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Which Heater Uses the Least Electricity
Which Heater Uses the Least Electricity

1m read

Which Heater Uses the Least Electricity
Which Heater Uses the Least Electricity1

Do you find yourself bundled up in sweaters at home, desperately trying to stay warm? Do you dread the upcoming winter electricity bill because your heater seems to devour power? You're not alone. As the cooler weather sets in, many of us are torn between staying cosy and having enough money to pay the bills.


The big question on everyone's mind is, "Which heater uses the least electricity?"


Let's embark on a journey together to warm up your home and cool down your energy costs.


Considering Energy-Efficient Heaters in South AfricaThe South African climate varies drastically between provinces. Therefore, the right heater for you lucky Durban folk may differ from that of your Capetonian friends. The choice of heater depends on the specific heating needs and climate of the region. And while we all love a flickering fire, that’s not the only choice available to us today. Let’s take a quick look at what heating options are available before we start doing the sums.


Gas Heaters


Like a cheetah, the gas heater pounces with heat almost immediately. Gas heaters are quick to warm a room and can be turned down lower once the room reaches the ideal temperature. However, they require proper ventilation and are unsuitable for smaller, closed spaces due to the risk of carbon monoxide buildup. Additionally, safety is a factor!


Electric Heaters


Electric heaters include bar heaters, fan heaters, convector heaters and ceramic heaters. Bar and fan heaters start working very quickly, although they are best suited for a small space. Ceramic and convector heaters take a little longer to get up to temperature but can heat larger spaces and most often have an adjustable thermostat to help you manage costs.


Wall panel heaters also fall under this umbrella. Their low wattage means they use less energy, but they also take longer to warm a room. Wall panel heaters range from 400W upward, which means they can be left on during the day to maintain a comfortable temperature. They are a safe choice for bedrooms and for sustained use, and may be the answer to the question, "Which is the cheapest way to heat a room?" - albeit a smaller sized room.


Halogen heaters, infrared panel heaters, and ceramic heaters each provide heat differently: Halogen heaters use halogen bulbs to generate instant radiant heat, best for spot heating in well-insulated areas. Infrared panel heaters emit far infrared heat that warms objects and people directly, providing an efficient heating solution for entire rooms. Ceramic heaters utilise ceramic plates that absorb heat and release it into the room slowly and consistently, making them ideal for prolonged use in larger spaces.


Oil Heaters


Oil heaters, also known as oil-filled radiators, work by heating up the oil enclosed within the fins or columns of the radiator. The oil, acting as a heat reservoir, then gradually releases the heat into the surrounding space, providing a steady and consistent source of warmth. This option offers safe and gentle heating for long, unattended use.


Air Conditioners with a Heating Function


Air conditioners are the Swiss Army knives of climate control, providing both cooling and heating. When it comes to heating, they use a heat pump system that is extremely energy-efficient, effectively reversing the cooling process. An adjustable thermostat makes it easy and convenient to keep your space warm and comfortable.


How Much Electricity Does a Heater Use in South Africa?


So now we come to the burning question of heating costs. When choosing the right heating options for your home, you’ll want to consider two main factors: the initial cost of the appliance and its ongoing energy usage.


A small bar heater will cost just a few hundred Rands, whereas a 12 000 BTU inverter air conditioner costs approximately R8,000.00. However, that little bar heater is pretty power-hungry, can only heat up small areas at a time, and can be a safety hazard. On the other hand, an air conditioner offers heating and cooling and can easily manage a large open-plan room.


Therefore, for the sake of clarity, it’s wise to compare the functionality and capacity of each heater for a specific sized room.


We will assume an average electricity cost of R1,80 per kWh for this example. (Check your local municipality details for the energy costs in your area or visit the Eskom site directly.)


We will consider the heating requirements for a 20 sqm room which would likely be an average-sized bedroom or a small living room, depending on your area.


We’re assuming a cost of R35 per kg for gas, whereby 1kg of gas (when used in a heater) offers the equivalent power of around 14 kWh. This equates to a cost of R2,50 per kWh in gas costs.


All of these calculations exclude the cost of the appliance.


The appliances mentioned below will vary in size, wattage, and features (such as a thermostat), so we are working on averages.




Heater Type


Cost /kWh

Actual cost per hour

Heating Capacity

Gas heater




20 sqm

Oil heater




20 sqm

Electric heaters





Convector heater




20 sqm

3 Bar heater




20 sqm #

Infrared heater




20 sqm #

Wall panel heater




15 sqm

Air conditioner (12000 BTU)




20 - 25 sqm


* Equivalent wattage in gas required to heat a 20 sqm room.

# Theoretically, these heaters can warm a 20 sqm room, but as their heat is fairly localised, it’s recommended to operate two smaller units in a room as opposed to a single larger appliance.


Which Type of Heater is the Cheapest to Run?


The short answer to which heater is the cheapest to run is an inverter air conditioner with a heating function. Aside from their dual role in summer and winter, they can maintain a constant temperature in a room without any input from you, and operate with maximum efficiency.


As we’ve seen, the energy consumption of a heater depends on its wattage. For instance, the wall panel heater wattage starts from 400 watts, making them an energy-efficient choice on the surface. However, they heat up slowly, and these lower-wattage appliances may effectively heat small spaces, but not a larger room.


However, modern tech offers some pretty clever innovations, such as those found in inverter air conditioners. This allows for an efficient heating and cooling process from a lower power output - those are ideas we can get behind!


To get the right answer to this question for your individual needs, it’s also important to factor in the size of your room, the insulation, how many opening doors and windows you have, how much sun the room gets, the ceiling height, and how you use the room.


Optimising Your Heater's Performance


At this point you may be wondering, "How can I make my electric heater cheaper?" The answer lies not just in the type of heater you use but also in how you use it. Simple practices, like using a timer, maintaining the heater, and only heating rooms that are in use, can go a long way in reducing energy costs. Of course, keeping doors and windows closed, improving the insulation of your room, and in some cases, decreasing the temperature by just a couple of degrees can make all the difference.


Which Heater Uses the Least Electricity?


So, back to the burning question: "Which heater uses the least electricity?" It isn't a one-size-fits-all answer. The efficiency of a heater depends on the size of the space, how long the heater is on, and the specific heating needs of your household. However, in terms of energy efficiency, inverter air conditioners come out as clear winners.