What Appliances Use the Most Power From a Generator?

A practical guide for homeowners preparing for blackouts, storms, and backup power

When the power goes out, your generator becomes the heart of the home. But not every appliance deserves a spot on it.

A fridge, a few lights, a modem, and a phone charger might barely trouble a suitable generator. But switch on an air conditioner, oven, hot water system, heater, or clothes dryer, and the load can climb fast.

That is where many people get caught out. The appliances that heat, cool, pump, or spin usually draw the most power. Some also need an extra burst of energy just to start. If you do not allow for that surge, your generator may trip, stall, or fail to run the appliances you actually need.

If you are planning for storm season, rural outages, or backup power at home, it is worth understanding your appliance load before choosing a generator. You can also compare different generators for home backup if you already have a rough idea of what you need to run.

Here is a practical breakdown of which household appliances use the most power from a generator, what to prioritise during a blackout, and how to avoid overloading your setup.

Why appliance wattage matters

Choosing a generator for home backup starts with one simple question:

What do you actually need to run?

A small generator may be fine for lights, charging devices, a fridge, and a few basic comforts. But larger appliances can quickly push it beyond its limits.

Heating and cooling appliances are usually the biggest power users. That includes air conditioners, electric heaters, ovens, hot water systems, dryers, pumps, and some power tools.

Understanding the difference between light loads and heavy loads helps you:

• Choose the right generator size
• Avoid overloading your generator
• Prioritise essential appliances during an outage
• Reduce fuel waste
• Keep your home safer and more comfortable

If you are still unsure where to start, a generator sizing tool can help narrow things down based on the appliances you want to power.

The appliances that use the most generator power

Not all appliances are equal. Some barely make a dent. Others can drain your available generator capacity very quickly.

As a general rule, the most power-hungry appliances are the ones that create heat, remove heat, or use motors.

1. Air conditioners

Air conditioners are often one of the biggest loads people try to run during a blackout.

A smaller unit may use around 1,000 watts, while larger systems can use 2,000 watts or more. In very hot conditions, the load can climb even higher because the unit needs to work harder to maintain temperature.

Air conditioners can also require a higher starting surge when the compressor kicks in. That means your generator needs enough spare capacity, not just enough to cover the running wattage.

If cooling is one of your main priorities, you may want to look at larger home backup options or quieter inverter generators, depending on your setup and appliance load.

2. Electric heaters

Electric heaters are simple but power-hungry. Many use between 1,000 and 1,500 watts continuously.

Unlike a fridge or pump that cycles on and off, a heater can keep drawing power the whole time it is running. If you combine it with other heavy appliances, it can quickly eat into your generator’s available output.

3. Hot water systems

Electric hot water systems are among the heaviest household loads.

They can use around 3,000 to 4,000 watts, depending on the unit. For many homes, running an electric hot water system from a portable generator is not practical unless the generator is large enough and the setup is suitable.

During an outage, it is usually better to treat hot water as a non-essential load unless your generator has plenty of capacity.

4. Electric ovens and stovetops

Electric ovens and stovetops can draw a huge amount of power, especially while heating up.

Typical usage can range from around 2,000 to 5,000 watts. That makes them one of the first appliances to skip during a blackout if you are trying to conserve generator capacity.

For short outages, many households are better off using lower-power cooking alternatives where safe and appropriate.

5. Clothes dryers

A dryer combines heat with a spinning drum motor, which makes it a heavy generator load.

Some dryers can use up to 3,000 watts. Unless you are running a large generator with enough headroom, a dryer is usually not worth powering during an outage.

It is better to save your generator capacity for refrigeration, lighting, communication, medical devices, and basic comfort.

6. Refrigerators and freezers

Fridges and freezers are essential during a blackout because they protect your food.

The good news is that they are not usually as demanding as heaters, ovens, or dryers once running. A fridge or freezer may use anywhere from around 100 to 800 watts depending on size, age, and efficiency.

The catch is the starting surge. A fridge compressor may need several times its running wattage for a short moment when it starts.

For example, a fridge that runs at 200 watts may need closer to 600 watts to start. If your generator is already close to its limit, that surge can trip it.

7. Washing machines

A washing machine is usually more manageable than a dryer, but it still uses a motor and may draw around 500 watts depending on the cycle.

If your generator has enough capacity, you may be able to run a washing machine occasionally. But during a short outage, it is usually less important than refrigeration, lighting, medical equipment, and communication.

8. Water pumps

Water pumps can be big power users, especially pool pumps, bore pumps, pressure pumps, and larger household pumps.

Some may use 1,000 to 3,000 watts or more. Like fridges, pumps can also have a higher starting surge because of the motor.

If your property relies on a pump for water, this should be considered early when sizing a generator. For a deeper breakdown, this guide on what size generator is needed to power a house is a useful next step.

9. Power tools

Power tools vary widely.

