Can a Portable Power Station Power a House?

A portable power station cannot power a whole New Zealand home as usual, because the average household uses about 19.5 kWh per day and a large unit stores only 2.1 to 2.3 kWh. It can keep essentials such as the fridge, lights, WiFi router and phone charging going through a power cut. This guide shows how to calculate runtimes, explains the NZ rules for connecting to a switchboard, compares battery and generator backup, and offers practical tips to make a charge last longer.

Yes, for the things that matter most in a power cut. No, not for your whole house running as normal. The average New Zealand household used 7,107 kWh of electricity in the 12 months to September 2024, about 19.5 kWh a day. A large portable power station can store 2.1 to 2.3 kWh, roughly 11 to 12 per cent of that.

When the grid goes down, though, most people do not need a full day of normal power. You need food kept cold and fresh, the lights on, WiFi routers running, and devices charged. A large unit has enough energy and output for all of that, with room for short bursts from a kettle or microwave. What you cannot expect is the hot water cylinder, oven or heat pump running for hours on end.

How Much Power Does an NZ Home Actually Use?

Start with the basics. Kilowatt hours (kWh) measure battery capacity, like the size of a fuel tank. Watts (W) measure how fast you draw from it, like how hard your foot is on the accelerator.

At 19.5 kWh a day, the average Kiwi home draws around 810 watts around the clock. Live normally on a 2.3 kWh battery, and it would be flat in under three hours.

EECA says hot water heating makes up about 30% of the average household's energy use. That is roughly 5.8 kWh per day, more than two and a half times what a single power station can hold.

What a Portable Power Station Can Run in a Power Cut

Appliance labels show rated input in watts. Divide the battery capacity in watt-hours by that figure to get an approximate runtime in hours. The table does that sum for the 2,304 Wh GT Power GTi20000G5 and the 2.1 kWh Instagrid One, both sold through our portable power stations range.

These are simple calculations before inverter losses, not test results, so real-world runtimes are lower.

A fridge compressor cycles on and off, so label wattage overstates what it actually uses. For fridges, check the Energy Rating label, which shows kWh per year. A fridge rated at 400 kWh a year uses about 1.1 kWh a day, so a full GT Power unit would cover it for roughly two days before losses.

Keep the total load within the unit's output rating: 3,600 W continuous AC output for the GT Power, and 230 V at 16 A for the Instagrid One.

High surge ratings (up to 20,000 W on the GT Power, 18,000 W peak on the Instagrid One) supply the starting power motors need, but continuous output decides what you can run.

Why It Won't Run Your Whole House

Stored energy: one charge covers only 11 to 12 per cent of an average day, and heating drains it fastest. Output rating: a house can easily pull more than a portable unit's rated output when several big appliances run together, and the unit shuts down to protect itself.

Out of scope for a single power station:

• Hot water cylinder
• Electric oven and cooktop
• Clothes dryer
• EV charging
• Heat pumps for extended periods

Nor is one unit a substitute for a permanent system designed for off-grid living.

Can You Connect One to Your Switchboard?

Not yourself. Connecting any alternative supply to house wiring is prescribed electrical work under the Electricity (Safety) Regulations 2010. WorkSafe states it must be done by a licensed electrical worker, with the mains phase and neutral isolated so electricity cannot feed back into the lines.

Safety first: Backfeeding can electrocute line workers repairing the network outside your home. Never use a cable with a plug on both ends to feed power into a wall socket.

Until the manufacturers confirm these units suit a changeover inlet, plug appliances directly into the unit using quality extension leads rated for the load. If your bore pump is hardwired, talk to a licensed electrician before an outage, not during one.

Portable Power Station vs Generator for Home Backup

For short outages, a power station hits the sweet spot. For lifestyle blocks and rural homes that can lose power for days or even a week, a generator makes more sense: a flat battery needs mains power to recharge, while a generator runs as long as you have fuel.

For this job, compare the GT Power inverter generator range, including the GT4000ESI Solar Backup Package. To switch the house over safely, a licensed electrician can install a transfer switch, such as the GT Power Dual Function ATS, designed for use with a generator.

Petrol generators must run outdoors, at a safe distance from the house, because of carbon monoxide. For other alternatives, browse the full generators range.

How to Make Your Charge Last Longer in an Outage

• Prioritise essentials: fridge, freezer, water pump, lights and communications.
• Keep fridge and freezer doors shut so the compressor works less.
• Avoid heating loads such as kettles, toasters and heaters.
• Run big items one at a time to stay under the continuous limit.
• Charge up ahead of storm warnings so you start every outage with a full battery.
• Choose a dry, stable location for the unit, out of the rain.
• Recharge as soon as the mains returns. Fast AC charging takes about 2.2 hours on the GT Power, and the Instagrid One recharges in about 2 hours.

Cyclone Gabrielle in 2023 showed how long outages can last when wind and flooding take lines down. If outages in your region tend to run for days, plan for a generator as well.

One Unit for the Jobsite and the Home

The same portable power source that runs a tradie's power tools at work from Monday to Friday can keep the fridge cold and lights on at home during an outage.

The GT Power GTi20000G5 5th Generation portable power station stores 2,304 Wh of NCA lithium energy and delivers 3,600 W of continuous power, with up to 20,000 W of surge. It has two 230 V AC output ports, runs below 30 dB, is free of exhaust fumes and weighs 24 kg.

The Instagrid One portable battery power unit holds 2.1 kWh and delivers 230 V, 16 A output with 18,000 W peak power. It is compact at 20 kg, light enough for a one-hand lift, and designed for off-grid use. For expansion, you can link up to three units for 6.3 kWh. It is made in Germany and carries a four-year warranty.

Neither will run your whole house, but either will keep your food cold, your lights on, and your household connected during a typical outage. Whether you live in Auckland or on a rural block, the first step when choosing a power station in NZ is to match the unit to your essential loads and budget.