20 Ashburton

Survey details are shown in Table 20.1. 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 suggests a population decrease for Ashburton of 2% by 2021. [High, medium and low population projections were estimated by Statistics New Zealand. The value used is the medium population projection.]

Table 20.1: Summary survey data, Ashburton

20.1 Home heating methods and fuels

The Digipoll survey was used to collect information on home heating methods and fuels for Ashburton. These data were collected for the purpose of evaluating the impact of variations in heating methods on air quality in Ashburton, 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 Ashburton largely in tabular form, in the expectation that these results will be of value in other assessments (eg, emission inventory studies).

Tables 20.2 and 20.3 show domestic heating methods and fuels used for main living areas in Ashburton houses, and seasonal variations in heating behaviour. The commonest methods of heating the main living area in Ashburton were electricity (61%) and wood burners (47%). Many households used more than one method of heating in their main living area.

Table 20.2: Domestic home heating methods and fuels, Ashburton

Table 20.3 shows that around 3% of households using gas and 1% of households using wood burners heat their homes during January and February in Ashburton. A larger proportion (10% and 7% of these households) heat their houses during November. The quantities of fuel used per day during non-winter months was typically less than during the winter (Table 20.4). 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.

Table 20.3: Monthly variations in heating behaviour and fuel use, Ashburton

Table 20.4: Estimated daily fuel use, by season, Ashburton

20.2 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 Ashburton are presented in this section.

Figure 20.1 shows that the proportion of households using gas systems that are properly flued in Ashburton is around 43%. This compares to a national average of around 24%.

The amount spent on heating for a winter month, by heating method, is shown in Table 20.5. In Ashburton, household heating expenditure ranges from $70 to $110 per month, on average, for different heating methods.

Figure 20.2 shows the average heating costs, home ownership, age of dwelling and number of bedrooms for households in Ashburton. Only a small proportion (14%) of the respondents in Ashburton 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 20.3 shows that over 50% of the wood used on solid fuel burners in Ashburton is self-collected.

Figure 20.1: Distribution of flued versus unflued gas heating and age of wood burner, Ashburton

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 57% of all gas heating and Flued gas makes up 43%.

The second graph is divided by the age of wood burners. Post-1999 wood burners make up 27%, 1994-99 wood burners make up 25% and the remaining 48% of wood burner are Pre-1994.

Table 20.5: Average monthly heating costs (winter), Ashburton

Figure 20.2: Domestic heating method, by average monthly heating expenditure, house ownership, house age and number of bedrooms, Ashburton

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 $103, gas $89, open fire $74, wood burner $85, pellet burner $0, multi-fuel $67 and oil $111.

The second graph sets out heating methods divided by home tenure. For households living in rentals 598 use electric, 80 use gas, 160 use open fire, 199 use wood burners, 0 use pellet burners, 14 use multi-fuel and 0 use oil. For households living in their own house 3032 use electricity, 1157 use gas, 239 use open fires, 2593 use wood burners, 40 use pellet burners, 559 use multi-fuel and 239 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 18% electric, 13% gas, 10% wood burners, 20% multi fuel and 0% open fires.
• Heating methods for houses between 11 and 20 years old are 19% electric, 16% gas, 9% wood burners, 13% multi fuel and 10% open fires.
• Heating methods for houses between 21 and 40 years old are 33% electric, 26% gas, 20% wood burners, 7% multi fuel and 20% open fires.
• Heating methods for houses over 41 years old are 26% electric, 46% gas, 51% wood burners, 60% multi fuel and 70% open fires.

The fourth graph sets out particular heating methods by the number of bedrooms.

• Heating methods for houses with one bedroom are 3% electricity, 0% gas, 0% wood burner, 0% multi fuel and 0% open fire.
• Heating methods for houses with two bedrooms are 21% electricity, 10% gas, 13% wood burner, 7% multi fuel and 10% open fire.
• Heating methods for houses with three bedrooms are 54% electricity, 52% gas, 56% wood burner, 47% multi fuel and 60% open fire.
• Heating methods for houses with four bedrooms are 19% electricity, 35% gas, 29% wood burner, 40% multi fuel and 20% open fire.
• Heating methods for houses with five bedrooms are 3% electricity, 3% gas, 3% wood burner, 7% multi fuel and 10% 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 20.3: Proportions of fuel obtained free of charge versus bought, Ashburton

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 47% of their fuel, those using wood burners bought 34% of their fuel and those using multi-fuel burners bought 50% of their fuel.

Table 20.6: Type of electric heating, Ashburt

The commonest types of electric heater used in the main living area in Ashburton houses were heat pumps, which were used by 42% of households using electric heating (Table 20.6). 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 20.7.

Table 20.7: Home heating method, by house ownership, Ashburton

Household insulation types and heating methods are shown in Tables 20.8 and 20.9. Most houses had ceiling insulation and around 50% had wall insulation. Around 21% of houses had at least three types of insulation.

Table 20.10 shows home heating method, by household income. The overall non-response rate was around 32%. This limits the interpretation of these data because there may be an income bias in the non-respondents.

Table 20.8: House insulation summary statistics, Ashburton

Table 20.9: Degree of house insulation, by heating method, Ashburton

Table 20.10: Home heating method, by household income, Ashburton

Tables 20.11 and 20.12 show the relationship between heating methods and the age of the dwelling and number of bedrooms, respectively.

Table 20.11: Home heating method, by age of dwelling, Ashburton

Table 20.12: Home heating, method by number of bedrooms, Ashburton