Do Oil Heaters Use a Lot of Electricity? Complete Guide
Oil-filled heaters can use a noticeable amount of electricity because they rely on electric resistance heating. A 1,500W oil heater consumes up to 1.5kWh for every hour its heating element operates. At an example electricity rate of A$0.35 per kWh, that equals approximately A$0.53 per hour at full power.
Actual oil heater electricity usage is usually lower once the room reaches the selected temperature and the thermostat begins switching the heating element on and off. However, running an oil heater for many hours each day can still add significantly to winter electricity bills.
This guide explains how oil-filled heaters work, how to calculate their running costs, what affects their energy use and how they compare with other heating options in Australia.
How Do Oil-Filled Radiators Work?
Oil-filled radiators are electric heaters that use electricity to heat a special thermal oil sealed inside the metal fins. Although they contain oil, they do not burn oil as fuel. Instead, the oil works as a heat-transfer medium that absorbs and stores heat before gradually releasing it into the room.
When the heating element turns on, it warms the oil inside the radiator. The heated oil then circulates through the fins, allowing the unit to distribute steady warmth through natural convection. Once the set temperature is reached, the thermostat switches the heating element on and off to maintain the room temperature.
This heat retention is one of the main reasons oil-filled heaters can provide consistent warmth even after the element stops running. However, their oil heater power use still depends on the heater’s wattage, how long it operates, and the conditions of the room.
How Much Electricity Does an Oil-Filled Heater Use?
Oil heater power consumption depends primarily on the appliance’s wattage and how long the heating element remains active.
To estimate oil heater power consumption, you can use this simple formula:
Electricity usage in kWh = Heater power in kW × Operating time in hours
The following table shows the maximum running cost of several heater sizes at an example electricity rate of A$0.35 per kWh.
Heater rating | Maximum electricity use per hour | Cost per hour | Cost over 8 hours |
1,000W | 1kWh | A$0.35 | A$2.80 |
1,500W | 1.5kWh | A$0.53 | A$4.20 |
2,400W | 2.4kWh | A$0.84 | A$6.72 |
These figures assume that the heating element remains on continuously. In normal use, the thermostat usually cycles the element on and off after the room reaches the selected temperature, so actual oil heater electricity usage may be lower.
To estimate your own oil radiator running cost, check the heater’s power rating and multiply its expected electricity usage by the applicable price per kWh shown on your electricity bill.
What Affects Oil Heater Power Consumption?
A heater’s wattage indicates its maximum power draw, but it does not tell you exactly how much electricity the appliance will use during an evening or over an entire winter. Several other factors determine how frequently the heating element needs to operate.
1. Heater Wattage
A higher-wattage oil heater can usually warm a larger space or raise the temperature more quickly, but it also draws more electricity while its heating element is operating.
A heater that is too small for the room may run continuously without reaching the desired temperature. An unnecessarily large model may have a higher maximum power draw than the space requires. Choosing a heater that suits the room can improve comfort without creating unnecessary energy demand.
2. Operating Time and Usage Habits
The longer an oil heater runs, the more electricity it will consume. Leaving a heater on for many hours or using higher temperature settings can significantly increase running costs. Using timers and thermostats can help control unnecessary heating.
3. Room Size and Insulation
Room conditions have a major impact on oil radiator electricity consumption. Large rooms, high ceilings, draughty windows, and poor insulation allow heat to escape faster, causing the heater to work harder. Well-insulated rooms retain warmth longer and require less energy.
4. Thermostat Settings
Oil-filled heaters use thermostats to maintain a selected temperature by cycling the heating element on and off. Keeping the temperature at a comfortable level, usually around 18–20°C in winter, can reduce electricity consumption compared with overheating the room.
5. Electricity Tariff
Your local electricity tariff also affects the final running cost. For Australian households, using an oil heater during peak electricity periods may result in higher bills, especially with time-of-use energy plans.
