You are here: Publications > Energy > Warm Homes Technical Report: Detailed Study of Heating Options in New Zealand: Phase 1 Report > Online version >

4 Results of the Literature Review continued

Heating Option 7: Flued gas heater - flame effect (enclosed)
Nature of fuel/energy source	Gas - bottled or reticulated.
Availability of fuel/energy source	Reportedly plentiful despite concerns over commercial gas supplies from New Zealand fields. Recent price increases have been attributed to constraints on availability. There is a limited number of gas suppliers in any location. Reticulated natural gas is only available in the North Island; reticulated LPG is currently only available to a very limited extent in some parts of the South Island, mainly in new subdivisions. Delivery of gas cylinders to some locations may be difficult/expensive.
Fuel/energy consumption	9-13 kg/100 kWh delivered.
Efficiency of conversion of energy to heat	60-85%
Typical operating costs	Ministry for the Environment: 7 cents/kWh Christchurch City Council: 18-21 cents/kWh Own calculations: Bottled gas: 14-21 cents/kWh delivered and 25 cents/day for cylinder hire. Reticulated natural gas: ranges from 7 cents/kWh with 92 cents/day connection charge, to 10.5 cents/kWh with 56 cents/day connection charge, depending on tariff.
Typical capital costs	$2,500-$3,500
Heating capacity	5.5 kW-10 kW
Nature of the heat (radiant, convection, etc)	Convection and radiant.
Fuel/energy handling issues	Gas bottle storage and supply; none apparent for reticulated gas.
Convenience of use	Very easy to use.
Ease of heat control	Good
Effectiveness of heat transfer	Good
Heat-up rate	Fast if fan assisted.
Ability to heat whole house vs single room	An appropriately sized heater can heat a whole house if it is possible to circulate air from the heater throughout the house. However, a heater capable of heating the whole house would have the potential for overheating room where it is located.
Particulate emissions	PM₁₀: 0.03–0.05 g/kg; 0.7-1.1 mg/MJ
Greenhouse gas emissions	NO_x: 1.5 g/kg; 32.5 mg/MJ CO₂: 2500 g/kg; 54,200 mg/MJ
Other emissions	CO: 0.2 g/kg; 4.3 mg/MJ PM_2.5: 0.3 g/kg; 6.5 mg/MJ
Health and safety issues in the home (eg, indoor emissions and moisture)	Risk of gas leaks but no figures are available for incidence of this. However, there is only a low incidence of any notifiable gas accidents (see Risks below), so the risk of gas leaks will also be low.
Embodied energy	Steel; ceramics. Transport of bottled gas.
Special features	–
Risks associated with this option	Long term availability of gas supply. Although there is a risk of explosion in the case of fuel leaks, there are no reports of any instances of this. Data from the Energy Safety Service show a relatively low incidence (15–18 per year) of notifiable accidents for all natural gas and LPG applications. This includes home heating as well as other gas applications.
General comments	Some of these models are designed to partially fit into an open fireplace cavity and therefore reduce the impact on space in the living room.
Suitability for use with heat-transfer system	Possibly, for larger-output models.

