Portable Heaters

8/6/2019 Portable Heaters

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Portable heatersPortable heaters are potentially a very expensive form of heating. However, if selected wisely andused carefully they can provide a useful heating solution for your home.

If you are renting a home which has no fixed

heating, if the existing fixed heating is

inappropriate and very expensive to run, or if you

need to heat a small area then you may need to

consider using portable heaters. It is important that

you choose them wisely and use them carefully in

situations for which they are most appropriate.

One of the most important things to remember when relying on portable heaters is that, although

they can be cheap to buy (compared to permanent

or fixed heaters), they can be very expensive to

run, especially if used for long periods of time. In

fact, they can cost two to three times more than an

energy efficient gas space heater, while only

heating a relatively small area.

If used wisely, portable heaters can be very useful

in supplementing the main heating system in a

home. For example, heating smaller rooms for

short bursts in the morning and evening using anelectric fan heater is quite economical because of

the short time the heater is actually used. A

permanent energy efficient, high capacity heater,

e.g. a gas space heater or reverse cycle air

conditioner, could then be used to heat larger living

areas for longer periods of time.

As with any heating system, you should always

make sure that your home is able to retain the heat

you put into it in the first place. Insulation, draught-

proofing and good window coverings all play a vital

role in your home’s energy efficiency.Types of heatThere are two main types of heat delivered by

portable heaters—radiant and convection. Each

type of heat is suitable for different circumstances.

Radiant heaters emit heat from a hot surface e.g.

the glowing red bars in a radiator. They heat

people and objects within a room, without directly

warming the air. Radiant heaters are most

appropriate for rooms with large open spaces, high

ceilings, or particularly draughty areas, where it is

difficult to retain warm heated air.

Convection heaters heat a room by filling it with

warm air. They are most effective in closed

insulated rooms, sealed against draughts, with

average ceiling heights, where the heated air can

be continually reheated. Radiant convective

heaters combine the effects of both radiant and

convection heating to varying degrees.

Types of portable heaters

Electric

All portable electric heaters use the general

domestic (GD) peak rate tariff (except if your home

is connected to an off peak tariff). The current cost

is approximately 15 cents/kWh*, i.e. for every 1000

watts or 1 kilowatt (1 kW) of electricity a heater

consumes every hour, you pay 15 cents*.

When running on maximum setting, a 1000 watt

radiator will use exactly the same amount of

electricity as a 1000 watt fan heater or oil-filledcolumn heater, as will any other type of electric

heater with the same wattage. The difference

comes in the type of heat each unit delivers, and

additional features, which can help reduce running

costs, such as thermostats or different heat

settings. See ‘Buying a heater’.

Portable electric heating becomes expensive over

long periods of use, but for short periods this is

quite an economical way to heat small areas.

*Check your bill or ask your energy retailer for your Tariff rate.

Strip heaters and bar radiators

› Produce an intense, radiant heat very quickly.

› Especially useful where localised or spot heating

is required for short periods of time, e.g. to warm

an inactive person in a large room, someone

studying at a desk or working in a draughty

workshop.

› Suitable for bathrooms, they do not produce

warm air, which will be lost when an exhaust fan

is switched on.



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› Do not come with thermostats, and can

therefore be very expensive if run for long

periods of time. They should be switched off

when leaving the room.

› Ensure reflectors are kept clean and shiny for

optimum performance.

› Are less likely to dry the air.

Bar radiator

Electric radiant panel heaters

› Flat panels, which can be fixed to walls or

ceilings, or be portable to provide localised

heating.› Lower wattages than most other electric

portable heaters.

› Provide diffuse warmth rather than intense heat,

using smaller amounts of electricity than strip

radiators. Consequently, are especially suitable

for longer term localised heating requirements in

e.g. offices, studies, bedrooms, etc.

Natural convectors

› Similar to fan convectors, without the fan to

assist in circulating the air. Air naturally rises

when heated. Not recommended for rooms with

high ceilings or bathrooms.

› Quieter to run, but can take a long time to heat a

room.

Fan convectors

› Combine an electric element with a fan to

instantly blow warm air around a room.

› Look for larger, upright models, rather than

small, flat ones. These will generally circulate

larger volumes of air and warm a room more

quickly. This ensures the thermostat will cut in

more often, reducing your heating bills and

providing better comfort.

› Thermostats are available on many models.

› Unsuitable for bathrooms, as the warm air

produced will be lost when an exhaust fan is

switched on.

› Tilt adjustment and oscillation features help to

warm a room more quickly and evenly.› Run on the highest fan speed for maximum

efficiency.

Fan convector

Oil filled column heaters

› These heaters have electric elements immersed

in oil, which heat their outer casing. They

produce natural convective heat, as air is

circulated over the surface of the fins, and also

emit some radiant heat.

› Very quiet operation, ideal for bedrooms.

› They are generally slow to heat up a room and

therefore can be inappropriate in places where

instant heat is required.

› Look for units with inbuilt timers or buy a plug-in

timer.

› Choose units with thermostats to help control

heat output.

› Column heaters continue to emit heat for some

time after they are turned off.

› A fan feature on the appliance can help todistribute heat more quickly around a room.



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› More suitable than fan heaters for larger rooms,

rooms with high ceilings, and uninsulated areas.

They should be placed close to people to gain

the benefit of their radiant heat. They are safer

than radiators as their surfaces do not get red

hot.

Oil filled column heater

Combination heaters

Several models provide both radiant and

convective heating, combining a warm surface with

a fan-assisted convector. Characteristics and

suitability are similar to oil-filled column heaters,

although they have a shorter warm-up time.

