Electric heating

Most types of electric heaters have roughly the same efficiency, around 90-95%. In other words, they give just under a dollars worth of heat for each dollar of electricity they use.

Unless it is about a heat pump, don't believe any advertising that claims one type of electric heater is lots more efficient than others.

Different kinds of electric heaters – such as radiant, fan, convection and night store heaters – suit different circumstances.

Running costs

To work out how much a heater costs to run for an hour in cents, take the capacity of the heater in kilowatts (1 kW = 1,000 Watts) and multiply by 23. The average residential cost of a unit of electricity is 23 cents.^[1]

Types of heaters

Radiant heaters

The familiar bar heater is a radiant heater. These mainly heat objects and people rather than the air in a room, so can be useful in large rooms where you only need the heat in one area. These heaters can be a fire risk and are dangerous to children.

There are more modern versions of the radiant heater, often called a panel , marble or stonestore heater, where the elements are behind, or inside a panel or other mass made of metal, brick, stone or something more expesive like marble.

These heaters give a more even, lower temperature heat, but still cost the same to run for a set amount of heat. They are not any more efficient than any other type of electric heater, don't believe any marketing that says they are.

Fan heaters

Fan heaters, also known as ceramic heaters, can be noisy and are slightly less efficient as some of the energy they use runs the fan. They distribute heated air around the room rather than letting it form a layer of hot air at ceiling height. They are good for quick warmth in smaller rooms, for instance in the kitchen or bathroom in the morning, which require heating for short periods of time.

Convection heaters

A convection heater warms the air rather than surfaces. THese include column heaters (oil and 'oil-free') and fan convection heaters.

These are a good choice for medium-sized rooms that require heating for longer periods of time, such as living rooms. They steadily warm the air by convection – the hot air rising – and provide background warmth. Their surface temperatures are relatively low, which makes them safer than hot radiant heaters. Note that they can be tipped over by children unless specially designed or fixed in place.

Night store heaters

Night store heaters store heat from cheaper off-peak electricity at night and release it during the day. They can be economical for houses that are occupied during the day, and where there is a cheaper night rate for electricity.

Their efficiency varies between 50% and 95 % as they sometimes waste energy by producing heat when it is not needed.

If your house is empty during the day, these are not a good heating option for you.

Underfloor heating

Electric underfloor heating is similar to an electric blanket that goes on top of your floor. It goes between any floor covering like carpet or thin timber flooring and the floor itself.

Any covering that goes on top of the electric underfloor heating makes it harder for the heat to get into the room. This can be counteracted with much better insulation underneath the floor to minimise the heat lost downwards.

Underfloor heating on a concrete slab floor that isn’t fully insulated from the ground below and around it, will result in you spending money to heat a lot of soil and rock underneath your house.

Although underfloor heating can heat large areas well, it can be expensive to run simply due to the size of the heater.

Notes:

^[1] Ministry of Economic Development, 2008, Schedule of Domestic Electricity Prices: Updated to 15 November 2008, 2008, (online).