What Size Generator Do I Need To Run Refrigerator And Freezer?

During blackouts and in emergencies, running most essential appliances like refrigerators and freezers is important for keeping the food fresh and edible until the blackout is over.

A large enough generator can power not only refrigerators and freezers but other home appliances, including lights, TV, communication devices, and similar, helping people endure the emergency more easily. But how large generator is large enough?

Updated: July 24, 2023.

On This Page:

• Refrigerator and Freezer Power Requirements
• Running vs. Starting Power
• Generator Types
• Frequently Asked Questions (FAQ)
• Few Final Words

Refrigerator and Freezer Power Requirements

The power requirement of refrigerators and freezers depends on their size and age - newer, energy star compliant units require less power to operate than the older units. For example, a modern refrigerator/freezer typically requires:

• large home refrigerator: 200-400 running watts, 1000-1200 starting watts,
• average home refrigerator: 100-250 running watts, 700-1000 starting watts,
• small home refrigerator: 75-150 running watts, 400-600 starting watts,
• compact home/RV refrigerators: 40-50 running watts, 80-120 starting watts.

On the other hand, older energy star non-compliant units require up to 700-1000 running watts and 2000-3000 starting watts.

Note: even if You don't have issues with the mains power, blackouts, and emergencies, if You have an older refrigerator (with or without a freezer), consider replacing it with a new, energy much more efficient unit.

In order to figure out the exact power requirements of your refrigerator, check its documentation or label which can often be found at the backside of the fridge (or on the doors or similar places).

Running vs. Starting Power

Refrigerators, freezers, washing machines, drills, fans, and similar appliances and tools feature electric motors that require much more power when starting.

For example, suppose an average energy star-compliant home refrigerator and freezer requires 250 watts continuously. In that case, it may require 1000-1200 starting watts - such a power surge can be strong enough to overload the generator, causing its safety system to disconnect the generator from the external load, essentially powering off the refrigerator and other loads, if present.

This can be avoided by using a large enough power generator and connecting the external loads in a specific order - refrigerators and other loads with electric motors first, and only then other loads like TV, lights, multimedia, communication devices, and similar.

Refrigerator Duty Cycle

Refrigerators' and freezers' motors don't run continuously; they operate On/Off with a duty cycle of ~35% for refrigerators and ~65% for freezers.

Note: the actual duty cycles depend on numerous details, including ambient temperature, sun exposure (if the unit is near the window), energy rating of the unit, how often the unit is open, etc.

Considering the required energy, this is great. However, every time refrigerator or freezer starts, the generator is required to provide full Starting Watts to the unit every time the unit is starting (so, not just once).

Thus, when calculating the required wattage of the generator, be sure to use the Running Watts of the refrigerator.

Before buying a suitable generator, it is a good idea to make a list of required home appliances and other loads that must operate during the blackouts - for safety reasons, always go for a somewhat stronger generator.

For most homes, smaller closed-frame quiet power inverter generators with output power in 2000-4000 Watts are the most suitable units:

A power generator with a noise level of below 50 dB when running @25% is considered a quiet unit, but some of these units are so quiet that, when not heavily loaded, one must come close to the unit to verify if it is running or not. 

Generator Types

There are several generator types that are suitable for powering refrigerators and freezers, but other home appliances as well - just be sure to start the units with electric motors first.

Power Generators

Power generators burn fossil fuels and emit dangerous fumes that contain Carbon Monoxide (CO) and MUST be operated outside, at some distance from home, down the wind - before running any power generator, be sure to read its Owner's Guide thoroughly, especially safety features, issues, and procedures.

Power generators may use gasoline (gas), LPG (Liquid Propane Gas), natural gas, diesel, or a combination of two or more fuels.

Having a dual-fuel or tri-fuel power generator allows the user greater freedom in finding suitable fuel for the power generator, which can be an issue in emergencies when gas is usually the first one to be sold out.

But, when the fuel tank is empty or the propane bottle is empty, all the user has to do is to fill the gas tank or connect a new propane bottle and the power generator can resume its operation.

Solar Generators/Power Stations

Solar generators, also known as Power Stations, convert the energy stored in batteries (DC power) to provide AC power for external loads.

Unlike power generators, solar generators may operate safely indoors since they don't emit any fumes or gasses. Also, solar generators are very quiet during operation.

When the batteries are discharged, they can be recharged using mains power, solar panels, or - a power generator.

Many advanced models of solar generators support so-called pass-through charging - the unit can be recharged, for example, with solar panels, and can provide power to external loads at the same time.

Obviously, both power generators and solar generators have their pros and cons - in many cases, having both of them can significantly ease the crises when the power is gone for a longer period of time.

Note: Large Uninterruptible Power Supply (UPS) units can also be used to power refrigerators and freezers during emergencies - essentially they are very similar to solar generators/power stations, except UPSs are larger units usually placed on fixed positions at homes with automatic switch from the mains power to the battery.

Also, some solar generators/power stations can be used as small, portable UPS units, blurring the borderline between UPS units and solar generators/power stations.

Frequently Asked Questions (FAQ)

Here are some of the most common Frequently Asked Questions (FAQ) about powering freezers and fridges using power and solar generators:

Will a 1500 Watt generator run a refrigerator?

Generally, yes, a power generator with 1500 Running Watts (Starting Watts in the 1800-2000W range) will run a refrigerator as long as the refrigerator's Starting Watts are below 1500 Watts.

However, this is a very narrow safety margin.

Luckily, most modern home freezers and refrigerators require far less than 1000W when starting (often in the 200-600W range, model dependent), allowing the 1500W generator to easily power such appliances.

Note: due to the 30-40% Duty Cycle of the refrigerator, it is recommended to power it using a solar generator/power station or power inverter/deep-cycle battery combination, which can be recharged using a power generator.

Can a generator damage a refrigerator?

When the refrigerator is powered by an inverter power generator with very low Total Harmonic Distortions (THD ≤3%), the danger of any damage due to the output power is negligible.

However, powering modern refrigerators and freezers with classic generators that feature THD in the 20-25% range can cause various issues, even damage.

Most solar generators feature (almost) pure sine wave output and are suitable for powering sensitive electronics and appliances.

Power inverters with modified wave output should be replaced with pure sine wave output units when powering newer refrigerators, freezers, and other modern appliances - just in case.

 

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Few Final Words

If You are looking for a generator to power your refrigerator and freezer during blackouts, go for a strong enough power generator and/or solar generator.

And when connecting and turning the units On, always first start units with electric motors (refrigerators, washing machines, fans, air conditioners, etc.) to prevent overloading the generators - if they are overloaded, their safety systems disconnect external loads, practically shutting them off.

Note: again, never operate power generators indoors - they must be operated outside, at a certain distance from home. On the other hand, solar generators may be operated indoors - in unsure, always read the manuals first!