Heating Option 8: Flued gas heater - radiant
Nature of fuel/energy source	Gas - bottled or reticulated.
Availability of fuel/energy source	Reportedly plentiful despite concerns over commercial gas supplies from New Zealand fields. Recent price increases have been attributed to constraints on availability. There is a limited number of gas suppliers in any location. Reticulated natural gas is only available in the North Island; reticulated LPG is currently only available to a very limited extent in some parts of the South Island, mainly in new subdivisions. Delivery of gas cylinders to some locations may be difficult/expensive.
Fuel/energy consumption	9-12.5 kg/100 kWh delivered.
Efficiency of conversion of energy to heat	60-80%
Typical operating costs	Ministry for the Environment: 7 cents/kWh Christchurch City Council: 18-21 cents/kWh Own calculations: Bottled gas: 15-20 cents/kWh delivered and 25 cents/day for cylinder hire. Reticulated natural gas: ranges from 11 cents/kWh with 92 cents/day connection charge, to 14 cents/kWh with 56 cents/day connection charge depending on tariff.
Typical capital costs	$800-$1,800
Heating capacity	3 kW-5 kW
Nature of the heat (radiant, convection, etc)	Mainly radiant, with some convection.
Fuel/energy handling issues	Gas bottle storage and supply; none apparent for reticulated gas.
Convenience of use	Very easy to use.
Ease of heat control	Good
Effectiveness of heat transfer	Good
Heat-up rate	Fast
Ability to heat whole house vs single room	The form of heat output, mainly radiant rather than convection, combined with the limited heat output and the lack of means to circulate or distribute this heat make this form of heating unsuitable for heating a whole house. A heater capable of heating the whole house would have the potential for overheating in the room where it is located.
Particulate emissions	PM₁₀: 0.03–0.05 g/kg; 0.8-1.4 mg/MJ
Greenhouse gas emissions	NO_x: 1.5 g/kg; 32.5 mg/MJ CO₂: 2500 g/kg; 54,200 mg/MJ
Other emissions	CO: 0.2 g/kg; 4.3 mg/MJ PM_2.5: 0.3 g/kg; 6.5 mg/MJ
Health and safety issues in the home (eg, indoor emissions and moisture)	Risk of gas leaks, but no figures are available for the incidence of this. However, there is only a low incidence of any notifiable gas accidents (see Risks, below), so the risk of gas leaks will also be low.
Embodied energy	Steel; ceramics. Transport of bottled gas.
Special features	–
Risks associated with this option	Long term availability of gas supply. Although there is a risk of explosion in the case of fuel leaks, there are no reports of any instances of this. Data from the Energy Safety Service show a relatively low incidence (15–18 per year) of notifiable accidents for all natural gas and LPG applications. This includes home heating as well as other gas applications.
General comments	Some of these models are designed to partially fit into an open fireplace cavity and therefore reduce the impact on space in the living room.
Suitability for use with heat-transfer system	No

Heating Option 9: Unflued gas heater - portable
Nature of fuel/energy source	Gas - 9 kg bottles.
Availability of fuel/energy source	Reportedly plentiful despite concerns over commercial gas supplies from New Zealand fields. Recent price increases have been attributed to constraints on availability. 9 kg bottles are widely available from garage forecourts and bottled gas suppliers.
Fuel/energy consumption	9-10 kg/100 kWh delivered.
Efficiency of conversion of energy to heat	80-90%
Typical operating costs	Ministry for the Environment: 12-15 cents/kWh Christchurch City Council: 18-21 cents/kWh Own calculations: 20-22 cents/kWh
Typical capital costs	$250–$350
Heating capacity	3 kW-4 kW
Nature of the heat (radiant, convection, etc)	Mainly radiant, but some convection.
Fuel/energy handling issues	Bottle installation; leaks between bottle and heater.
Convenience of use	Easy to use. No automation options.
Ease of heat control	Reasonable/good control.
Effectiveness of heat transfer	Good
Heat-up rate	Fast
Ability to heat whole house vs single room	Limited - typically small appliances. Appliance can be moved to heat a number of rooms in turn but must not be used in bedrooms.
Particulate emissions	PM₁₀: 0.03g/kg; 0.7 mg/MJ
Greenhouse gas emissions	NO_x: 1.5 g/kg; 42 mg/MJ CO₂: 2500 g/kg; 54230 mg/MJ
Other emissions	CO: 0.2 g/kg; 4.3 mg/MJ PM_2.5: 0.3 g/kg; 6.5 mg/MJ
Health and safety issues in the home (eg, indoor emissions and moisture)	CO with high risk of suffocation from oxygen depletion if used in poorly ventilated areas. Creating ventilation typically results in heat loss. Potential adverse effects from breathing combustion products vented into room. Produce significant amounts of moisture - potentially 1 litre per hour of operation. Radiant heat may ignite materials close to heater. Not permitted for use in bedrooms. Risk of leaks when connecting gas bottle.
Embodied energy	Steel; ceramic. Transport of gas bottles; use of dehumidifier.
Special features	Portable
Risks associated with this option	Health - CO poisoning; dampness. Need regular maintenance to ensure safe operation. Although there is a risk of explosion in the case of fuel leaks, there are no reports of any instances of this. Data from the Energy Safety Service show a relatively low incidence (15–18 per year) of notifiable accidents for all natural gas and LPG applications. This includes home heating as well as other gas applications. Long term availability of gas supply.
General comments	Cheap, accessible, easily introduced form of heating. However, the issues associated with moisture production and emissions of CO make this form of heating an undesirable and potentially unhealthy option. As a result of these negative health effects, these heaters are banned from use in some situations in Australia.
Suitability for use with heat-transfer system	No

