A telephone survey of domestic heating methods and fuels for Milton was carried out by Digipoll in December 2004. This involved surveying 150 households within the 2001 census area unit (CAU) areas of Milton.
Survey details are shown in Table 15.1. 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 Clutha District of 13% by 2021. [High, medium and low population projections were estimated by Statistics New Zealand. The value used is the medium population projection.] This decrease was assumed to apply to the urban area of Milton.
Table 16.1: Summary survey data, Milton
16.1 Home heating methods and fuels
The Digipoll survey was used to collect information on home heating methods and fuels for Milton. These data were collected for the purpose of evaluating the impact of variations in heating methods on air quality in Milton, 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 Milton largely in tabular form, in the expectation that these results will be of value in other assessments (eg, emission inventory studies).
Tables 16.2 and 16.3 show domestic heating methods and fuels used for main living areas in Milton houses, and seasonal variations in heating behaviour. The commonest methods of heating the main living area in Milton were electricity (43%), multi-fuel burners (39%) and wood burners (35%). Many households used more than one method of heating in their main living area.
Like Balclutha, the use of multi-fuel burners in Milton was higher than average at 39%, compared with a national average of 8%. In contrast to Balclutha, however, the main solid fuel source in Milton is wood (77%).
Table 16.2: Domestic home heating methods and fuels, Milton
At least 10% of the households using solid fuel burning for domestic home heating operated them during the non-winter months, generally burning on around five days a week. Gas was also used for heating during the summer months by around 9% of the households using that method. The quantities of fuel used per day during the non-winter months were less than during the winter (Table 16.4). 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 16.3: Monthly variations in heating behaviour and fuel use, Milton
Table 16.4: Estimated daily fuel use, by season, Milton
16.2 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 Milton are presented in this section.
Figure 16.1 shows that the proportion of households using gas systems that are properly flued in Milton is similar to the national average (23% in Milton compared with 28% in the national survey). The proportion of wood burners that were thought to be more than 10 years old was slightly greater than average at 53% compared with 43% nationally.
The amount spent on heating for a winter month, by heating method, is shown in Table 16.5. With the exception of households using electricity and open fires, which spend almost twice as much as some other methods, the monthly fuel costs do not vary significantly with heating method in Milton.
Figure 16.2 shows the average heating costs, home ownership, age of dwelling and number of bedrooms for households in Milton. 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 16.3 shows that around half of the wood used on wood burners and open fires in Milton is self-collected, compared with around 70% for multi-fuel burners.
Figure 16.1: Distribution of flued versus unflued gas heating and age of wood burner, Milton
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 77% of all gas heating and Flued gas makes up 23%.
The second graph is divided by the age of wood burners. Post-1999 wood burners make up 14%, 1994-99 wood burners make up 33% and the remaining 63% of wood burner are Pre-1994.
Table 16.5: Average monthly heating costs (winter), Milton
Figure 16.2: Domestic heating method, by average monthly heating expenditure, house ownership, house age and number of bedrooms, Milton
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 $122, gas $59, open fire $122, wood burner $65 and multi-fuel $62.
The second graph sets out heating methods divided by home tenure. For households living in rentals 45 use electric, 30 use gas, 10 use open fire, 35 use wood burners, 0 use pellet burners, 50 use multi-fuel and 0 use oil. For households living in their own house 282 use electricity, 146 use gas, 20 use open fires, 227 use wood burners, 5 use pellet burners, 242 use multi-fuel and 15 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 15% electric, 6% gas, 13% wood burners, 2% multi fuel and 0% open fires.
- Heating methods for houses between 11 and 20 years old are 11% electric, 3% gas, 13% wood burners, 7% multi fuel and 0% open fires.
- Heating methods for houses between 21 and 40 years old are 26% electric, 29% gas, 17% wood burners, 31% multi fuel and 17% open fires.
- Heating methods for houses over 41years old are 42% electric, 60% gas, 50% wood burners, 52% 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 3% electricity, 0% gas, 0% wood burner, 2% multi fuel and 0% open fire.
- Heating methods for houses with two bedrooms are 29% electricity, 17% gas, 19% wood burner, 10% multi fuel and 17% open fire.
- Heating methods for houses with three bedrooms are 51% electricity, 57% gas, 50% wood burner, 62% multi fuel and 50% open fire.
- Heating methods for houses with four bedrooms are 14% electricity, 17% gas, 23% wood burner, 14% multi fuel and 17% open fire.
- Heating methods for houses with five bedrooms are 2% electricity, 6% gas, 2% wood burner, 9% multi fuel and 17% open fire.
- Heating methods for houses with six bedrooms are 2% electricity, 3% gas, 0% wood burner, 0% multi fuel and 0% open fire.
Figure 16.3: Proportions of fuel obtained free of charge versus bought, Milton
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 54% of their fuel and those using multi-fuel burners bought 28% of their fuel.
Table 16.6: Type of electric heating, Milton
Heat pumps were the most common method of electric heating for houses in Milton, with around 31% of households using electricity in the main living area having a heat pump (Table 16.6). This is much higher than the national average (13%). Portable oil column heaters were also common (20%).
Data on home heating methods, by house ownership, are shown in Table 16.7.
Table 16.7: Home heating method, by house ownership, Milton
Household insulation types and heating methods are shown in Tables 16.8 and 16.9. The proportion of households that were thought to have no insulation (13%) was similar to the national average (10%).
Table 16.10 shows home heating method, by household income. The overall non-response rate was around 29%. This limits the interpretation of these data because there may be an income bias in the non-respondents.
Table 16.8: House insulation summary statistics, Milton
Table 16.9: Degree of house insulation, by heating method, Milton
Table 16.10: Home heating method, by household income, Milton
Tables 16.11 and 16.12 show the relationship between heating methods and the age of the dwelling and number of bedrooms, respectively.
Table 16.11: Home heating method, by age of dwelling, Milton
Table 16.12: Home heating method, by number of bedrooms, Milton
16 Milton
November 2005
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