What Size Generator Do I Need? NZ Sizing Guide
The most common question we get, and the honest answer is: it depends on what you're running, and how much extra it pulls when it switches on. Here's how to get it right.
1. Add up your running watts
Every appliance has a running wattage, the power it uses once it's going. List everything you'll run at once and add them up. Here are typical figures:
| Appliance | Running watts | Start-up surge |
|---|---|---|
| LED / string lighting | ~300 W | None |
| Phone & EFTPOS | ~150 W | None |
| Fridge / chiller | ~350 W | 2 to 3x |
| Chest freezer | ~400 W | 2 to 3x |
| Coffee machine | ~1,600 W | Low |
| Bain-marie / food warmer | ~1,500 W | None |
| Deep fryer (electric) | ~2,400 W | None |
| Power tools | ~1,400 W | 2x |
| Air compressor | ~1,800 W | 3x |
| Water pump | ~1,200 W | 3x |
| Site flood lights | ~1,000 W | None |
| PA / sound system | ~800 W | Low |
| Patio / space heater | ~2,000 W | None |
2. Allow for start-up surge, the bit people miss
Anything with a motor or compressor (fridges, freezers, pumps, compressors) briefly pulls 2–3× its running watts when it starts. Size for the running total plus the biggest single start-up surge, or it'll trip out.
3. Add headroom
Never run flat out. Add ~20% headroom so the generator runs cool and copes with surprises. Our size calculator does all three steps automatically.
4. kVA vs kW
kVA is total power available; kW is what your gear actually uses. Rough rule: kW ≈ kVA × 0.8.
Typical picks from our fleet
- Honda EU22i (2.2 kVA), stall, coffee cart, small wedding, lights + EFTPOS.
- Honda EU32i (3.2 kVA), busier stall or small food truck.
- Honda EU70is (7 kVA), full food truck, trades, larger events.
- Denyo 60 kVA diesel, construction, three-phase, standby, big events.
FAQs
What size generator for a coffee cart?
A single espresso machine needs ~1500–2000 W running but surges higher on start-up. A EU22i (2.2 kVA) suits a simple cart; add a grinder, fridge and lights and step up to the EU32i (3.2 kVA).
What size generator for a wedding?
Depends on catering and lighting. A quiet inverter suits many marquees; larger receptions with electric catering may want the 60 kVA diesel. See our wedding page or use the calculator.
Need power sorted?
Tell us the job, we'll recommend the right unit and get you a price fast.