Heating Option 10: Gas-fired central heating
Nature of fuel/energy source	Gas - reticulated or 45 kg bottles.
Availability of fuel/energy source	Reportedly plentiful despite concerns over commercial gas supplies from New Zealand fields. Recent price increases have been attributed to constraints on availability. There is a limited number of gas suppliers in any location. Reticulated natural gas is only available in the North Island; reticulated LPG is currently only available to a very limited extent in some parts of the South Island, mainly in new subdivisions. Delivery of gas cylinders to some locations may be difficult/expensive.
Fuel/energy consumption	10-11.5 kg/100 kWh delivered.
Efficiency of conversion of energy to heat	90%
Typical operating costs	Ministry for the Environment: 12-14 cents/kWh Christchurch City Council: 17-21 cents/kWh Own calculations: Bottled gas: 14 cents/kWh delivered and 25 cents/day for cylinder hire. Reticulated natural gas: 10 cents/kWh with connection charge of between 56 and 92 cents/day.
Typical capital costs	$7,000–$15,000 depending on size of house and inclusion of water heating.
Heating capacity	18 kW-30 kW
Nature of the heat (radiant, convection, etc)	Convection
Fuel/energy handling issues	Gas bottle storage and supply; none apparent for reticulated gas.
Convenience of use	Easy
Ease of heat control	Normally timer and thermostatically controlled - can have individual thermostats in each room or on each radiator.
Effectiveness of heat transfer	Good - some losses depending on conduction type.
Heat-up rate	Fast
Ability to heat whole house vs single room	Good - central heating systems are designed specifically to heat the whole house.
Particulate emissions	PM_10: 0.03 g/kg; 0.7 mg/MJ
Greenhouse gas emissions	NO_x: 1.5 g/kg; 33.2 mg/MJ CO₂: 2500 g/kg; 55,300 mg/MJ
Other emissions	CO: 0.2 g/kg; 4.4 mg/MJ PM_2.5: 0.3 g/kg; 6.6 mg/MJ
Health and safety issues in the home (eg, indoor emissions and moisture)	None
Embodied energy	Steel; ceramics. Potentially complex installation.
Special features	High efficiency due to combustion efficiency and controllability. Can provide all the heating and hot water in the house with virtually no need for electricity or supplementary fuel. The heat distribution system lasts for decades. Only the boilers and pumps need replacing every 15-20 years. Easy to change fuels by just changing the boiler. Very quiet. No draughts. Very high heat output with even heat distribution. Can go to maximum heat output easily and conveniently Can add significant value to a home.
Risks associated with this option	Supply of gas. Although there is a risk of explosion in the case of fuel leaks, there are no reports of any instances of this. Data from the Energy Safety Service show a relatively low incidence (15–18 per year) of notifiable accidents for all natural gas and LPG applications. This includes home heating as well as other gas applications.
General comments	This is a very high-quality building service, which is standard throughout the world in countries where heating is required in the winter. Although this system has a high initial cost, the long term benefits and high quality of heating have made it a very popular heating system among those who can afford it. A condensing boiler can be an option to further enhance the efficiency of a central heating system. While these are currently rare in New Zealand, they can offer higher efficiency with a resultant lowering in fuel costs. A condensing boiler would add approximately $1,500 to the cost of a central heating system compared with a conventional boiler.
Suitability for use with heat-transfer system	N/A