When estimating the total oil radiator running cost, factors such as electricity rates, daily operating hours, thermostat cycles, and room insulation should all be considered rather than focusing only on the heater’s rated wattage.
Oil Heater Power Consumption vs Other Electric Heaters
When comparing oil heater power consumption with other electric heaters, the key difference is not always the amount of electricity used, but how efficiently the heat is delivered and maintained. A 1,500W oil heater and a 1,500W fan heater will consume a similar amount of electricity when running at full power, but their heating performance can be different.
Heater type | Best suited to | Heating speed | Heat after switching off | Energy considerations |
Oil-filled heater | Bedrooms, studies and enclosed rooms | Slow | Continues releasing stored heat | Similar electricity use to other resistance heaters of the same wattage |
Fan heater | Short periods and direct personal heating | Fast | Little retained heat | Can become costly when operated continuously |
Panel or convection heater | Small to medium enclosed rooms | Moderate | Limited retained heat | Consumption depends on wattage and thermostat cycling |
Radiant heater | Heating people or a targeted area | Fast and direct | Little retained heat | Can be practical when only a small occupied area needs warmth |
Reverse-cycle air conditioner | Regular heating or larger spaces | Fast | Maintains room temperature | Usually uses less electricity for the same useful heat output |
For households wondering whether oil heaters are energy efficient, the answer depends on how and where they are used. Oil-filled heaters are particularly suitable for users who need consistent warmth for several hours because their thermal oil stores heat and continues releasing warmth after the heating element cycles off.
However, for heating larger living areas or running a heater for long periods, a reverse-cycle air conditioner may use less electricity because it transfers heat rather than converting electricity directly into heat. When considering the cheapest way to heat a house, households should also compare room size, insulation, local electricity tariffs and the number of hours heating is required each day.
How to Reduce Oil Heater Electricity Consumption
Oil-filled heaters can provide comfortable and consistent warmth, but careful use is important when managing winter energy costs.
Choose the Right Heater Size
Selecting an oil heater that matches your room size is one of the easiest ways to avoid unnecessary energy use. An undersized heater may need to operate continuously because it struggles to reach the desired temperature, while an oversized model may consume more electricity than needed.
For small bedrooms, studies, and home offices, a lower-wattage oil heater is often sufficient. Larger living areas may require a higher-output model, especially in homes with high ceilings or poor insulation.
Use the Thermostat and Timer Together
The thermostat plays an important role in controlling oil heater power usage. A temperature of around 18–20°C is generally suitable for winter, while a timer can limit heating to the periods when the room is occupied. Always follow the manufacturer’s instructions, keep the heater clear of curtains and furniture, and switch it off before going to bed or leaving the house.
Improve Home Insulation and Reduce Heat Loss
A heater can only work efficiently when the heat stays inside the room. Poor insulation, draughty windows, and gaps around doors can cause warmth to escape quickly, forcing the oil heater to run for longer periods.
Simple improvements can make a noticeable difference, including:
Sealing gaps around doors and windows
Using thermal curtains or blinds
Closing doors to unused rooms
Adding rugs to reduce heat loss through floors
A well-insulated room retains heat for longer, allowing the thermostat to cycle the heating element less frequently.
Position the Heater Correctly
The position of your oil heater can affect how efficiently heat spreads throughout the room. Place the heater in an open area where warm air can circulate naturally.
Avoid placing it:
Behind furniture
Close to curtains or other objects that block airflow
Near frequently opened doors or windows
A suitable position helps the heater distribute warmth more evenly and reduces unnecessary operating time.
Check Your Electricity Plan
Households on a time-of-use tariff may pay more for electricity during evening peak periods. Check the actual peak and off-peak times listed by your retailer, as schedules and rates vary between plans and locations.
Do not extend the total heating period simply to access a lower tariff. Preheating a room for several additional hours may increase total electricity consumption even if some of that power is purchased at a cheaper rate.
Turn the Heater Off When It Is Not Needed
Switch the heater off when the room is unoccupied, before leaving the house and before going to sleep. The Australian Government specifically recommends turning heaters off overnight and when away from home.
