A telephone survey of domestic heating methods and fuels for Auckland was carried out by Digipoll in December 2004. This involved surveying 151 households within the Auckland Region as defined by the 2001 census.
Survey details are shown in Table 27.1. The number of households for 2004 was estimated based on 2001 census data for occupied dwellings, extrapolated for 2004 based on Statistics New Zealand population projections. [New Zealand Statistics 2004, www.stats.govt.nz] The latter suggest a population increase for Auckland of 37% by 2021. [High, medium and low population projections were estimated by Statistics New Zealand. The value used is the medium population projection.]
27.1 Home heating methods and fuels
The Digipoll survey was used to collect information on home heating methods and fuels for Auckland. These data were collected for the purpose of evaluating the impact of variations in heating methods on air quality in Auckland, in particular the extent of change required to achieve the national environmental standard for PM10. This section presents the results of the home heating survey for Auckland largely in tabular form, in the expectation that these results will be of value in other assessments (eg, emission inventory studies).
Tables 27.2 and 27.3 show domestic heating methods and fuels used for main living areas in Auckland houses, and seasonal variations in heating behaviour. The commonest methods of heating the main living area in Auckland were electricity (48%) and gas (35%). Many households used more than one method of heating in their main living area.
Around 9% of households using open fires for home heating carried out heating during the summer months (Table 27.3). The quantities of fuel used per day during non-winter months were typically less than during the winter (Table 27.4). The main exception in this case was multi-fuel burners using wood. These results do not suggest that individual households heating with multi-fuel burners use more fuel during the non-winter months. The higher average is more likely to reflect differences in the sample population, with fewer households burning during the non-winter months. Data are not presented for all heating methods, because there was a high non-response rate for questions relating to seasonal variations for some heating types.
27.2 Insulation, cost of heating, income, and house age and size
In addition to collecting data for the purpose of evaluating the impact of variations in heating methods on air quality, information was collected on a number of variables relevant to the Ministry for the Environment's Warm Homes Project. Relevant data for Auckland are presented in this section.
Figure 27.1 shows that the proportion of households using gas systems that are properly flued in Auckland is around 35%. This compares to a national average of 24%.
The amount spent on heating for a winter month, by heating method, is shown in Table 27.5. In Auckland, households heating using open fires and gas spent less per month on average ($30 and $43, respectively) than those using other heating methods.
Figure 27.2 shows the average heating costs, home ownership, age of dwelling and number of bedrooms for households in Auckland. Around 26% of the respondents in Auckland were living in rental accommodation. This compares with a national average of around 20%.
One factor influencing the amount spent on different heating methods is the ability of households using solid fuel burners to obtain wood free of charge. Figure 27.3 shows that around 60% of the wood used on open fires and wood burners in Auckland is self-collected.
Figure 27.1: Distribution of flued versus unflued gas heating and age of wood burner, Auckland
Text description of figure
There are two pie graphs. The first graph shows the distribution of flued and unflued gas heaters. Unflued gas makes up 65% of all gas heating and Flued gas makes up 35%.
The second graph is divided by the age of wood burners. Post-1999 wood burners make up 32%, 1994-99 wood burners make up 27% and the remaining 41% of wood burners are Pre-1994.
Figure 27.2: Domestic heating method, by average monthly heating expenditure, house ownership, house age and number of bedrooms, Auckland
Average heating cost per month (winter)
Age of dwelling
Number of bedrooms
Text description of figure
There are four bar graphs.
The first graph sets out the average heating cost per month in winter. Cost per month by heating methods are: electric $69, gas $43, open fire $30, wood burner $57, pellet burner $0, multi-fuel $0 and oil $115.
The second graph sets out heating methods divided by home tenure. For households living in rentals 51523 use electric, 35253 use gas, 10847 use open fire, 8135 use wood burners, 0 use pellet burners, 5423 use multi-fuel and 2712 use oil. For households living in their own house 146434 use electricity, 108470 use gas, 18982 use open fires, 67794 use wood burners, 0 use pellet burners, 8135 use multi-fuel and 5423 use oil.
The third graph sets out the age of a dwelling using a particular method of heating.
- Heating methods for houses under 10 years old are 19% electric, 30% gas, 18% wood burners, 0% multi fuel and 9% open fires.
- Heating methods for houses between 11 and 20 years old are 15% electric, 11 gas, 11% wood burners, 20% multi fuel and 9% open fires.
- Heating methods for houses between 21 and 40 years old are 32% electric, 32% gas, 43% wood burners, 40% multi fuel and 18% open fires.
- Heating methods for houses over 41 years old are 23% electric, 13% gas, 21% wood burners, 0% multi fuel and 45% open fires.
The fourth graph sets out particular heating methods by the number of bedrooms.
- Heating methods for houses with one bedroom are 1% electricity, 0% gas, 0% wood burner, 0% multi fuel and 0% open fire.
- Heating methods for houses with two bedrooms are 18% electricity, 17% gas, 4% wood burner, 20% multi fuel and 18% open fire.
- Heating methods for houses with three bedrooms are 49% electricity, 43% gas, 64% wood burner, 40% multi fuel and 55% open fire.
- Heating methods for houses with four bedrooms are 19% electricity, 30% gas, 21% wood burner, 40% multi fuel and 27% open fire.
- Heating methods for houses with five bedrooms are 7% electricity, 9% gas, 4% wood burner, 0% multi fuel and 0% open fire.
- Heating methods for houses with six bedrooms are 1% electricity, 0% gas, 4% wood burner, 0% multi fuel and 0% open fire.
Figure 27.3: Proportions of fuel obtained free of charge versus bought, Auckland
Text description of figure
This bar graph shows the amount of wood either bought or collected free of charge by three different types of heating.
Those using open fires bought 40% of their fuel, those using wood burners bought 40% of their fuel and those using multi-fuel burners bought 62% of their fuel.
Oil column heaters were the commonest type of electric heating used in the main living area of houses in Auckland (Table 27.6). The survey suggests that, unlike other areas of New Zealand, heat pumps are not a popular electrical heating choice in Auckland. A number of houses used more than one type of electric heater in their main living area.
Data on home heating methods, by house ownership, are shown in Table 27.7.
Household insulation types and heating methods are shown in Tables 27.8 and 27.9. In Auckland only 57% of houses had ceiling insulation and around 44% had wall insulation. Around 23% of households were thought to have no forms of insulation.
Table 27.10 shows home heating method, by household income. The overall non-response rate was around 23%. This limits the interpretation of these data because there may be an income bias in the non-respondents.
Tables 27.11 and 27.12 show the relationship between heating methods and the age of the dwelling and number of bedrooms, respectively.