Power outages from natural disasters can be an enormous hassle in Australia. In just the last 12 months, there have been extended power outages lasting multiple days in Queensland, NSW, Victoria and Tasmania. So to help you plan for your energy security, in this post we’re going to look at the generator type you need to provide electricity at home in an emergency situation.

What is a home generator?

A home generator is a machine or device for conversion of mechanical power into electrical power to use in the appliances and devices connected to your home. Generators are dispatchable (the energy can be delivered on demand) allowing a software system to start them up whenever required.

Home generators are standalone machines used to provide electric power when it is not available from the grid such as in a natural disaster, weather event or power outage.

Home generators are becoming popular

Australia is prone to natural hazards. And as our natural disasters intensify, more Australians are asking and will ask themselves the question ‘What generator do I need to run a house?”.

You see, more intense disasters lead to larger scale blackouts, which cause longer power outage timeframes. It takes time for power networks to reconnect thousands of home to the power grid.

And more frequent bad weather events bring the possibility of the power going out more often.

Power is an essential service because without it, we struggle in our day to day lives. So when natural disasters are cause us to lose power, of course Australians are asking themselves: should I invest in a home generator? And what generator do I need?

What generator do I need to run a house?

The answer is, you need a home generator that is powerful enough to meet your specific household power requirements.

Your power requirements will be different based on whether you just want critical backup power for a few home appliances (minimal power), or whether you want to power your entire home (needing a lot of power).

Your power requirements will determine the size of generator you need. The size of generator you need will help decide the type of generator to buy.

Sounds complicated, but don’t worry. It’s not! We’re going to step you through it below.

What size generator do I need to run a house?

A home generator is typically powered by diesel, petrol, natural gas, or solar battery. Each generator is sized according to the amount of power it can generate.

The size of a home generator is determined by the rating of the generator. For example, a 5,000-watt size generator can provide enough power to operate several large appliances, including a refrigerator, and a water heater.

A 10,000-watt size generator can provide enough power to operate many of the appliances in a home. The size of the generator you need will depend on the number and type of appliances you want to power during an outage.

Sometimes generators are sized in kVA or kilovolt amperes. This is a different unit of measure. You can convert kVa into watts to work out whether the generator is powerful enough to run your appliances.

Understanding starting, running and surge wattage

Before you understand how much backup power you need, it’s important to understand how much power your appliances use. To do this, you need to be familiar with starting, running and surge wattage. All of these help determine your generator power requirements.

• ‘Running watts’ indicate how much power the appliance needs to run continuously at full power.
• ‘Starting watts’ show how much power is required to start the appliance. Some appliances need more power to start them up than to run them.
• Surge wattage is similar to starting watts.

You can read more about starting, running and surge wattage in our Generator Sizing Guide.

How much generator power do you need?

This question is a function of what size and what type of appliance you want to power. It’s a common question but not a difficult one. We can work this out in 4 easy steps. Let’s get to it.

1. list the appliances you want to run
2. calculate starting and running wattage
3. total up your watts to see how much generator power you need
4. Covert your watts to kVa.

Let’s explain each step.

What are your home power requirements?

The first thing to think about is, how much power will you want or need if a natural disaster or emergency causes mass electric grid outages?

Put yourself in one of these three categories:

1. Critical equipment or non-discretionary load – Your fridge, oven, hot water, lighting circuits and the internet.
2. Critical equipment plus some discretionary load – All of the above plus your washing machine, TV and computers
3. Whole house power supply – Everything in your home. Includes large load like a electric water heater or an air conditioner.

Decide which group you’re in. Remember, the more appliances you need to power the higher your generator purchase and running costs will be.

List the appliances you want to run

Make a list of all the appliances you want to run and write down the starting and running wattage for each appliance. These numbers are usually stamped on the appliance nameplate (e.g. you’ll see 1200W written on the plate) or you can find them in the user manual. If you can’t find them, use Google to search for the model number and name.

Calculate starting wattage and running wattage

Add up all of the running watts for your list of household appliances. This list of total running wattage will help tell you the total power needs for your generator.

Add the highest starting wattage number on your list to your total running wattage.

Add some extra watts to your totals so you come up with a generator size that can accommodate for surge wattage.

How much generator power do you need?

Find a home generator that is rated with a ‘peak power’ output that is larger than your power requirements, from your calculations.

The generator’s ‘rated output’ needs to be higher than your ‘total running watts’.

The generator ‘rating’ is just the threshold for how many appliances (watts) it can run at one time (‘peak power’ output), and how much power it can produce continuously over a long time (‘rated output’).

If you need help with this, we have a free, downloadable Generator Sizing Calculator you can use.

Now you have an idea of the right size generator to give you enough power, you can work out what type of unit you will need.

Types of home generators

There are a few different types of home generator on the market, and each has its own advantages and disadvantages. Here’s a quick rundown of the most popular options:

1. Portable generator.

A smaller generator and can be easily moved around, making them ideal for powering small appliances or electronics in an emergency situation.

2. Standby generators / whole home generator.

A larger generator that is more powerful than portable generators, and can be used to power an entire house in extended blackouts or brownouts.

