Home Backup Guide
When the power goes out, a generator can keep the essentials running and help keep your home comfortable, connected and secure.
But choosing a home backup generator isn't simply about buying the biggest model you can afford. A larger generator will usually cost more, use more fuel and take up more space. The better approach is to work out what you actually need to power and choose a generator with enough capacity to handle it.
From calculating your wattage requirements to choosing between petrol, diesel, dual fuel and inverter generators, this guide covers what to look for when choosing a home backup generator.
What Is a Home Backup Generator?
A home backup generator provides an alternative source of electricity when your mains power isn't available.
Depending on the generator you choose and how it is installed, you can use it to power individual appliances and essential equipment, or supply selected circuits within your home.
For many households, the most practical solution is to focus on the essentials rather than trying to power everything at once.
These could include:
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Fridge or freezer
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Boiler or heating controls
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Lighting
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Wi-Fi router
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Television
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Computers and essential electronics
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Security systems
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Medical equipment
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Selected kitchen appliances
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Sump pumps or other essential pumps
Exactly what you need to keep running will depend on your home and your priorities during a power cut.
Step 1: Decide What You Need to Power
Before choosing your generator, make a list of the appliances and equipment you want to keep running during a power cut.
It's important not to simply add together the wattage printed on each appliance. Some equipment, particularly anything with a motor or compressor, can need considerably more power when starting than it uses once running.
Fridges, freezers, pumps and some heating equipment are common examples.
When sizing your generator, you therefore need to consider both running watts and starting watts.
Essential Loads vs Non-Essential Loads
You may find that you don't need to power everything in your home during an outage.
For example:
| Appliance Priority | Requirement |
|---|---|
| Fridge/freezer | Essential |
| Lighting | Essential |
| Wi-Fi router | Essential |
| Heating controls | Essential |
| Security system | Essential |
| TV | Useful |
| Laptop | Useful |
| Microwave | Useful |
| Kettle | Useful |
| Washing machine | Non-essential |
| Tumble dryer | Non-essential |
| Electric oven | Non-essential |
| Electric shower | Usually high-demand |
Prioritising your essential loads can significantly reduce the generator capacity you need.
How Much Power Do You Need?
Once you've decided what you want to run, you can start working out your total wattage requirement.
For example, if you wanted to run:
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Fridge/freezer – 200W running
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Lights – 100W
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Wi-Fi router – 20W
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TV – 100W
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Laptop – 60W
Your normal running requirement would be around 480W.
However, you'll still need to account for the additional starting power required by appliances such as the fridge/freezer.
It's also worth thinking about which appliances you'll actually use at the same time. You don't necessarily need enough generator capacity to run every appliance simultaneously if you can manage when higher-demand appliances are switched on.
Tip: Use your appliance ratings or a generator wattage calculator to get a realistic idea of how much power you'll need before choosing your generator.
Use our Wattage Calculator to estimate the generator size you need.
Don't Automatically Buy the Biggest Generator
When it comes to generators, bigger isn't always better.
A generator that's considerably larger than you need will generally cost more to buy, take up more storage space and use more fuel.
Instead, look for a generator that can comfortably handle your expected load, including the starting requirements of your appliances.
You should also avoid regularly operating a generator at or beyond its rated capacity. Make sure the generator is correctly sized for the equipment you're powering and that any connection to your home's electrical system is properly designed and installed.
What Type of Generator Should You Choose?
Once you've worked out how much power you need, the next step is choosing the right type of generator.
Different generator types offer different benefits, so consider how you'll use yours, where it will be positioned and how long you expect it to run.
Inverter Generators
Inverter generators are a popular choice for home backup where portability, quieter operation and clean power are important.
They produce a stable electrical output, making them well suited to modern electronics and sensitive equipment.
They're also often more compact than traditional frame generators, making them easier to store when they're not in use.
Good for:
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Smaller essential loads
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Electronics
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Home offices
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Portable backup power
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Quieter environments
Conventional Generators
Traditional open-frame generators can provide substantial power and are a practical choice when higher output is the priority.
They're generally less focused on portability and quiet operation than inverter models, but can offer a straightforward solution for larger power requirements.