Heating Option 11: Electric resistance heater - convector panels
Nature of fuel/energy source	Electricity
Availability of fuel/energy source	Usually readily available but may be subject to shortages at times of peak demand.
Fuel/energy consumption	100 kWh/100 kWh delivered.
Efficiency of conversion of energy to heat	100% at point of use but full fuel-cycle efficiency will be lower when generation and transmission losses are considered.
Typical operating costs	Ministry for the Environment: 11–14.5 cents/kWh Christchurch City Council: 6–20 cents/kWh Own calculations: Standard rate: 19.5 cents/kWh (Meridian Energy, Christchurch) There will also be a fixed connection charge (eg, 63.9 cents/day Meridian Energy, Christchurch). These costs are based on Meridian tariffs for Christchurch; the standard rate is based on the Anytime tariff. Note that a cheaper Economy tariff is also available but supply to some appliances can be interrupted under this agreement so it might not be suitable for all heating applications. The tariffs quoted here offer a 10% discount for prompt payment but this has not been applied to the operating costs presented here.
Typical capital costs	$300–$500
Heating capacity	1k W-3 kW
Nature of the heat (radiant, convection, etc)	Convection
Fuel/energy handling issues	None
Convenience of use	Easy
Ease of heat control	Easy - thermostatically controlled.
Effectiveness of heat transfer	Good but local - single room.
Heat-up rate	Medium/fast
Ability to heat whole house vs single room	Poor
Particulate emissions	None at point of use, but electricity generation will produce particulate emissions when electricity supplied from coal- and gas-powered generators.
Greenhouse gas emissions
Other emissions
Health and safety issues in the home (eg, indoor emissions and moisture)	None - low temperature.
Embodied energy	Steel; plastic.
Special features	–
Risks associated with this option	Rising electricity prices and seasonal constraints on electricity supplies. Potential electricity supply constraints at peak demand times of the day.
General comments	–
Suitability for use with heat-transfer system	No

Heating Option 12: Electric resistance heater - radiant
Nature of fuel/energy source	Electricity
Availability of fuel/energy source	Usually readily available but may be subject to shortages at times of peak demand.
Fuel/energy consumption	100 kWh/100 kWh delivered.
Efficiency of conversion of energy to heat	100% at point of use, but full fuel-cycle efficiency will be lower when generation and transmission losses are considered.
Typical operating costs	Ministry for the Environment: 11–14.5 cents/kWh Christchurch City Council: 6–20 cents/kWh Own calculations: Standard rate: 19.5 cents/kWh (Meridian Energy, Christchurch) There will also be a fixed connection charge (eg, 63.9 cents/day Meridian Energy, Christchurch). These costs are based on Meridian tariffs for Christchurch. The standard rate is based on the Anytime tariff. Note that a cheaper Economy tariff is also available but supply to some appliances can be interrupted under this agreement so it might not be suitable for all heating applications. The tariffs used for these calculations offer a 10% discount for prompt payment but this has not been applied to the operating costs presented here.
Typical capital costs	$50–$250
Heating capacity	1 kW-2.4 kW
Nature of the heat (radiant, convection, etc)	Radiant
Fuel/energy handling issues	None
Convenience of use	Easy
Ease of heat control	Limited - generally either on or off, although some models have a basic thermostat incorporated into the design.
Effectiveness of heat transfer	Intense local heat - suitable for small rooms or particular areas.
Heat-up rate	Fast
Ability to heat whole house vs single room	Poor
Particulate emissions	None at point of use, but electricity generation will produce particulate emissions when electricity supplied from coal- and gas-powered generators.
Greenhouse gas emissions
Other emissions
Health and safety issues in the home (eg, indoor emissions and moisture)	Radiant elements can ignite materials or cause burns.
Embodied energy	Steel; plastic.
Special features	–
Risks associated with this option	Rising electricity prices and seasonal constraints on electricity supplies. Potential electricity supply constraints at peak demand times of the day.
General comments	Very limited heating area.
Suitability for use with heat-transfer system	No

