Understanding Electrical Heaters: Cost, Efficiency, and Effectiveness
Published 17 June 2022
Understanding electrical heaters: cost, efficiency, and effectiveness
Understanding the cost and efficiency of different heaters can feel like trying to speak another language. Let’s be real - most people aren’t electricians. On top of that, all houses are different and require different things.
We’ve complied some information here for you to get a bit more of an understanding of how cost, efficiency and effectiveness relate to one another - and what the pros/cons are of different electric plug-in heaters.
What are we talking about here?
We’re just talking about electric plug-in heaters here. These are the heaters that you can plug into a regular power plug, and that run on electricity. These could be your fan heaters, oil column heaters, panel heaters, micathermic and radiant heaters. This category does not include other heaters like heat pumps, gas heaters, or propane heaters.
Cost
When we talk about the cost of running electric plug-in heaters, we’re really talking about the cost of electricity (which is measured in kilowatts), and how much electricity the heater uses. Electricity cost varies depending on where you are, but in Wellington the average cost per kilowatt (kw) of electricity is currently around 29c. A standard rental property heater output is 2.4kw an hour, which will cost 29c x 2.4 = 70c to operate/run for one hour. If a heater like this was put in an average height room (2.4m), it would be able to heat roughly 40m cubed or 16.5m squared of space.
Efficiency
‘Efficient’ is a confusing term when we’re talking about heaters. This is because technically all plug-in electrical heaters are 100% efficient- meaning that for every 1kw of electricity they use, they output 1kw of heat. This is different to other types of heaters- for example heat pumps which are 400% efficient and output 4kw of heat for every 1kw of electricity. We really need to talk about the effectiveness of different heater types to be able to determine what’s best for you, and how much it will cost to heat your space.
Effectiveness
Though all plug-in electrical heaters are 100% ‘efficient’, they’re not all made equal. The type of heat that different electrical heaters output varies a lot. This impacts the time that it takes to heat up a space, the way that the heat feels, how it spreads/travels, and how long-lasting it is.
There are two types of heat that are given off from plug-in electrical heaters- convection and radiant. We have a whole blog post about the differences between these, but we’ll summarise them here too:
Convection heaters heat the air by pulling cold air through the bottom, heating it, and pushing it out the top. This means that convection heaters are quick at providing heat, but if you live in a large open-plan or tall space then you’ll need to keep it on for a long time to heat up all the air in the room. It also means that heat will quickly disperse or blow away, which makes it less suitable for draughty or outdoor settings. Examples: fan heaters, oil column heaters, convection heaters.
Radiant heaters heat surfaces through rays instead of the air. The person or object in front of a radiant heater is heated- like when you stand in the sun. This means that a space will take a bit longer to be heated by a radiant heater, but you’ll really feel toasty. The surfaces that are heated by radiant heat will also slowly release their heat as they cool down, meaning that the heat is much longer lasting. Though these heaters take longer to heat up, the heat won’t blow away/escape and will be longer-lasting, so it may be more cost-effective for your space. Examples: radiant heaters, fire, the sun.
What does this mean for me?
You can see here that while a convection and radiant heater are both 100% efficient, both will be more effective at heating different spaces and for different amounts of time. When you understand this, you can make the right decision for your space.
If you’re picking between plug-in electrical heaters, we usually recommend a heater that’s outputs a mixture of convection and radiant heat. Convection heat will provide the instant heat, while radiant heat will provide the toasty, long-lasting heat. Some examples of these are our Atlantic Solius heater, Glen Dimplex Micathermic heater, or Kent Micathermic panel heater.
If a heater that mixes both is not accessible to you, you’ll need to consider your space to decide between a convection heater and a radiant heater. Finding the one that works better for your space will save you money (as one will probably be more cost efficient for your specific space/needs.)
One thing to note is that recycling centres see a lot of cheap convection heaters (oil/fan) being disposed of at the end of each winter as they’ve broken after a short period. The convection/radiant combination heaters do come at a higher price point but that’s because they really do the best job for most spaces.
Need advice?
Get in touch with our experts to get tailored advice on what’s best for you by booking a free Home Energy Assessment: https://sustaintrust.org.nz/home-energy-assessments or popping into our EcoCentre (Monday to Saturday, 9am - 4.30pm)