What Size Generator Will Run a House?
A 5kVA generator runs a house's essentials and a 10kVA runs most of it, big aircon aside. That's what size generator to power a house, and your inlet matters as much as the badge on generators. Here's the working.
Whether you can run a generator into your house at all, and how that works in Australia, is covered in using a generator to power your house. This guide is about size. For camping, caravans and worksites, see the generator size guide.
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Take the quiz!House Generator Size in kVA and kW
kVA Badges and Real kW
Most generators here are sold on kVA. Gentech lists its EP models at a 0.8 power factor, so each kVA gives you about 0.8kW. A 10kVA badge means about 8kW, which is exactly what Hyundai lists for its HY10000LEK.
Inverters and some open frames are named after their peak instead. The Westinghouse WHXC5000 wears a 5kVA badge and runs at 4,000W. Size your house against the running figure, because that's what the generator holds all day.
Running Watts Plus the Biggest Start-Up
List what you want on at the same time and add up their running watts. Then add the start-up surge of the single biggest motor, usually a fridge or the aircon.
Queensland's Electrical Safety Office gives typical figures. A fridge or freezer runs on about 180W and needs about 1,800W to start. A large split system runs on 6,000W and can need up to 30,000W to start.
Generator Sizes for a House: 3kW, 5kVA and 10kW
| House setup | Running load | Biggest start-up | Generator needs |
|---|---|---|---|
| Essentials: fridge, freezer, TV, five globes | 1,040W | 1,800W (fridge) | 2,840W |
| Essentials plus a microwave | 3,040W | 1,800W (fridge) | 4,840W |
| Most of the house: two fridges, ten globes, TV, microwave, coffee maker, frypan | 7,240W | 1,800W (fridge) | 9,040W |
| Most of the house plus a large split system | 13,240W | 30,000W (aircon) | 43,240W |
These use the Queensland regulator's typical figures, taking each appliance at the top of its range. Your appliance plates will differ, so run your own numbers the same way.
3kW Generator for House Essentials
A 3kW generator runs a house's essentials: the fridge, a freezer, the TV and lights. The table puts that at 2,840W with a compressor starting. A unit running at 3,000W with a 3,500W peak, like the Hyundai HY3500i, has room.
The microwave is the stretch. With a fridge compressor starting at the same moment, the figures put you past that 3,500W peak, so keep cooking short and switch the TV off while you do it.
Owners make small units work. A poster on Whirlpool powered their home for several days on a Honda EU22, a 2kVA inverter.
5kVA Generators and the 15A Inlet
Most plug-in home setups run through a 15A inlet and lead, and the same Whirlpool thread puts that limit at about 3.6kW. A 5kVA generator running at 4,000W already covers everything a 15A connection can pass.
That thread's advice for a load of about 3kW over long periods was a generator with 4kW or more of continuous output, not one working near its maximum. That's the case for 5kVA over 3kW when the essentials run all day. Browse generators for home.
10kW Generator for Most of a House
A 10kW generator is enough for most of a house. The busy evening in the table needs 9,040W with a compressor starting, which 10kW of running output covers.
A 10kVA badge only gives you about 8kW, though, and that same evening goes a touch past it. Leave the frypan off and it fits.
A 10kVA does suit a 32A inlet, which carries about 7.4kW at 230V. The HY10000LEK makes 8kW, has a 32A socket and costs $1,679.70. The diesel Hyundai DHY10000SE-LRS is rated at 7,250W with a 32A outlet, for longer runs. See the 10kW generators.
What no 10kW unit does is start a large split system. On the Queensland figures, that can take 30,000W.
Running a House Permanently on a Generator
You can run a house on a generator full time, but it's a different job to riding out a blackout. Ratings, fuel and servicing all change.
Prime and Standby Ratings
Backup generators often carry a standby rating as well as a prime one. The Hyundai DHY12000XSEM-RS lists 8,000W standby and 7,250W prime, and its listing says the prime figure is what it runs continuously. Size permanent power against the prime number.
Fuel, Warranty Hours and Wet Stacking
Fuel is the big cost. Our fuel consumption figures put the DHY10000SE-LRS at 3.57 litres of diesel an hour at 75% load. That's about $213 a day at early September 2026 prices.
Warranty hours go quickly too. Both Hyundai diesels above carry 12 months or 500 hours, and 500 hours of round-the-clock running is about 21 days.
Don't oversize to be safe, either. Caterpillar says running a diesel generator below 30% of its rated output for long periods causes wet stacking. After light running, it recommends at least 30% load for about 30 minutes in every four hours. Size close to your real load.
Changeover Switch and Permanent Connection
A generator wired into the house needs a licensed electrician and a permanently wired changeover switch. Queensland's regulator says the install must meet AS/NZS 3000 and AS/NZS 3010, and the switch stops dangerous backfeeding.
Run it outside only. Energy Safe Victoria warns that a generator indoors or in an enclosed space can cause carbon monoxide poisoning very quickly.
For most houses, 5kVA covers the essentials through a 15A inlet, and 10kVA covers most of the house through a 32A inlet. Which one's for you? Tell us what you want running and we'll size it with you. Ring the store on 03 7056 6732, text 0476 330 590, or try the generator finder.
