What's the best kind of plug in electric heater?

There are lots of different kinds of electrical heaters on the market, and it can be hard to work out which one is the best to use. This page provides information on how to choose the right kind of plug-in electrical heater.


Heat pumps are a very popular choice in New Zealand, because they cost about a third of the cost of a plug in heater to run. But they are expensive to purchase and may not be a realistic option for many people for a range of reasons. Before you dismiss the idea of a heat pump contact the Energy Advice Service about various types of financial assistance available that may help you purchase a heat pump.


Do different plug-in electrical heaters cost different amounts to run?


Plug in heaters are 100% efficient. This means for every dollar spent on electricity, a dollar's worth of heat is produced, regardless of what sort of heater it is.


Sometimes people think that different types of electrical heaters cost different amounts to run. But all types of the plug-in electric heaters convert electricity to heat at the same efficiency (100%).  This means they cost the same to run, regardless of what sort of heater they are. The two things which determine running cost of a plug in heater are:


a) what heat setting or temperature you have the heater on

b) how long you run the heater.


Here are a few examples (based on electricity costs of 24c/kWh) [1]:


1. If you run a heater at 1.2kW (or a half setting) in the morning and in the evening (say 8 hours per day) it will cost: $2.30 per day or $64.50 per month (28 days).

2. If you run the same heater for 8 hours per day but on its full heat setting (2.4kW) it will cost twice as much to run: $4.60 per day or $128.80 per month! (28 days)


What are the different kinds of plug-in heaters?


There are many different kinds of heaters.  They all have their strengths and weaknesses.  Here is a summary of the main types:


Radiant heater - sometimes known as bar heaters, they provide most of their heat by directly heating the object in front of them.  They are generally available in different sizes up to about 2.4 kilowatts (kW).


Fan heater - generally available as small, portable heaters up to 2.4kW, they heat by pushing warm air around the room.  They provide instant heat when turned on.  Fan noise can be disturbing.


Panel/convector heater - sometimes also known as convector heaters these heat the air around them and rely on natural air currents to move heat around the room.  They can be wall mounted or free standing. These can have a slow heat-up and often don't heat rooms evenly, so are generally best for background heating.


Oil column heaters - these heat in a similar way to panel heaters. They are generally available with wheels so can be moved around the room, or from room to room.


Combi-heaters - these combine two forms of heating into a single unit.  Popular combinations include fan-radiant, and fan-convector.  Combining a fan with these other types of heating can improve the heat-up ability and heat distribution around the room.


What is the best kind of heater for different situations?


Because the different kinds of heaters heat in different ways some are better suited to some situations than others.  Here are a few typical heating situations you might find, and suggestions for the most appropriate heater to use.


1. Get up in the morning - need a heater to provide quick heat in the kitchen/dining area for breakfast and getting kids off to school. If the house hasn't been heated through the night you want something that will heat the air quickly - best choice, fan heater or a combi radiant/fan.


2. At home through the day - need background heat in main living area. Best choice probably convector heater (panel or oil column) with thermostat. Alternative is radiant heater with thermostat.


3. Not at home during the day - coming back to a cold house and wanting living room to heat up quickly. A good choice will be a combi radiant/convector heater with thermostat - it provides good heat-up ability combined with the ability to heat just on radiant on lower heat settings, thus avoiding fan noise.


4. Teenager bedroom - convector heaters with thermostats are generally a good, safe option but if there is also the need for quick warm-up of a cold bedroom a combi convector/radiant heater might be ideal.


5. Night - elderly person or infants bedroom - the need is for a lower level of heating (min of 16C for those vulnerable to respiratory conditions). A good choice is likely to be an oil column heater with thermostat.


Other points to consider when choosing a plug-in electrical heater

Good controls: choose a heater that allows a range of heat settings. This is helpful in situations where you require low levels of heat only. Timers are handy because you can set them to turn on before you get up in the morning.


A heater which has these extra features might cost a bit more than basic heaters. However they provide you with greater ability to control how much heat they generate, hence how much money you spend on heating.

Safety: Ensure portable heaters do not tip over easily, and have a cut out switch.  There are fire and electrical shock risks with all electric heaters but especially:

  • radiant heaters - make sure clothes or other flammable materials are not too close to the heater
  • convector heaters - make sure convector heaters are not covered
  • all portable heaters - make sure they are not used near water

Health: Fans may spark off asthma by stirring up dust.

Noise: Check heaters with a fan for noise.

Ease of operation
: Check that the heater controls are accessible and it is clear how to use them.

Portable or fixed? Do you need a heater that can be moved from room to room?

Use a thermostat:  A thermostat avoids overheating the room and creating unnecessary power costs.  


How to find out about good quality brands of heaters


Heaters do vary in their quality. Some heat rooms more effectively and quickly, or have better timers or thermostats than others. "Consumer" magazine provides good information about the quality of different brands of heaters currently on the market. You can also check Consumer NZ website at http://www.consumer.org.nz/ for any information they make available for free.


Get the best out of your electric heater


Insulation and draught stopping

Your heater will be most effective if the house or room you are heating is well insulated:

  • Use lined or thermal curtains.
  • Have the ceiling and floor insulation in your house checked to make sure it is up to Building Code Standards. Ceiling insulation can settle and be less effective after 15-20 years and it may need to be topped up with another layer of insulation. A range of different agencies may be able to provide financial assistance for you to do this - contact the HEAC for more information.
  • Install plastic window insulation kits during the cooler months of the year (available from Community Energy Action at http://www.cea.co.nz/
  • Use draught stopping on internal and external doors, and around window frames.

Use a thermostat

A thermostat avoids overheating the room and creating unnecessary power costs.  Many heaters come with a thermostat built in - these are not ideal because they tend to measure the temperature of the heater rather than the room temperature (especially when heater is on a high heat setting). However they are better than nothing. 


Heating large spaces

The largest plug-in electrical heater you can buy is approximately 2.4 kilowatts. The maximum size room a heater this size can effectively heat is approximately 40-50 cubic meters, or 4mx4mx 2.4m.


If you are heating a large room it will be very expensive to heat using plug-in electrical heaters. This is where other types of heating will be particularly beneficial such as a heat pump, pellet fire (or a clean burning log burner) which will be more affordable to run.  Talk to the Energy Advice Service about the financial assistance that may be available to purchase these kinds of heaters.

Heating spaces with a high ceiling

Rooms with very high ceilings can be hard to keep warm because the warm air will rise and may be lost above your head.  Several actions may be needed to address this:


  • Insulation - make sure the ceiling has good insulation (R3.3 or better) to prevent heat loss.
  • Air circulation - installing a ceiling fan to circulate heat downwards back into the room may be beneficial.
  • Choice of heating - if a ceiling fan is not fitted the best kind of heater is likely to be a radiant heater (providing directional heat at floor level that will shine directly on a person) or a fan heater (which will provide some air circulation).



[1] The actual cost you pay will depend on the tariff plan, 24c/kWh is a typical price in Christchurch in October 2011(including GST and the prompt payment discount). Some electricity plans will be a little lower than this (e.g. all day economy tariffs) and some will be a little higher (low user, all day economy tariff).


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