Liquefied petroleum gas (LPG) heatersPortable LPG heaters are an option only where

natural gas is not available. Although purchase

costs are between $300–1000, their running costs

are similar to portable electric heaters. These costs

will vary depending on geographical location,

charges for rental of the gas storage cylinders and

delivery of the gas to your home. Portable LPG

heaters are limited in size to 25MJ (generally large

enough to heat most living areas).

› LPG is stored in cylinders outside the house.

The heater can then be transported around the

home and connected to various floor outlets in

the rooms requiring heat.

› These heaters can provide both radiant and

convective heat, or convective only, and are

suitable in most areas around the house except

bathrooms, bedrooms, hallways or saunas.

› LPG portable heaters are unflued and produce

large amounts of water vapour and combustiongases. Adequate ventilation is essential during

heater operation. An area of ventilation of 20 cm

for every MJ/hour rating of the heater should be

maintained. For example, a 25MJ heater

requires a ventilation area of 25 x 20 = 500 cm.

This represents quite a substantial hole in the

wall, especially when you’re trying to keep the

heat in!

› LPG heaters need regular maintenance and

servicing.

LPG portable heater

Kerosene heaters

Although not widely available, portable kerosene

heaters can be cheaper to operate than portable

electric heaters, depending on where the kerosene

is purchased. Kerosene bought from a retail shop

can be four times more expensive than if

purchased from a bulk supplier such as a petrol



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station. Kerosene heaters cost between $300 and

$500 to buy.

› Kerosene heaters produce either radiant or

convective heat, or a combination of both.

› They produce large amounts of water vapour

and because they are unflued, release fumes

into the room, which are often irritating and

odorous. For this reason, adequate ventilationmust be provided during their operation (refer to

the ventilation guidelines under LPG heaters).

The more efficient the heater, the more

complete the combustion of the fuel and the less

fumes produced. Convection heaters generally

burn fuel more efficiently than radiant heaters.

› When purchasing kerosene from a supplier,

make sure that it is definitely kerosene.

Buying a heater When buying any portable heater, look for the

following.

› The type of heater appropriate to your

circumstances (radiant, convective or a

combination). Also, ask yourself how long you

will be operating it for. For immediate heat, you

may choose an electric bar radiator, but for long

term use, a thermostatically controlled heater

would usually be cheaper to run.

› A range of heat settings (e.g. high, medium or

low) or, preferably a thermostatic control. This

allows you to control the output of the heater to

an appropriate setting (the lowest comfortabletemperature is recommended to minimise

running costs). Thermostats can cut running

costs by up to 50%. For every 1°C increase in

temperature over 20°C, your running costs will

increase by 10% to 15%.

› Timers, allowing you to set the heater to come

on and off as required. Some heaters have

these already installed, or they can be bought

separately and plugged in at the wall socket.

› Ensure the heater is sized correctly for the area

you want to heat, and the room’s ability to retainthis heat. You should allow approximately 100

watts or 0.5MJ of heat per square metre of floor

space (assuming the room has an insulated

ceiling and a ceiling height less than 2.7

metres). The maximum output of portable

electric heaters is 2400 watts (2.4 kW), therefore

they can usually heat areas up to 24 m2.

› Check the heater’s noise level before buying;

some fan convectors can be particularly noisy,especially on their highest setting.

Remember, if you will be using a portable heater

for a long periods, running costs become a

concern, often more important than the initial cost

of the unit.



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Running Costs

Heater type andtypical size

Approx.cost per hour (¢)

Type of heat

Suitable for Advantages Disadvantages

Strip heater/ bar radiator

• 800W• 1200W• 2400W

111632

radiant direct personalheating e.g. study,

bathroom,bedroom, draughtyareas; highceilings

quick intensedirect heat

difficult to heatentire room; little

control or flexibilityover heat output;no thermostat

Electric radiantpanel heaters• 160W• 320W• 750W

24

10

radiant study, bathroom,bedroom, draughtyareas

cheaper to run dueto lower wattages;god personalheaters

no thermostat;difficult to heatentire room

Fan heaters withthermostat• 1200W

• 2400W

10-16

20-32

convection bedroom, study,small living room

thermostat tocontrol heatoutput; heats air

quickly

dries out air;expensive over long periods or use

Oil-filled columnwith thermostat• 1200W• 2400W

10-1620-32

radiant,slowconvection

bedroom, study,nursery, smallliving room

thermostat tocontrol heatoutput; quiet

slow to heat up;relativelyexpensive to buy

LPG heaters *• 15 MJ• 25 MJ

30 – 4050 – 60

(dependson cost of

fuel)

radiantconvection

small or largeliving areas

instant heat;cheaper toequivalent portableelectric heatersbottle

flueless, requiresgood ventilation toexhaust fumes andwater vapour;extra cost for LPGdelivery

Keroseneheaters• 2900W(equivalent)(i.e. 0.23 lt/hr)

18 – 19(dependson cost of

fuel)

radiantconvection small living areas instant heat good ventilationrequired toexhaust fumes andwater vapour; fuelcan be expensive

* 1 litre of LPG is equivalent to 0.5 kg of LPG and provides approximately 25 MJ or 7 kW of energy.

The information in this document is derived from various sources and is understood to be correct at the time of publication.However, the information may not be error free and may not be appropriate for a particular purpose. The Sustainable EnergyAuthority accepts no liability whatsoever to any person for any injury, loss or damage that may arise in connection with any useor reliance on the information.

June 2004

Portable Heaters

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