Quick Answer
For a typical Melbourne home, a 5–8 kVA generator covers essentials (fridge, lights, one air conditioner, phone charging and a TV). To power a whole house including electric hot water and multiple air conditioners, you need 15–20 kVA or more. The most important step is listing your critical appliances, adding up their wattage, and sizing to 80% of the generator’s rated output to avoid overloading. Generators cost from $500 for a portable unit to $8,000+ for a whole-home standby system.
Generator sales spike in south-eastern Melbourne every time a major storm or bushfire event causes widespread power outages across Casey, Cardinia, Frankston and the Mornington Peninsula. The Dandenong Ranges and Mornington Peninsula in particular experience multi-day outages several times per decade, making backup power a genuine household planning consideration.
The most common mistake homeowners make is buying a generator that’s too small (overloaded and at risk of damage) or too large (expensive, heavy, and inefficient at low loads). This guide helps you size correctly from the start.
Step 1: List the Appliances You Want to Power
Before choosing a generator size, make a list of the appliances you want to run during an outage. Every appliance has two wattage figures that matter:
- Running watts — the power it draws continuously while operating
- Starting watts (surge watts) — the brief spike of power required to start motors (refrigerators, air conditioners, pumps). This can be 2–3x the running wattage.
Your generator must handle the running load of everything switched on simultaneously, plus the highest single starting surge you expect at any given moment.
| Appliance | Running Watts (approx) | Starting Watts (approx) |
|---|---|---|
| Refrigerator (400L side-by-side) | 150–200W | 600–1,000W |
| Chest freezer | 100–150W | 400–600W |
| Split system air conditioner (2.5kW) | 600–900W | 1,500–2,500W |
| Split system air conditioner (7.1kW) | 2,000–2,500W | 4,000–6,000W |
| LED lights (10 × 10W) | 100W | 100W (no surge) |
| Laptop and phone chargers (x4) | 100–200W | 100–200W |
| TV (65″ LED) | 100–150W | 150W |
| Microwave (1,000W) | 1,000W | 1,200W |
| Kettle (2,400W) | 2,400W | 2,400W |
| Electric hot water system | 3,600–4,800W | 3,600–4,800W |
| Sump pump (for flooding) | 400–800W | 1,200–2,000W |
| CPAP machine | 30–60W | 30–60W |
| Pool pump (0.75kW) | 750W | 1,500–2,000W |
Step 2: Calculate Your Total Load
Add up the running watts of everything you want to run simultaneously. Then identify the appliance with the highest starting surge — this is usually an air conditioner or refrigerator. Add the surge watts for that single appliance to your total running load. The result is your minimum generator requirement.
Example — Melbourne family essentials kit (no air con):
- Refrigerator running: 200W + surge of 800W = needs to handle 1,000W peak
- Lights (8 × LED): 80W
- TV + laptop + phones: 250W
- Microwave (occasional): 1,000W
- Total running load: ~530W; peak with microwave + fridge surge: ~2,200W
- Minimum generator: 3 kVA
Example — Melbourne home with one air conditioner (2.5kW cooling split system):
- Air conditioner running: 800W + surge of 2,000W
- Refrigerator running: 200W
- Lights and devices: 300W
- Total running load: ~1,300W; peak with air con surge: ~3,300W
- Minimum generator: 5 kVA (size to 80% of rated output)
Step 3: Choose Your Generator Size
| Generator Size | What It Powers | Typical Cost (2026) | Best For |
|---|---|---|---|
| 2–3 kVA | Fridge, lights, phone charging, small TV | $500–$900 | Weekend camping or very basic outage cover |
| 4–5 kVA | Above + one small air con (2.5kW) or microwave | $900–$1,800 | Most Melbourne homes — essentials only |
| 6–8 kVA | Above + second air con or power tools | $1,800–$3,500 | Larger homes; tradespeople; farm use |
| 10–12 kVA | Most of the house, including larger A/C systems | $3,500–$5,500 | Large homes; home offices; extended outages |
| 15–20 kVA | Whole home including electric hot water | $5,000–$10,000 | Full home backup; rural properties |
| Inverter generator (2–4 kVA) | Sensitive electronics, laptops, medical devices | $700–$2,200 | Quiet, fuel-efficient; for CPAP or electronics |
Open Frame vs Inverter Generators
There are two main generator types available at most hardware stores:
Open Frame (Conventional) Generators
These are the traditional red or orange units with an exposed engine frame. They’re louder (65–75 dB), heavier, and produce power that fluctuates slightly with load. They’re reliable, cost-effective and good for running tools, pumps and appliances that aren’t sensitive to voltage variation. Brands: Honda, Yamaha, Gentech, Pramac, Westinghouse.
