A telephone survey of domestic heating methods and fuels for Oamaru was carried out by Digipoll in November 2004. This involved surveying 150 households within the 2001 census area unit (CAU) area of Oamaru North, Orana Park, Oamaru Central and Oamaru South.
Survey details are shown in Table 11.1. 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 the Waitaki District of 17% 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 decrease applies to the urban area of Oamaru.
Table 11.1: Summary survey data, Oamaru
11.1 Home heating methods and fuels
The Digipoll survey was used to collect information on home heating methods and fuels for Oamaru. These data were collected for the purpose of evaluating the impact of variations in heating methods on air quality in Oamaru, 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 Oamaru largely in tabular form, in the expectation that these results will be of value in other assessments (eg, emission inventory studies).
Tables 11.2 and 11.3 show domestic heating methods and fuels used for main living areas in Oamaru houses, and seasonal variations in heating behaviour. Electricity and wood burners were the commonest methods of heating in Oamaru, with 47% and 57% of households using these methods, respectively. Many households used more than one method of heating in their main living area. Overall, 79% of households in Oamaru used wood and 13% used coal for heating in their main living areas.
Table 11.2: Domestic home heating methods and fuels, Oamaru
Table 11.3 shows that around 4% of households using wood burners for heating heat their homes during the summer months, burning on average three days per week during January and February. Data shown in Table 11.3 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 11.4 shows that while daily fuel use per household is generally less during the non-winter months, the amount of coal used on an open fire is actually higher than during the winter months. This does not suggest that any given household uses more fuel during summer than during winter, as fewer households reported coal use on open fires during the non-winter months and these houses burnt more than the average amount of coal during the winter months. Data are not presented for all heating methods, because the number of respondents for methods such as oil and pellet burners was small.
Table 11.3: Monthly variations in heating behaviour and fuel use, Oamaru
Table 11.4: Estimated daily fuel use, by season, Oamaru
11.2 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 Oamaru are presented in this section.
Figure 11.1 shows that in Oamaru around 32% of households using gas have flued gas systems.
The average amount spent on fuel for solid fuel methods in Oamaru ranged from $43 for open fires to $135 dollars per month for multi-fuel burners (Table 11.5).
Figure 11.2 shows the average heating costs, home ownership, age of dwelling and number of bedrooms for households in Oamaru. This shows that larger houses in Oamaru typically use an open fire or gas for heating the main living area, and that electricity or wood burners are the most common forms of heating in rental properties.
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 11.3 shows that over half of the wood used for home heating in Oamaru is self-collected.
Figure 11.1: Distribution of flued versus unflued gas heating and age of wood burner, Oamaru
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 68% of all gas heating and Flued gas makes up 32%.
The second graph is divided by the age of wood burners. Post-1999 wood burners make up 22%, 1994-99 wood burners make up 33% and the remaining 45% of wood burner are Pre-1994.
Table 11.5: Average monthly heating costs (winter), Oamaru
Figure 11.2: Domestic heating method, by average monthly heating expenditure, house ownership, house age and number of bedrooms, Oamaru
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 $90, gas $70, open fire $43, wood burner $79 and multi-fuel $135.
The second graph sets out heating methods divided by home tenure. For households living in rentals 399 use electric, 153 use gas, 92 use open fire, 460 use wood burners, 0 use pellet burners, 92 use multi-fuel and 0 use oil. For households living in their own house 1749 use electricity, 675 use gas, 184 use open fires, 2148 use wood burners, 31 use pellet burners, 675 use multi-fuel and 31 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 11% electric, 0% gas, 9% wood burners, 8% multi fuel and 0% open fires.
- Heating methods for houses between 11 and 20 years old are 10% electric, 0% gas, 8% wood burners, 8% multi fuel and 0% open fires.
- Heating methods for houses between 21 and 40 years old are 24% electric, 33% gas, 21% wood burners, 20% multi fuel and 11% open fires.
- Heating methods for houses over 41years old are 47% electric, 59% gas, 55% wood burners, 64% 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, 0% multi fuel and 0% open fire.
- Heating methods for houses with two bedrooms are 26% electricity, 19% gas, 7% wood burner, 0% multi fuel and 22% open fire.
- Heating methods for houses with three bedrooms are 53% electricity, 48% gas, 60% wood burner, 52% multi fuel and 33% open fire.
- Heating methods for houses with four bedrooms are 16% electricity, 30% gas, 32% wood burner, 44% multi fuel and 11% open fire.
- Heating methods for houses with five bedrooms are 1% electricity, 0% gas, 0% wood burner, 4% multi fuel and 11% open fire.
- Heating methods for houses with six bedrooms are 1% electricity, 4% gas, 0% wood burner, 0% multi fuel and 22% open fire.
Figure 11.3: Proportions of fuel obtained free of charge versus bought, Oamaru
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 32% of their fuel and those using multi-fuel burners bought 33% of their fuel.
Table 11.6: Type of electric heating, Oamaru
The main types of electric heaters used by households in their main living area in Oamaru were heat pumps and fan heaters, both used by 26% of households using electric heating (Table 11.6). At 26% 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, by house ownership, are shown in Table 11.7.
Table 11.7: Home heating method, by house ownership, Oamaru
Household insulation types and heating methods are shown in Tables 11.8 and 11.9. Around 13% of houses in Oamaru report having no insulation. Table 11.10 shows home heating method, by household income. The overall non-response rate was around 21%. This limits the use of these data because there may be an income bias in the non-respondents.
Table 11.8: House insulation summary statistics, Oamaru
Table 11.9: Degree of house insulation, by heating method, Oamaru
Table 11.10: Home heating method, by household income, Oamaru
Tables 11.11 and 11.12 show the relationship between heating methods and the age of the dwelling and number of bedrooms, respectively.
Table 11.11: Home heating method, by age of dwelling, Oamaru
Table 11.12: Home heating method, by number of bedrooms, Oamaru
11 Oamaru
November 2005
© Ministry for the Environment