inverters will typically provide maintenance-free operation for 5+ years. Heat sinks and cooling fans may require periodic cleaning.
Portable generators have more maintenance requirements including:
- Oil changes
- Air filter replacement
- Fuel stabilizer to prevent stale gas
- Spark plug replacements
- Regular exercise to prevent fuel varnishing
These tasks are essential for proper generator operation but add to the routine maintenance requirements. Stationary standby generators have similar maintenance needs, best handled by an annual service contract with a generator maintenance company.
Convenience and ease of use
For applications like off-grid solar power or RV usage, power inverters offer greater convenience and ease of use versus portable generators.
Inverters silently produce power at the flip of a switch or press of a button. Many have remote controls or digital interfaces that allow power management from inside your RV or home.
Once an inverter is installed and connected to your battery bank, using it takes no extra effort. There is no noise, fumes, or need to go outside and start up a generator. Power is available on-demand.
With a generator, anytime you need power you have to:
- Move the generator outside and set it up
- Check the oil and fuel level
- Make sure you have enough gasoline on hand
- Start up the loud gas engine
- Run extension cords inside to appliances
- Periodically refuel the generator
For home backup power, standby generators do start automatically when the power goes out. But they still require the same maintenance and have a finite runtime until fuel runs out. Refueling requires going outside to the generator.
For most applications, inverters provide silent, convenient power at the flip of a switch. Generators require significantly more interaction and preparation for use.
Cost comparison
Both power inverters and generators are significant purchases that provide years of service. Here is an overview of typical costs:
Power inverter cost
Small 100-400 watt power inverters $50-$200
Medium 600-1500 watt inverters $200-$500
Large 3000+ watt inverters $800-$2500+
Larger inverters may require expensive additional battery banks to power them and reach their full wattage capacity. The inverter itself is just one component in an off-grid or backup power system.
Generator cost
Small portable generators $500-$1500
Mid-size whole house backup generators $3000-$6000
Large standby generators $6000-$15,000
A standby home generator will also require professional installation and hookup to your home’s power distribution panel. This can easily add $2000-$5000+ to the project cost. Expect maintenance contracts around $250 per year.
While generators themselves tend to cost more than inverters, you don’t need to invest in external batteries for generator systems. But fuel costs do need to be factored in with generators.
Environmental impact
Generators burn gasoline, diesel, or propane as their fuel source while running. This creates emissions and contributes to air pollution. The environmental impact depends on how often and how long you need to run your generator.
Some estimates indicate that using a mid-sized 5000 watt portable generator for 500 hours annually produces emissions roughly equivalent to driving a typical passenger car for 6,000 miles per year.
Power inverters utilize stored electricity from clean sources like solar panels or wind turbines. Even if you ultimately charge batteries from the grid, inverters allow stored renewable energy to be used on-demand. This provides environmental benefits compared to directly burning fossil fuels to generate power.
For solar homes or off-grid applications focused on sustainability, inverters support clean energy storage from renewable sources. This allows “green” power usage with zero emissions.
Safety considerations
Both power inverters and generators demand proper safety practices to avoid electrical hazards, fire risks, or carbon monoxide poisoning.
Power inverters should be used caution when installing and wiring to your battery bank. Proper fuse protection is crucial to prevent dangerous shorts or overloaded wiring. Invertors produce the same dangerous household AC power as an outlet, requiring the same precautions.
Gasoline generators pose a much greater safety hazard if improperly used. The Consumer Product Safety Commission estimates that portable generators cause around 70 deaths from carbon monoxide poisoning annually along with thousands of injuries.
You should never run a generator indoors or near windows. Deadly exhaust gases can easily accumulate inside structures. Carbon monoxide detectors are recommended anytime a generator is used nearby. Fuel should be stored properly out of reach of children.
Inverters simply transform battery power and avoid the complex safety needs of fuel-powered generators. But electrical safety is still critical when installing and operating any high wattage inverter connected to batteries.
Inverter vs generator for RVs
For RV usage, inverters offer most of the benefits over portable generators. An installed RV inverter can power appliances, lights, and electronics without any noise, fumes, or hassle.
Running a generator means packing it up, setting it outside your RV site, running extension cords inside, and refueling it periodically. This disrupts your camping experience and annoys your neighbors.
Inverters allow silent overnight power with just the flip of a switch. Most RVs have outlets designed for shore power that an inverter can supply power to with ease. Just monitor your battery voltage to avoid over-draining.
For medium to large RVs, you may want both an inverter for convenience along with a portable generator for occasional high-power needs like running roof A/C units. This hybrid approach gives you the best of both systems.
Inverter vs generator for backup power
For home backup power during outages, standby generators offer whole-house coverage that inverters can’t match for high-wattage loads. A standby generator kicks in automatically when the power grid fails.
An inverter can provide limited backup power for lights, appliances, and critical medical equipment. But most battery banks don’t offer the long-term energy storage needed for outages lasting more than several hours. Refueling generators provides longer runtime.
Combining both a standby generator and a battery inverter setup can provide the best home backup solution. The generator handles heavy loads automatically while the inverter powers smaller circuits.
Combining inverters and generators
While inverters and generators both have pros and cons, you don’t necessarily have to choose between them. Using inverters and generators together provides benefits that offset each technology’s weaknesses.
Ways to combine them include:
- Use an inverter for low-power needs, and run a generator occasionally to recharge batteries.
- Install an automatic standby generator for your home’s key circuits, while using an inverter to power medical devices, electronics, and small appliances.
- Use solar panels to charge batteries that power an inverter, and have a generator for backup when needed.
Every off-grid home or RV should consider having both inverters and a generator on hand. This provides silent everyday power from the inverter along with a backup generator for high-power demands.
Careful planning of your backup power system lets you take advantage of both technologies uniquely strengths.
Conclusion
Power inverters and generators both have specific benefits that make them suited to certain backup power and off-grid uses.
Inverters provide:
- Silent, clean operation from batteries
- Highly portable and easy to use
- Lower wattage output suitable for lights and small devices/appliances
- Zero emissions
Generators offer:
- Higher power output to handle larger loads
- Unlimited runtime with adequate fuel supply
- Whole house power backup possible with standby units
- No need for separate battery bank
Most homeowners and RVers will benefit from having both technologies available. Inverters provide convenient everyday use from stored battery power. Generators offer high-wattage backup for greater demands.
Your specific power requirements will determine whether an inverter or generator is the best solution. For mission critical medical devices or electronics, inverters typically provide cleaner and more reliable power. To run large loads like A/C units, electric stoves, or whole home backup, a generator is the better choice.
By understanding the strengths of each approach, you can install an integrated system that uses inverters and generators together for optimal reliability and performance.
