Space heating
Gas heaters provide clean, safe and effective heating through radiant or convection heat, with some heaters providing both. A wide variety of appliance designs and heat outputs are available. Features such as thermostats, programmable timers and temperatures, economy options, remote controls, and child locks are also options.
Choosing the right heater
Consideration should be given to the amount of heat loss due to:
- The structure of the building.
- Insulation within the building.
- Size of windows and the type of glazing.
- Exposure of the building to climatic conditions.
The following calculation is for a building with average exposure and window size and should be considered as a rough guide only.
Room Volume Calculator
| Example: | A room measuring 4m x 4m x 2.4m = 38m3 in room volume Therefore 38m3 x 0.055 = 2.09kW |
The minimum heater size required to heat this room to an ambient temperature in one hour would require output of 2.09kW/hr.
NB: 1kW = 3.6MJ/hr
Please note:
The figure of 0.055 used in the calculation formula is a Watts per m3 coefficient that varies between the different appliances and regions within New Zealand. Be sure to check with the appliance manufacturer for the correct coefficient, room sizing guide and appliance specifications.
Options to consider
Radiant heaters
Radiant heaters offer direct heat and radiate like the sun. Heat travels through the air without raising air temperature directly, but raises the temperature of any surface it touches. Radiated heat is ideal for ‘spot heating’, as a person feels instant warmth when they are directly in the path of the heat. The overall room temperature will eventually rise after all objects in the room have been heated.
These heaters are a good solution for heating areas with a high stud, one greater than the standard 2.4m height, such as
- villas
- churches
- factories
- warehouses
- halls.
Both unflued and flued appliances are available. Refer to the information provided for unflued gas heaters and flued gas heaters within this section.
Convection heaters
Convection heaters heat the air in the room and thus achieve higher overall air temperatures more quickly. A thermostat often controls the output to maintain a desired room temperature. Convection heaters provide even, comfortable heating across the entire room, so are ideal where high overall room air temperatures are required quickly, such as with a kitchen/family room combined design.
Both unflued and flued appliances are available. Refer to the information provided for unflued gas heaters and flued gas heaters within this section.
Flame fires
A gas fire provides instant heat and the look of a realistic open fire, without the danger of the open flame or the need for firewood. A gas fire provides both radiant and convection heating, with the radiant heat warming objects in a room and the convection heat circulating the warmed air.
Both freestanding and in-built gas fires are available. Most freestanding fires must be flued. Some in-built gas fires installed into an existing fireplace may not require flues, but it is strongly recommend by manufacturers that a flexible flue is installed within the chimney breast.
Refer to the information provided for Unflued gas heaters and Flued gas heaters within this section, and Ventilation and flueing.
Unflued gas heaters
Unflued gas heaters operate draw cool air from the room into the heater. The air is warmed by the gas burner and the combusted, heated air is then dispersed from the heater into the room via either radiation, convection or both.
Being unflued, most of these heaters are portable and can be moved from room to room and stored when not in use. Portable gas heaters use flexible 1.5m long connections which plug into bayonet points which can be placed at various locations for convenience and flexibility.
Please note:
While most unflued gas heaters are portable, please note some heaters must be permanently installed on a wall.
Installation
Unflued gas heaters cannot be installed in bedrooms or bathrooms, and bayonet points cannot be installed in these areas or within 1.5m of a doorway of a bedroom or bathroom.
Minimum room size requirements limit the permissible size of an unflued heater for a given space, and are not to be installed in rooms less than this volume. Check the appliance specifications for the minimum room size requirements of any unflued gas heater selected. Manufacturers also provide guidelines on the capacity of the heater and the size room it can heat.
Some portable heaters also require a power source.
For more detailed information on ventilation refer to Ventilation and flueing.
Flued gas heaters
Flued heaters operate by drawing the cool air required for combustion from the room over a heat exchanger. The warmed air is dispersed via radiation or convection into the room. The burnt gases are discharged to the atmosphere via the flue terminal.
Flued gas heaters are available as in-built or free-standing. A range of heat outputs and features are available. Some flued gas heaters are very powerful and capable of heating large areas quickly.
Installation
Flued heaters are permanently installed appliances. Positioning of the appliances within the rooms must take into account how they will be flued to the outside. The flue can be inside an existing fireplace or directly through an outside wall (horizontal flue) or roof (vertical flue).
Most flued heaters also require a power source.
For more detailed information on flueing refer to Ventilation and flueing.