How Much Electricity Does an Off-Grid Home Need?

At 100UP, we use a simple starting allowance: 5 kWh per day for the house, plus 5 kWh per person. From there, we calculate actual loads and design the system around winter conditions.

Recent Australian Energy Regulator (AER) data shows that Victorian households typically use around 12–14 kWh of electricity per day, depending on their electricity distribution network. But average household consumption is not necessarily a suitable starting point for an off-grid system. Your appliances, the number of people living in the home and how you use electricity all affect the amount of power you’ll need.

How Much Electricity Does the Average Victorian Household Use?

The AER’s 2024–25 Annual Retail Markets Report provides updated electricity consumption figures for households across Victoria. For the Powercor network, which services much of western Victoria including Ballarat, average residential electricity consumption was approximately 4,965 kWh per year, equivalent to 13.6 kWh per day.

Other Victorian electricity networks reported similar figures:

Source: Australian Energy Regulator, Annual Retail Markets Report 2024–25, Figure 2.19. Daily figures calculated from annual consumption.

These figures provide a useful reference, but they include households with different numbers of occupants, heating systems, appliances and electricity needs.

Why Victorian Electricity Averages Can Be Misleading for Off-Grid Homes

Many Victorian homes use gas for heating, hot water and cooking. That reduces the electricity recorded on their bills.

An all-electric home may use considerably more electricity, particularly through winter when heating demand increases.

That’s important for off-grid properties, where electricity may also be supplying hot water, water pumps, cooking and other equipment that a grid-connected household could be running on gas.

How Much Electricity Does a Three-Person Household Use in Victoria?

The AER’s 2020 residential energy consumption benchmarks provide a more specific comparison based on household size and climate zone.

For a three-person household in Victorian climate zone 6, the benchmark is approximately 5,077 kWh annually, or 13.9 kWh per day.

That is a useful comparison for an existing grid-connected home. However, it is a historical benchmark developed for comparing household energy bills, not a recommendation for off-grid solar sizing.

Actual consumption depends on whether the home uses gas, the efficiency of its appliances, the number of occupants and seasonal demand.

How We Estimate Daily Electricity Use for Off-Grid Homes

When estimating the daily energy needs of an off-grid home, we start with a simple rule:

Daily energy allowance = 5 kWh for the house + 5 kWh for each person.

The first 5 kWh provides a baseline allowance for general household needs. We then add 5 kWh for each occupant to account for increasing electricity use as more people live in the home.

These are 100UP’s preliminary planning allowances, not measured Australian household averages or guaranteed maximum consumption figures.

For example, a three-person household starts at 20 kWh per day. That’s higher than the historical Victorian three-person benchmark of 13.9 kWh, allowing more room for differences in appliances and household use. It’s a starting point, not the final system design.

Why Average Electricity Use Isn’t Enough for Off-Grid Sizing

A grid-connected home can draw additional electricity from the network whenever it needs it. An off-grid property must generate and store its own electricity. If consumption is higher than expected, or solar production is lower than expected, there’s no grid to make up the difference.

We therefore look beyond annual averages and check the factors that matter most:

• Heating and hot water: Electric heating, heat pumps and electric hot water systems change daily consumption.
• Cooking and household appliances: Ovens, induction cooktops, dryers and other appliances add to both energy use and peak demand.
• Pumps and machinery: Bore pumps, pressure pumps, workshop equipment and motors may have high running or starting loads.
• Electric vehicles: Charging at home can add a substantial amount to daily consumption.
• Winter conditions: Shorter days, prolonged cloudy weather and higher heating demand affect system performance.

Once we understand the loads, we calculate the solar generation and battery storage needed to support the property through winter.

For regional Victorian installations, we model conditions around a Ballarat July, including low solar production and a target of approximately two days of battery autonomy.

The aim is to design a system that supports normal household use without routinely depending on a generator.

Daily Energy Use vs Peak Power Demand: kWh and kW

Daily electricity consumption is measured in kilowatt-hours (kWh). It tells us how much energy the household needs over a day.

Inverter capacity is measured in kilowatts (kW). It determines how much electrical power the system can supply at once.

A home using 20 kWh per day might have several large appliances running together. An oven, induction cooktop, water pump and heating system can create a much higher instantaneous demand than the household’s average power use.

That’s why inverter selection needs its own calculation.

How Much Inverter Capacity Does an Off-Grid Home Need?

For a standard residential off-grid system, our approach often starts with at least one 10 kW inverters. The final choice depends on the appliances, expected simultaneous demand, motor starting requirements and the inverter’s actual continuous and surge ratings.

Larger homes, workshops, farms and properties with three-phase equipment may need different inverter configurations.

Modern variable-speed drives and soft-start equipment can also reduce motor starting demand, which we account for when selecting equipment.

The important point is that daily energy consumption helps determine how much energy the system must supply, while peak demand determines the inverter capacity needed to deliver it.

Estimate Your Daily Off Grid Energy Needs

If you’re planning an off-grid home in Victoria, the 5 kWh + 5 kWh per person rule gives you a straightforward place to start.

You don’t need to know every appliance specification before making an initial estimate. But before choosing a system, we’ll need to understand what you’re running, how often you use it and whether you expect your electricity needs to increase.

Try our off-grid solar calculator to estimate your daily energy needs, then we can work through the system requirements for your property.

References

1. Australian Energy Regulator. Annual Retail Markets Report 2024–25, Figure 2.19, average annual household electricity usage.
2. Australian Energy Regulator / Frontier Economics. Residential Energy Consumption Benchmarks, December 2020.
3. Australian Energy Market Commission. Electricity Consumption Benchmarks, final rule determination, August 2023.

Published electricity consumption figures describe grid-connected households and do not establish the required capacity of an individual off-grid system. The 100UP starting allowance is an estimating method and is refined using property-specific loads and winter system modelling.