Skip to content   Skip to footer navigation 

How to buy the best gas heater for your needs

Flued or portable? That's the number one question when it comes to gas heaters.

gas heater hand changing temp

What do you look for in a gas heater?

A gas heater is a great solution for heating a large space quickly and cost-effectively. We explain the difference between flued and portable heaters and some tips to look out for.

Looking for the best gas heater?

See our expert product reviews.

How do I choose a gas heater?

Do you need a gas heater?

How much space are you heating? The measurement of a gas heater's warming capacity isn't just about room size, it's also about how quickly the heater can warm the space. 

The room size and local climate will determine what size gas heater will effectively heat your room. 

Portable, or unflued gas heaters must not be installed in a room too small for their rated capacity due to the emissions they produce. For fast heating, choose the biggest capacity (measured in MJ/h) suitable for the room size. A lower capacity heater can still heat the room but will be slower.

What size gas heater should I get?

Once you've decided you need a gas heater you'll need to consider the size. Overspending on a larger gas heater than necessary means wasted money upfront and higher ongoing running costs. Under-spending means you aren't able to heat your room properly.

Use the kWh heat output in our gas heater review to decide roughly what size heater you need. 1 kWh roughly heats 10 square metres. 

There are heaps of caveats and variables to this. 

The climate zone you live in, your ceiling height, whether rooms next to the one you are heating are heated, whether you've got insulation, whether the room gets direct sunlight, how big the windows are and whether they have solid curtains or are double glazed. 

Room size kW output Gas consumption Purchase cost ($) Running cost/2hrs
Small (29 - 42sqm) 2.9 - 4.2kW 13-15MJ/h $599 - $1275 59c - $1.00
Medium (46 - 66sqm) 3.4 - 6.6kW 18-21MJ/h $849 - $1149 $1.08 - $1.33
Large (52 - 82sqm) 5.2 - 8.2kW 23+MJ/h $770 - $2090 $1.44 - $2.06

Which type of gas heater do I need? A flued or portable gas heater?

A flue is a pipe that carries exhaust gases from your heater or fireplace to the outdoors, saving your room from being filled with fumes. They're pretty important. If you're a renter or don't want to go to all the fuss of a flue, you might want to look at a portable, or unflued, gas heater. There are benefits and drawbacks to both flued and portable heaters. 

Pros of a portable gas heater

  • They're portable – so you can point them in different directions, move them from room to room, store them away in summer and take them with you when you move house.
  • They're very efficient – about 90% of the energy content of the gas is transformed into heat. All models sold in Australia have to be certified and carry an efficiency label (up to six stars, with six being the best).
  • They provide instant heat – and lots of it. Unflued gas heaters come with a capacity of up to 25 MJ/h (megajoules per hour). That's equivalent to more than 6kW of electric heating – the same as you'd get from three 2kW electric heaters.
  • They're much cheaper to run than portable electric heaters, even though they're a lot more expensive to buy.
  • They produce a quarter to a third of the carbon of an equivalent electric heater (unless you get your electricity from renewable sources).
  • Modern models have a range of safety features that switch the heater off in case something's wrong – for example, an oxygen depletion sensor if the oxygen level in the room gets too low, flame failure protection in case the flame gets extinguished, and a tilt switch in case the heater tips over.

Cons of a portable gas heater

  • Not having a flue means that emissions from the gas combustion process in the heater are vented back into your room.
  • They're illegal to use in bedrooms, bathrooms and other small or badly ventilated rooms, so for those areas you need a flued heater (which vents the products of combustion via a flue to the outside), or an electric heater.
  • Some states have further restrictions on using this heater type – check with a gas plumber or retailer. Victoria no longer allows gas bayonets to be installed for the purpose of an unflued gas heater.
  • An unflued gas heater produces carbon monoxide (CO) and nitrous oxides (NOx), but only in relatively small quantities – Australian emission standards are among the toughest in the world. However, they can still cause problems for asthmatics or people with certain allergies or respiratory problems – a flued gas heater would be a better solution for these people.
  • Water vapour from the combustion process can condense on walls and ceilings and cause mould, which is why ventilation is so important.

What to look for in flued gas heaters

flued gas heater
  • Remote controls allow you to control the temperature settings and fan speeds, with some models offering both wired and wireless versions so they can extend a further distance.
  • Thermostats make it easier to set a desired temperature.
  • Programmable timers will help with energy saving. Most can be programmed to turn on and off during a 24-hour period.
  • Child locks are available on some models, and are a very important safety concern for us here at CHOICE. We would like to see this feature on more products in future.
  • Electronic ignition is great, because it means potential energy savings due to not having to have a pilot light running at all times.
  • A filter-clean warning feature is very useful, so you can be sure to clean it regularly and as needed.
  • An LPG conversion kit allows you to operate the heater in areas without natural gas, but be careful - operating costs will be higher as a result.

What about installation?

Installation will cost you on top of the heater itself. Buying last year's model and asking for a discount might help, so you can put the savings towards the installation.

CHOICE strongly recommends professional installation for these heaters, as many things can go wrong. When our experts tested a range of flued heaters in 2017, in many cases there were incorrect parts supplied or manuals incorrectly printed – in our 2010 test some heaters were not assembled correctly to the point of being potentially dangerous.

Do I need a chimney for a flued gas heater?

Not necessarily. Most units can be installed into an existing fireplace, with an existing chimney accommodating the flue; otherwise you can use a firebox and put the unit anywhere in the room, as long as you can incorporate a flue.


The average price range for flued heaters is from $1200 to $2200.

What to look for in portable gas heaters

unflued portable gas heater

There are two different types of portable, or unflued gas heaters:

  • Convection heaters rely on the natural movement of hot air, but also have a fan to speed things up. They're often electronically controlled, which means they have, for example, a thermostat and a remote control. A thermostat is particularly useful, as it provides better temperature control than the heat and fan settings on models that aren't electronically controlled. However, electronically controlled models also use standby power — some more than 10W. The external surfaces on convectors shouldn't get very hot.
  • Radiant-convection models also rely on convection, but have an exposed area that radiates heat into the room. Radiant convectors tend to be cheaper to buy, but have fewer features (no thermostat, timer, remote control, etc) than similarly sized convection heaters. They have manually operated electronic ignition (you need to press the ignition button and hold it down for about 20 seconds).


The average price range for portable heaters is from $400 to $1400.

Looking for the best gas heater?

See our expert product reviews.

Leave a comment

Display comments