3. Inverter generators.

These are similar size generator to portable units, but they’re more efficient and produce cleaner power ideal for powering sensitive electronics. However, they’re generally not as powerful as standby generators and can’t be used to run large appliances.

4. Solar generators.

These rely on solar panels to convert sunlight into electricity, as well as battery storage. They’re environmentally friendly to run, and can be used even in remote areas where there’s no access to the electric grid.

Let’s look at each in more detail to help you decide.

5. Portable generators

A portable generator is one you can plug appliances straight into and move around as needed. Small camping generators are an example of a portable generator and can suffice for backup power to your most critical household equipment.

Nowadays, a these generators can also provide more power than you might think, with a large portable generator rated at 4000 + watts (4kW).

A generator this big could theoretically run multiple home appliances. Whether you can use portable size generator will depend on your power requirements, as well as total running wattage and starting watts.

If you only want to power essential equipment and don’t want to run any large appliances like a water heater, you may be able to find the right size generator in this category.

Whole home generator

A whole home generator is a conventional heavy duty generators with more wattage. Units with a total wattage of 10kW or 20kW will be standby generators. They run on diesel generally but you can also buy ones that run on natural gas. A bigger home generator can provide power to more things, like electrical tools, electric motors, as well as household appliances.

You will not need this big of a generator if you’re looking to power essential appliances. If you are looking to power an air conditioner, plus lighting circuits, plus your fridge, freezer, oven, and TV then all these appliances will need standby generator.

Inverter generators

Inverter generators are a small size generator known for being quiet and running cooler than the conventional types.

It is possible to run your house with an inverter generator, if the generator size is adequate to meet your needs. But this type of generator is generally not as big as standby generators so may not be adequate to meet your running wattage or starting wattage needs.

Solar generator

A solar generator is quiet, efficient, and easy to use and standard models can power essential appliances like refrigerators and freezers, as well as lights and communication devices. They’re also extremely popular in Australia.

Solar generators come in both fixed and portable models. Fixed solar is also called ‘rooftop solar’. It’s prevalent in Australia. A portable solar generator is also called a portable power station. These use smaller portable solar panels and smaller batteries. But can be linked together to boost power output. Portable power stations these days can even power your house!

Most people think that having a rooftop solar system will give you power when the grid goes down. This is not the case. In Australia solar generators connected to the power grid and your home are installed with an isolator.

An isolator is a switch that disconnects the solar generator from the power grid. In a power outage, the isolator will stop the solar generator providing power to the grid. It will also protect the solar generator from being damaged by voltage surges.

To provide backup power during an extended power outage, the solar generator will need to be wired by an electrician for ‘uninterrupted power supply’ (UPS). Solar panels don’t store power so a solar generator will also need a backup power source, such as a battery.

What home generator do I need to power sensitive electronics?

Some appliances and modern electronics are more sensitive to the quality of power supply and any changes in it. Plasma TVs, LCD TVs, computers and even some NBN boxes are examples.

An inverter generator or one with Automatic Voltage Regulators will not harm these electronics.

An Automatic Voltage Regulator is a device that is added to a portable or standby generator to smooth out load, resulting in higher consistent power. Some generators come standard with these systems, allowing them to produce clean energy without being inverter generators.

Installation of your generator

You must have an electrician install a standby generator via a transfer switch.

Don’t be tempted by online forums recommending you plug your generator into a wall outlet as a cheap way to run power your home. It’s dangerous, can void your home insurance, and leave you exposed to criminal prosecution.

A transfer switch disconnects the generator from the power grid when the grid is restored. It keeps the generator’s power from back-feeding into the grid which can be dangerous

When the generator is switched on, the switch disconnects power from the home’s electrical grid and allows it to be supplied only to the generator. Many large appliances are connected straight to your board so you cannot connect them into the generator extension cord.

Conclusion

In this post we’ve helped answer the question: Wwhat generator do I need to power a house?’, both in terms of size and type of unit. The answer is you need a generator that is the right size and type to meet your specific power needs.

The size you calculate will help determine what type of unit you need.

If you’re looking for a home generator to power a whole house with air conditioner in an emergency power outage, then a standby generator is going to be the best generator. You’re look at 10 kW to 20 kW of power.

However, if you’re only looking to power a few portable appliances or electronics in an emergency situation, then a portable option might be the right sized generator. A 7.5 kW unit may be sufficient.

FAQ

1. What size generator do I need for a 3 bedroom house?
2. What size generator to run a 2,000 sq ft house?
3. What size generator to run a 1,500 sq ft house?

The size home generator you need for a 3 bedroom house / 2,000 sq ft house depends more on your power requirements than on the size of your home.

If you want back up power for just a few appliances 5kW (5,000 watts) of power may be sufficient.

If you want a generator to power a typical 3 bedroom home, you may need more than 10kW (10,000 watts).

If you want to power all appliances plus air conditioners, you are looking at power needs closer to 20kW.

4. Will a 12,000 watt generator run a house?

Yes a 12,000 watt generator will run a house. It may not run all of your appliances however. Air conditioners and water heaters can use a large amount of start and run wattage. If you want to power this type of appliance, you may need a larger size generator