Inverter Generators
Inverter generators produce “clean” sine wave power — stable voltage regardless of load variation. They’re significantly quieter (50–60 dB), more fuel-efficient at partial load, and safer for sensitive electronics (laptops, CPAP machines, smart TVs). They’re more expensive for the same wattage. Recommended for home use where electronics are a priority. Brands: Honda EU series, Yamaha EF series, EF Power inverter range from Total Tools.
Fuel Types and Dual-Fuel Options
| Fuel Type | Pros | Cons | Notes |
|---|---|---|---|
| Petrol | Widely available; most common generator type | Short shelf life (3–6 months); fire risk for storage | Store with fuel stabiliser; use ethanol-blend fuel (E10) with caution |
| LPG (gas) | Long shelf life; cleaner burning | Less energy-dense than petrol; LPG cylinders need storage space | Good for rural properties with existing LPG supply |
| Dual-fuel (petrol + LPG) | Flexibility; can switch fuel mid-outage | Slightly more complex; more expensive | Good choice for extended outage preparedness |
| Diesel | More efficient; better for continuous use; longer engine life | More expensive upfront; heavy; not for occasional use | Best for large (10 kVA+) standby installations |
Connecting a Generator to Your Home
There are two safe ways to connect a generator to household circuits:
- Portable use (extension leads): Plug appliances directly into the generator using heavy-duty 10A or 15A extension leads rated for outdoor use. This is safe, requires no installation, and is suitable for occasional outage use.
- Transfer switch (licensed install): A licensed electrician installs a manual or automatic transfer switch at your switchboard. This allows selected circuits to switch between mains power and generator safely. Cost: $600–$1,500 for manual changeover; $1,500–$4,000 for automatic transfer switch.
Storing Fuel Safely in Melbourne
Petrol storage is regulated in Victoria by the Dangerous Goods (Storage and Handling) Regulations 2012. For domestic storage:
- Maximum 250 litres of flammable liquid at residential premises without a dangerous goods licence
- Store in approved metal or plastic containers (AS/NZS 2906 compliant) — not repurposed food containers
- Store in a cool, ventilated area away from ignition sources
- Use ethanol-free petrol where possible for long-term storage — ethanol absorbs moisture and degrades fuel quality
- Add a fuel stabiliser (STA-BIL or similar) if storing for more than 30 days
Top 10 Tips and Gotchas
- Never run a generator indoors or in a garage. Petrol generators produce carbon monoxide (CO) — a colourless, odourless gas that is lethal in enclosed spaces. Always operate in the open air, at least 1 metre from windows and doors.
- Size to 80% of rated output. Running a generator at 100% load reduces engine life and increases the risk of overload trips. A 6 kVA generator is ideally loaded to no more than 4.8 kW.
- Start large appliances one at a time. Start the fridge first, let it stabilise, then start the air conditioner. Simultaneous starting surges can overload a correctly-sized generator.
- Service the generator annually. Change the oil, replace the spark plug, and run it under load for 30 minutes every 3–6 months. A generator that hasn’t run in two years often won’t start when you need it.