Heating Option 13: Night store
Nature of fuel/energy source	Electricity
Availability of fuel/energy source	Usually readily available but may be subject to shortages at times of peak demand.
Fuel/energy consumption	100 kWh/100 kWh delivered.
Efficiency of conversion of energy to heat	100% at point of use, but full fuel-cycle efficiency will be lower when generation and transmission losses are considered.
Typical operating costs	Ministry for the Environment: 6.6–10cents/kWh Christchurch City Council: 6–10cents/kWh Own calculations: Night rate: 8.4 cents/kWh. There will also be a fixed connection charge (eg, 63.9 cents/day Meridian Energy, Christchurch). These costs are based on Meridian tariffs for Christchurch. The tariff used for these calculations offers a 10% discount for prompt payment, but this has not been applied to the operating costs presented here.
Typical capital costs	$900–$1,500
Heating capacity	1.7 kW-6 kW
Nature of the heat (radiant, convection, etc.)	Convection
Fuel/energy handling issues	None
Convenience of use	Easy
Ease of heat control	Usually thermostatically controlled. However, the heat may be delivered when not required. These heaters are designed to store heat by warming firebricks inside the heater during the night. They then release this heat slowly during the following day, regardless of the ambient temperature. As a result, some heating may occur on warm days even if this is not required.
Effectiveness of heat transfer	Good
Heat-up rate	Slow
Ability to heat whole house vs single room	Poor
Particulate emissions	None at point of use but, electricity generation will produce particulate emissions when electricity supplied from coal- and gas-powered generators.
Greenhouse gas emissions
Other emissions
Health and safety issues in the home (eg, indoor emissions and moisture)	None
Embodied energy	Steel; ceramics; plastic.
Special features	–
Risks associated with this option	Rising electricity prices and seasonal constraints on electricity supplies. Vulnerable to any changes to the current regime of night-rate electricity pricing which is currently common throughout New Zealand.
General comments	Night-store heating is a more suitable option for occupants who are typically at home during the day to receive the benefit of the slow release of heat throughout the day.
Suitability for use with heat-transfer system	No

Heating Option 14: Electric underfloor
Nature of fuel/energy source	Electricity
Availability of fuel/energy source	Usually readily available but may be subject to shortages at times of peak demand.
Fuel/energy consumption	130-160 W/m² 110-125 kWh/100 kWh delivered.
Efficiency of conversion of energy to heat	80–90% at point of use but full fuel-cycle efficiency will be lower when generation and transmission losses are considered.
Typical operating costs	Christchurch City Council: 6–20cents/kWh Own calculations: Night rate: 9-10 cents/kWh. There will also be a fixed connection charge (eg, 63.9 cents/day Meridian Energy, Christchurch). This form of heating is generally connected to a night-rate electricity supply to take advantage of that cheaper form of energy, which can effectively be stored in the thermal mass of a floor. These costs are based on Meridian tariffs for Christchurch. The tariff used for these calculations offers a 10% discount for prompt payment, but this has not been applied to the operating costs presented here.
Typical capital costs	$80-$120/m²
Heating capacity	130-160 W/m²
Nature of the heat (radiant, convection, etc)	Conduction, convection.
Fuel/energy handling issues	None
Convenience of use	Easy
Ease of heat control	Usually thermostatically controlled and/or controllable by individual rooms of a house.
Effectiveness of heat transfer	Good
Heat up rate	Fast
Ability to heat whole house vs single room	Could be installed throughout the entire house.
Particulate emissions	None at point of use, but electricity generation will produce particulate emissions when electricity supplied from coal- and gas-powered generators.
Greenhouse gas emissions
Other emissions
Health and safety issues in the home (eg,. indoor emissions and moisture)	None
Embodied energy	Steel; plastic.
Special features	–
Risks associated with this option	Rising electricity prices. Seasonal constraints on electricity supplies. Vulnerable to any changes to the current regime of night-rate electricity pricing which is currently common throughout New Zealand.
General comments	This option needs to be installed at the time of house construction and is not practical to retrofit into existing homes.
Suitability for use with heat-transfer system	No

[ Previous| Next ]