Some smaller tools may use a few hundred watts, while larger tools can draw 2,000 watts or more. Saws, grinders, compressors, and other motor-driven tools may also need extra starting power.

For worksites, sheds, and rural properties, tool usage should be added carefully when choosing generator capacity.

Typical appliance wattage guide

Here are the household appliances that usually draw the most power from a generator:

Air conditioner: 1,000–2,000 watts or more Air conditioners can use a lot of power, especially in extreme heat. They may also need extra starting power when the compressor turns on.

Electric heater: 1,000–1,500 watts Electric heaters draw steady power while running, which can quickly reduce your available generator capacity.

Hot water system: 3,000–4,000 watts Electric hot water systems are among the heaviest household loads and are often not practical to run on smaller portable generators.

Electric oven or stovetop: 2,000–5,000 watts Cooking appliances can use a huge amount of power, especially while heating up.

Refrigerator or freezer: 100–800 watts Fridges and freezers are usually manageable once running, but they can need a higher start-up surge when the compressor kicks in.

Washing machine: Around 500 watts A washing machine may be possible to run depending on your generator size, but it is usually less urgent than refrigeration, lighting, and communication.

Clothes dryer: Up to 3,000 watts Dryers use a lot of power because they combine heat with a spinning motor.

Power tools: 500–2,000 watts or more Power usage varies widely depending on the tool. Larger tools may also need extra starting power.

Water pumps: 1,000–3,000 watts or more Pool pumps, bore pumps, and pressure pumps can be major generator loads, especially at start-up.

These figures are general estimates only. Always check the appliance label, manual, or manufacturer specifications before relying on exact numbers.

What to prioritise during a blackout

When you are running on generator power, the goal is not to power everything. The goal is to power what matters most.

Start with essentials:

• Fridge and freezer
• A few lights
• Medical equipment
• Phone charging
• Internet modem or communication devices
• Fans or basic heating, depending on the season
• Water pumps, if required for the property

Then consider comfort items if your generator has enough spare capacity.

Try to avoid running multiple heavy appliances at the same time. For example, running an air conditioner, oven, dryer, and hot water system together can overload many generators.

A smarter approach is to rotate loads. Run the fridge, lights, and essentials continuously, then use heavier appliances one at a time only if your generator can handle them.

If you are comparing options, browse generators in Australia by size, type, and application before deciding.

Starting watts vs running watts

This is one of the most important things to understand.

Running watts are the watts an appliance uses once it is operating normally.

Starting watts are the extra watts some appliances need for a short burst when they first turn on.

Motor-driven appliances are the common ones to watch. This includes fridges, freezers, pumps, air conditioners, compressors, and some tools.

For example, a fridge might only need 200 watts while running, but it may need around 600 watts to start the compressor.

That starting surge matters. If you only add up running watts, you may think your generator has enough capacity when it does not.

A good rule is to leave headroom. Do not run your generator constantly at its maximum rating. Give it breathing space for appliance surges and safer operation.

How to avoid overloading your generator

To get more from your generator during an outage, keep the setup simple.

First, list the appliances you want to run. Then write down the running watts and starting watts for each one. Add up the essentials first before adding comfort items.

Next, avoid switching everything on at once. Start with the largest essential appliance, let it stabilise, then add smaller loads gradually.

It also helps to unplug non-essential appliances. That way, you are not wasting power on devices you do not need.

If you want a more tailored starting point, use True Gear’s generator sizing tool to match your appliance needs with the right backup power option.

A quick safety reminder

Portable generators should be used carefully.

Never run a petrol or diesel generator indoors, in a garage, in a carport, in a basement, or in any enclosed or partly enclosed area. Generator exhaust can produce carbon monoxide, which is dangerous because you cannot see or smell it.

Run the generator outdoors, away from windows and openings, follow the manufacturer’s instructions, keep it dry, and turn it off before refuelling.

Placement matters too. If you are unsure, read this guide on how far a generator should be from a house before setting one up.

If you want to connect a generator to your house wiring, speak with a licensed electrician. Do not attempt unsafe backfeeding or DIY electrical connections. For Australian homes, this guide explains how to connect a generator to your house safely.

Final thoughts

The biggest generator power users are usually appliances that heat, cool, pump, or use large motors. Air conditioners, electric heaters, ovens, hot water systems, dryers, pumps, and some power tools can all drain generator capacity quickly.

Smaller essentials like lights, laptops, phone chargers, fans, and internet modems are much easier to manage.

During a blackout, the smartest approach is to prioritise what matters most: keeping food cold, lights on, medical gear running, communication available, and basic comfort covered.

Always allow for both running watts and starting watts, especially with fridges, pumps, air conditioners, and motor-driven appliances. Do that, and you will get more from your generator, reduce the risk of overload, and keep your household running more smoothly when the grid goes down.

For a simple next step, compare home backup generators or use the generator sizing tool to find a suitable option for your appliances.