- Melbourne storm season peaks November–March. Buy and service your generator before the October–November bushfire and storm season begins — generator stock at Bunnings and Total Tools sells out quickly after major weather events.
- Consider fuel consumption carefully. A 6 kVA open-frame generator uses approximately 2–3 litres of petrol per hour at 50% load. A 72-hour outage requires 150–200 litres — more than most households can safely store.
- Medical devices need inverter power. CPAP machines, home nebulisers and some medical pumps require clean sine wave power. Only an inverter generator (or a UPS system) is suitable — never use an open-frame generator for medical devices without verification from the device manufacturer.
- Check council noise restrictions. Most Melbourne councils have noise regulations that apply to generators operating late at night. In a genuine emergency, enforceable noise restrictions are rarely applied — but in a planned setup for renovation or rural use, check your local council’s environmental noise guidelines.
- Parallel capability doubles your output. Some inverter generators (Honda EU, Yamaha EF series) support parallel connection of two identical units — doubling output without buying one large unit. Useful if you already own one smaller unit.
- Second-hand generators need careful inspection. Check oil condition, run hours (if metered), compression (easy pull-start indicates good compression), and test under load before buying. A cheap second-hand generator with a worn carburettor will fail when you need it most.
Local Melbourne Resources
- Bunnings — Generators Range
- Total Tools — Generator Selection
- Kennards Hire — Generator Hire
- WorkSafe Victoria — Fuel Storage Regulations
- Energy Safe Victoria — Electrical Safety Information
Frequently Asked Questions
What size generator do I need to run a standard Melbourne home?
For essentials — fridge, lights, TV, device charging and one 2.5kW split system air conditioner — a 5 kVA generator is typically sufficient for most Melbourne homes. For a larger home with a 7.1kW ducted system or multiple air conditioners, you’ll need 10–15 kVA. Always add up the wattage of everything you want to run simultaneously, including starting surges, before choosing a size.
Can I connect a generator to my home switchboard myself?
No — connecting a generator to your home’s switchboard requires a licensed electrician to install a proper transfer or changeover switch. This is a requirement under Australian electrical safety regulations. Back-feeding the grid without a transfer switch can electrocute energy workers restoring power after an outage. Plug appliances directly into the generator using extension leads for safe, permit-free use.
How much does it cost to run a generator during a Melbourne power outage?
A 5 kVA petrol generator at 50% load uses approximately 2 litres of petrol per hour, costing about $4–$5 per hour at current Melbourne pump prices. A 48-hour outage running essentials would cost roughly $200–$240 in fuel. An inverter generator in the same size range is typically 20–30% more fuel-efficient at partial load, reducing running costs.
Is an inverter generator worth the extra cost for home use?
Yes, for most Melbourne homeowners. Inverter generators are significantly quieter — important in suburban south-eastern Melbourne where neighbours are close — more fuel-efficient at partial load (which is most of the time during an outage), and produce cleaner power that’s safe for laptops, phones and sensitive electronics. The price premium of $300–$600 over a conventional generator is usually worthwhile for regular home backup use.
How long does petrol last in a stored generator?
Standard petrol (including E10) degrades in as little as 30 days if stored in the tank — it forms gum and varnish deposits that clog the carburettor. For long-term storage, drain the fuel tank and carburettor completely, or add a fuel stabiliser (STA-BIL or Briggs & Stratton Fuel Stabiliser) to extend shelf life to 12–24 months. Store petrol in approved AS/NZS 2906 compliant containers in a cool, ventilated area away from ignition sources.
Final Thoughts
Getting the generator size right for your Melbourne home comes down to one thing: making a proper appliance list before you buy. A 5–8 kVA inverter generator covers the essentials for most south-eastern Melbourne households — fridge, some lighting, air conditioning and device charging — during the multi-day outages that follow major storm events. If you want whole-home coverage including electric hot water, plan for 15 kVA or more and budget for a licensed electrician to install a proper transfer switch.