Good for:
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Larger loads
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Extended backup use
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Workshops and worksites
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Situations where portability and low noise aren't the main priorities
Dual-Fuel Generators
Dual-fuel generators give you the flexibility to run your generator using two fuel sources, typically petrol and LPG.
Having two fuel options can be particularly useful when preparing for a power cut, giving you greater flexibility if one fuel isn't readily available.
LPG can also be convenient for longer-term storage, while petrol is widely available and can be useful when you need a readily accessible fuel source.
Good for:
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Emergency preparedness
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Longer backup periods
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Greater fuel flexibility
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Homes that don't want to rely solely on petrol
Diesel Generators
Diesel generators are a good option when you need reliable backup power for longer periods or have higher power requirements.
Diesel engines are well suited to sustained operation and demanding applications, which is why they're commonly used for commercial, industrial and larger backup power systems. For homes with significant electrical requirements, they can also provide dependable power during extended outages.
Diesel generators are a good choice for:
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Larger homes with higher power requirements
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Extended power outages
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Regular or frequent generator use
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Applications where durability and long-term operation are important
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Higher-power backup systems
However, diesel isn't necessarily the best choice for every home.
Diesel generators are typically larger and heavier than many petrol or inverter models, and can also be more expensive. They may produce more noise and vibration too.
If you only need to keep a few essential appliances running during an occasional power cut, a smaller petrol or inverter generator could be a more practical option.
Consider diesel if: you need higher power, expect longer running times or want a generator designed for demanding, regular use.
Consider another option if: portability, low noise, compact storage or a lower purchase price are more important to you.
What Features Should You Look For?
Once you've narrowed down the generator type and required wattage, there are a few features worth considering.
Electric Start
Electric start makes getting your generator running quick and convenient, particularly when you need backup power in a hurry.
Some generators also include recoil starting as a backup.
Automatic Voltage Regulation
AVR helps regulate the generator's electrical output and can be useful when powering a range of household equipment.
Low Oil Shutdown
Low-oil shutdown can automatically stop the engine if the oil level becomes too low, helping protect the engine from damage.
CO Shutdown
Carbon monoxide protection can provide an additional safety feature on compatible generators.
However, it should never be considered a replacement for safe generator placement.
Petrol generators produce carbon monoxide and should never be operated indoors or in enclosed spaces. Always position your generator outdoors in a well-ventilated area where exhaust fumes can disperse safely and cannot enter your home.
Remote Start
Remote start can be particularly useful if your generator is positioned outside and you don't want to go outside to start it.
Wheel Kit
Larger generators can be heavy, so wheels and a suitable frame can make moving the generator around your property much easier.
Multiple Fuel Options
If you're preparing for longer power cuts, dual-fuel capability can give you greater flexibility over which fuel you use.
What You Probably Don't Need
It's easy to get caught up in specifications and features that sound impressive but don't necessarily make sense for your home.
You probably don't need:
A Huge Generator
If your main priority is keeping the fridge, lights, Wi-Fi and a few essential appliances running, you may not need a generator capable of powering your entire house.
Every Appliance Running at Once
There's usually no need to run your oven, washing machine, kettle, tumble dryer, TV and everything else at the same time.
Prioritising your essential loads can reduce the generator size you need.
Excessive Portability
If your generator will stay in one designated location, an ultra-portable design may not be particularly important.
Features You'll Never Use
Electric start, remote start and dual-fuel capability can all be useful features, but think about how you'll actually use your generator before paying extra for something you don't need.
What Should You Avoid?
There are a few things you should pay particular attention to when choosing and using a home backup generator.
Don't Choose Based on Peak Watts Alone
Peak or starting watts can make a generator appear more powerful than it is during continuous operation.
Always look at the rated/running wattage as well as the maximum or starting wattage when comparing generators.
Don't Constantly Overload Your Generator
Regularly exceeding a generator's rated capacity can put unnecessary strain on the engine and electrical system.
It's better to leave yourself some headroom rather than choosing a generator that's only just powerful enough for your calculated load.
Never Run a Generator Indoors
This is one of the most important safety rules.
Never run a petrol, diesel or other combustion-engine generator inside your home, garage, shed or another enclosed space.