Can a Portable Power Station Run an Oil Heater?
Yes, a portable power station can run an oil heater, provided its continuous AC output is higher than the heater’s rated wattage. For example, a 1,500W oil-filled heater requires a power station that can continuously supply at least 1,500W, with additional capacity available for any other connected appliances.
However, output power and battery capacity are different considerations. A power station may have enough output to operate the heater but still provide only a limited runtime. A 1,500W heater can consume up to 1.5kWh for every hour its heating element remains active, meaning electric heating can drain a portable battery relatively quickly. Actual runtime will depend on the thermostat cycle, selected heat setting, battery capacity, inverter losses and other connected devices.
A portable power station does not reduce oil heater electricity usage. Instead, it can provide temporary heating during a power outage or allow stored solar energy to be used when grid electricity is unavailable or more expensive.
EcoFlow DELTA 3 Ultra Plus Portable Power Station
The EcoFlow DELTA 3 Ultra Plus has a 3,072Wh base capacity, a 3,600W rated AC output and capacity expansion from approximately 3kWh to 11kWh. Its rated output is sufficient for many standard oil-filled heaters, provided the heater and all other connected loads remain within the system’s output limit.
The unit supports up to 2,300W AC charging and can recharge from 0% to 80% in approximately 75 minutes under specified test conditions. However, a 1,500W oil heater would consume 1.5kWh during each hour of continuous full-power operation, so the base battery is better suited to short-term heating support than prolonged overnight use.
EcoFlow DELTA Pro Ultra Whole-Home Backup Battery
For households requiring greater backup capacity, the EcoFlow DELTA Pro Ultra provides a base capacity of 6,144Wh, expandable to 30kWh, with a 6,900W AC output. The larger capacity can support selected appliances for longer, although resistance heating will still consume stored energy quickly. When paired with a compatible EcoFlow Transfer Switch, the DELTA Pro Ultra can supply selected household circuits from backup power.
For efficient backup planning, prioritise essential loads such as refrigeration, lighting, communication equipment and medical devices before allocating substantial battery capacity to electric heating.
Conclusion
So, do oil heaters use a lot of electricity? They can, particularly when operated at a high setting for several hours. A 1,500W oil heater uses up to 1.5kWh per hour while its heating element is active, which can add noticeably to winter electricity bills.
Oil-filled heaters remain a practical choice for quiet, steady heating in small, enclosed and well-insulated rooms. Choosing the right heater size, setting the thermostat between 18°C and 20°C, reducing draughts and heating only occupied spaces can help control running costs.
For regular heating of larger areas, a reverse-cycle air conditioner will usually provide more heat from each unit of electricity consumed. Portable power stations can support an oil heater temporarily during an outage, but their output, capacity and expected runtime should be assessed before use.
FAQs
What are the disadvantages of an oil heater?
Although oil heaters provide quiet and steady warmth, they also have some limitations. They usually take longer to heat a room compared with fan heaters, making them less suitable for quick bursts of heat. Oil-filled models are also heavier and less portable. In addition, they may not be the most efficient choice for large open spaces where a reverse cycle air conditioner can provide heating more effectively.
Is it cheaper to leave an oil heater on all the time?
Leaving an oil heater on continuously is usually not the most cost-effective option. While the thermostat helps reduce power use by cycling the heating element, running the heater when a room is unoccupied still consumes electricity. Using timers, maintaining a moderate temperature, and heating only occupied spaces can help reduce oil heater running costs while keeping your home comfortable.
Is it safe to leave an oil heater on overnight?
The safest approach is to switch the heater off before going to sleep. Even though oil-filled heaters do not have an exposed glowing element, they are still high-power electrical appliances and can present a fire risk if they are damaged, covered or placed too close to combustible materials.
Always follow the manufacturer’s instructions, plug the heater into a suitable outlet, keep it clear of curtains, bedding and furniture, and avoid leaving it unattended for extended periods.