A telephone survey of domestic heating methods and fuels for Alexandra was carried out by Digipoll in November and December 2004. This involved surveying 150 households within the 2001 census area unit (CAU) area of Alexandra.
Survey details are shown in Table 10.1. 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 decrease for Central Otago of 18% by 2021. [High, medium and low population projections were estimated by Statistics New Zealand. The value used is the medium population projection.] It is assumed that this population decrease also applies to the urban area of Alexandra.
Table 10.1: Summary survey data, Alexandra
10.1 Home heating methods and fuels
The Digipoll survey was used to collect information on home heating methods and fuels for Alexandra. These data were collected for the purpose of evaluating the impact of variations in heating methods on air quality in Alexandra, 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 Alexandra largely in tabular form, in the expectation that these results will be of value in other assessments (eg, emission inventory studies).
Tables 10.2 and 10.3 show domestic heating methods and fuels used for the main living areas in Alexandra houses, and seasonal variations in heating behaviour. Electricity and wood burners were the commonest methods of heating the main living areas of houses in Alexandra, with 59% and 47% of households, respectively, using these methods. Many households used more than one method of heating. Overall, 67% of households in Alexandra used wood and 9% used coal for heating in their main living areas.
Table 10.2: Domestic home heating methods and fuels, Alexandra
Only a small proportion of households in Alexandra heat their homes during the summer months (Table 10.3). Table 10.4 shows that daily fuel use per household is generally less during the non-winter months. No data on fuel use were provided for open fires because of the low response rate for this question.
Data shown in Table 10.3 exclude information relating to seasonal variations in electricity use for domestic heating. This is because this information was collected for the evaluation of emissions from domestic heating to determine options for reducing PM10 emissions in urban areas of New Zealand. Electricity is treated as a zero emission source for this purpose.
Table 10.3: Monthly variations in heating behaviour and fuel use, Alexandra
Table 10.4: Estimated daily fuel use, by season, Alexandra
10.2 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 Alexandra are presented in this section.
Figure 10.1 shows that in Alexandra around 29% of households using gas have flued gas systems. This is consistent with the national average (28%). The average amount spent on solid fuel methods in Alexandra ranges from $33 for open fires to $153 dollars per month for electric heating (Table 10.5).
Figure 10.2 shows the average heating costs, home ownership, age of dwelling and number of bedrooms for households in Alexandra. Wood burners and electricity were the main methods of heating the main living area in rented houses in Alexandra.
One factor influencing the amount spent on different heating methods is the ability for households using solid fuel burners to obtain wood free of charge. Figure 10.3 shows that less than half of the wood used for home heating in Alexandra is self-collected.
Figure 10.1: Distribution of flued versus unflued gas heating and age of wood burner, Alexandra
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 71% of all gas heating and Flued gas makes up 29%.
The second graph is divided by the age of wood burners. Post-1999 wood burners make up 22%, 1994-99 wood burners make up 29% and the remaining 49% of wood burner are Pre-1994.
Table 10.5: Average monthly heating costs (winter), Alexandra
Figure 10.2: Domestic heating method, by average monthly heating expenditure, house ownership, house age and number of bedrooms, Alexandra
Average heating cost per month (winter)
House ownership
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 $153, gas $118, open fire $33, wood burner $84, pellet burner $177, multi-fuel $72 and oil $145.
The second graph sets out heating methods divided by home tenure. For households living in rentals 109 use electric, 60 use gas, 12 use open fire, 109 use wood burners, 0 use pellet burners, 72 use multi-fuel and 12 use oil. For households living in their own house 965 use electricity, 169 use gas, 24 use open fires, 736 use wood burners, 12 use pellet burners, 253 use multi-fuel and 72 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 17% electric, 16% gas, 11% wood burners, 0% multi fuel and 33% open fires.
- Heating methods for houses between 11 and 20 years old are 21% electric, 26% gas, 14% wood burners, 26% multi fuel and 0% open fires.
- Heating methods for houses between 21 and 40 years old are 44% electric, 37% gas, 37% wood burners, 48% multi fuel and 0% open fires.
- Heating methods for houses over 41years old are 18% electric, 21% gas, 34% wood burners, 26% multi fuel and 67% open fires.
The fourth graph sets out particular heating methods by the number of bedrooms.
- Heating methods for houses with one bedroom are 2% electricity, 5% gas, 0% wood burner, 0% multi fuel and 0% open fire.
- Heating methods for houses with two bedrooms are 29% electricity, 11% gas, 4% wood burner, 7% multi fuel and 0% open fire.
- Heating methods for houses with three bedrooms are 48% electricity, 47% gas, 61% wood burner, 59% multi fuel and 67% open fire.
- Heating methods for houses with four bedrooms are 16% electricity, 37% gas, 29% wood burner, 30% multi fuel and 0% open fire.
- Heating methods for houses with five bedrooms are 4% electricity, 0% gas, 6% wood burner, 4% multi fuel and 33% open fire.
- Heating methods for houses with six bedrooms are 0% electricity, 0% gas, 0% wood burner, 0% multi fuel and 0% open fire.
Figure 10.3: Proportions of fuel obtained free of charge versus bought, Alexandra
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 50% of their fuel, those using wood burners bought 60% of their fuel and those using multi-fuel burners bought 60% of their fuel.
Table 10.6: Type of electric heating, Alexandra
The main types of electric heating used by households in their main living area in Alexandra were heat pumps and fan heaters, used by 40% and 24% of households using electric heating, respectively (Table 10.6). The proportion of houses with heat pumps is much higher than the national average (13% of households using electric heating in their main living area).
Detailed data on home heating method, by house ownership, are shown in Table 10.7.
Table 10.7: Home heating method, by house ownership, Alexandra
Household insulation types and heating methods are shown in Tables 10.8 and 10.9. Around 5% of houses in Alexandra are reported as having no insulation, which is lower than the national average of 10%. Table 10.10 shows home heating method, by household income. The overall non-response rate was around 17%. This limits the use of these data because there may be an income bias in the non-respondents.
Table 10.8: House insulation summary statistics, Alexandra
Table 10.9: Degree of house insulation, by heating method, Alexandra
Table 10.10: Home heating method, by household income, Alexandra
Tables 10.11 and 10.12 show the relationship between heating methods and the age of the dwelling and number of bedrooms, respectively.
Table 10.11: Home heating method, by age of dwelling, Alexandra
Table 10.12: Home heating method, by number of bedrooms, Alexandra
10 Alexandra
November 2005
© Ministry for the Environment