Carbon monoxide is colourless and odourless and can build up to dangerous levels quickly.
Your generator should be positioned outdoors, away from doors, windows and other openings, with exhaust fumes able to disperse safely.
Never Connect a Generator Directly to a Wall Socket
Never attempt to power your home's electrical system by plugging a generator into a normal household socket.
If you want your generator to supply household circuits, the installation must be correctly designed and connected using the appropriate equipment and isolation arrangements.
Speak to a qualified electrician about connecting a generator to your home's electrical system.
Incorrect connections can create serious electrical hazards and may energise circuits that are assumed to be switched off.
Do You Need a Transfer Switch?
If you're only powering individual appliances directly from a portable generator, you may not need a permanent transfer switch.
However, if you want your generator to supply selected circuits within your home, a properly installed transfer or changeover arrangement can provide a safer and more convenient solution.
This separates the generator supply from the mains supply rather than relying on improvised connections.
For a permanently connected home backup system, speak to a qualified electrician about the right installation for your property.
What About a Whole-Home Generator?
A whole-home backup system is designed to provide considerably more power and can potentially supply a much larger number of household circuits.
This can be useful for larger homes or households where keeping more equipment running during a power cut is important.
However, a whole-home system also means:
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Higher generator capacity
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Greater fuel consumption
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More installation requirements
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More space required
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Higher purchase and installation costs
For many homes, a smaller generator supplying the essentials can provide a better balance between cost and capability.
Petrol vs Dual Fuel: Which Is Better?
There's no single answer that works for every home.
Petrol is convenient, widely available and suitable for many portable generators.
Dual fuel gives you the added flexibility of switching between petrol and LPG depending on availability and your requirements.
If you're preparing for longer or unexpected power cuts, having more than one fuel option can be a useful advantage.
Whichever fuel you choose, make sure it is stored safely and in accordance with the manufacturer's instructions and relevant local requirements.
Think About Noise
Generator noise is another important consideration, particularly if you live in a residential area.
An appropriately sized generator won't need to work harder than necessary, and an inverter generator can be a particularly good choice where quieter operation is important.
Check the generator's stated noise level before buying, but remember that actual noise can vary depending on the load, operating conditions and where the generator is positioned.
Think About Fuel Consumption
Generator capacity isn't the only specification worth considering.
Two generators with similar power outputs can have different fuel consumption, so think about how long you'll need your generator to run and how much fuel you'll need during an extended power cut.
For emergency backup, fuel efficiency can make a noticeable difference over several hours or days of operation.
Don't Forget Maintenance
A generator that's been sitting unused for months still needs to be ready when you need it.
Regular maintenance should include checking:
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Engine oil
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Fuel condition
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Air filter
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Spark plug
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Battery, where fitted
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Fuel lines and connections
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General condition of the generator
If you only use your generator during emergencies, periodically running it in accordance with the manufacturer's instructions can help make sure it starts and operates correctly when you need it.
Always follow the maintenance schedule provided for your specific model.
Home Backup Generator Checklist
Before choosing your generator, ask yourself:
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What do I actually need to keep running?
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How many watts do those appliances require?
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What are their starting watt requirements?
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Which appliances need to run at the same time?
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Do I need portable or fixed backup power?
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Would an inverter generator suit my requirements?
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Would dual fuel give me useful flexibility?
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How important is low noise?
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How long might I need to run the generator?
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How much fuel can I safely store?
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Where will I operate and store the generator?
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Do I need a transfer or changeover system?
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Will I need an electrician to connect it to my home's circuits?
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What maintenance will the generator require?
The Bottom Line
Choosing a home backup generator doesn't have to be complicated.
Start with the basics: what do you need to keep running when the power goes out?
Work out your running and starting wattage, prioritise your essential appliances and choose a generator that comfortably meets those requirements.
Don't automatically go for the biggest generator available. Consider fuel consumption, noise, portability, fuel type, safety features and how you'll actually use the generator.
Most importantly, think about safe operation and installation from the beginning. A generator is designed to provide reliable backup power, but it needs to be correctly selected, positioned and operated to do its job safely.
With the right generator and a little preparation, you'll be ready to keep the essentials running when the mains power goes down.