What Size Generator Do You Need to Power a House?
Most houses require a generator between 5kW and 20kW, depending on whether only essential appliances or the entire home needs power. Generator size is determined by total running load, startup load, and how many appliances operate at the same time. A professional assessment ensures safe, reliable operation during power outages.
How Generator Sizing Works for Residential Properties
Choosing the correct generator size is critical for safety, reliability, and long-term performance. Undersized generators struggle under load, while oversized generators can operate inefficiently and suffer unnecessary wear.
Two key factors must be considered:
Running load – the power required once appliances are operating
Startup load – the extra power required when motors start
Appliances such as air conditioners, refrigerators, and water pumps often require significantly higher startup power.
Typical Generator Sizes for Homes
Household Requirements and Recommended Generator Size
Essential circuits only – 5-7kW
Essentials + small air conditioning – 7-10kW
Multiple appliances – 10-15kW
Whole-house backup – 15-20kW
Why Correct Sizing and Servicing Matter
A correctly sized generator must also be properly maintained to deliver its rated output. Regular servicing ensures:
Stable voltage under load
Fuel efficiency
Safe operation during extended outages
What size generator is needed to power a house?
Most houses require a generator between 5kW and 20kW depending on how many appliances need to run at once. Essentials-only setups require smaller generators, while whole-house systems require larger capacity units.
Why does generator sizing matter?
Correct generator sizing prevents overloads, improves efficiency, and ensures reliable power delivery during outages. Incorrect sizing can lead to equipment damage or generator failure.
If you’re located in Brisbane, the Gold Coast, Toowoomba, or the Northern Rivers and require reliable generator servicing or repairs, Equipment Services and Machinery provides professional inspection, maintenance, and ongoing support. Phone 07 3607 3311 for enquiries.
