13 Cromwell
A telephone survey of domestic heating methods and fuels for Cromwell was carried out by Digipoll in November 2004. This involved surveying 151 households within the 2001 census area unit (CAU) area of Cromwell.
Survey details are shown in Table 13.1. 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 Central Otago District 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 decrease applies to the urban area of Cromwell.
Table 13.1: Summary survey data, Cromwell
13.1 Home heating methods and fuels
The Digipoll survey was used to collect information on home heating methods and fuels for Cromwell. These data were collected for the purpose of evaluating the impact of variations in heating methods on air quality in Cromwell, 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 Cromwell largely in tabular form, in the expectation that these results will be of value in other assessments (eg,emission inventory studies).
Tables 13.2 and 13.3 show domestic heating methods and fuels used for main living areas in Cromwell houses, and seasonal variations in heating behaviour. Electricity and wood burners were the commonest methods of heating the main living areas of houses in Cromwell, with 47% and 56% of households (respectively) using this method. Multi-fuel burner use was also quite high at 25%. Many households used more than one method of heating in their main living area. Overall, 84% of households in Cromwell used wood and 19% used coal for heating in their main living areas.
Table 13.2: Domestic home heating methods and fuels, Cromwell
Table 13.3 shows that only a small proportion of households heat their homes during the summer in Cromwell. Data shown in Table 13.3 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.
The average daily fuel use per household during the non-winter months is generally less than the amount used per day during the winter (Table 13.4). 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 13.3: Monthly variations in heating behaviour and fuel use, Cromwell
Table 13.4: Estimated daily fuel use, by season, Cromwell
13.2 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 Cromwell are presented in this section.
Figure 13.1 shows that in Cromwell around 25% of households using gas have flued gas systems.
The average amount spent on fuel for solid fuel methods in Cromwell ranges from $91 for wood burners to $176 per month for multi-fuel burners. These values are generally higher than the national average values, which range from $60 to $70 for gas and solid fuel heating methods and $117 per month for electricity.
The average heating costs, home ownership, age of dwelling and number of bedrooms for households in Cromwell are shown in Figure 13.2.
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 13.3 shows that around half of the wood used for home heating in Cromwell is self-collected.
Figure 13.1: Distribution of flued versus unflued gas heating and age of wood burner, Cromwell
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 75% of all gas heating and Flued gas makes up 25%.
The second graph is divided by the age of wood burners. Post-1999 wood burners make up 40%, 1994-99 wood burners make up 26% and the remaining 34% of wood burner are Pre-1994.
Table 13.5: Average monthly heating costs (winter), Cromwell
Figure 13.2: Domestic heating method, by average monthly heating expenditure, house ownership, house age and number of bedrooms, Cromwell
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 $137, gas $112, open fire $118, wood burner $91 and multi-fuel $176.
The second graph sets out heating methods divided by home tenure. For households living in rentals 65 use electric, 29 use gas, 14 use open fire, 129 use wood burners, 0 use pellet burners, 43 use multi-fuel and 0 use oil. For households living in their own house 445 use electricity, 115 use gas, 29 use open fires, 473 use wood burners, 7 use pellet burners, 222 use multi-fuel and 29 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 34% electric, 10% gas, 30% wood burners, 11% multi fuel and 33% open fires.
- Heating methods for houses between 11 and 20 years old are 20% electric, 20% gas, 17% wood burners, 30% multi fuel and 0% open fires.
- Heating methods for houses between 21 and 40 years old are 23% electric, 50% gas, 27% wood burners, 41% multi fuel and 33% open fires.
- Heating methods for houses over 41years old are 20% electric, 15% gas, 24% wood burners, 16% multi fuel and 33% 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 10% electricity, 10% gas, 5% wood burner, 3% multi fuel and 17% open fire.
- Heating methods for houses with three bedrooms are 61% electricity, 60% gas, 60% wood burner, 62% multi fuel and 50% open fire.
- Heating methods for houses with four bedrooms are 21% electricity, 30% gas, 30% wood burner, 35% multi fuel and 0% open fire.
- Heating methods for houses with five bedrooms are 4% electricity, 0% gas, 5% wood burner, 0% 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 13.3: Proportions of fuel obtained free of charge versus bought, Cromwell
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 50% of their fuel and those using multi-fuel burners bought 48% of their fuel.
Table 13.6: Type of electric heating, Cromwell
The main types of electric heating used by households in their main living area in Cromwell were heat pumps and fan heaters, which were used by 41% and 27% of households using electric heating, respectively. 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 for home heating method, by house ownership, are shown in Table 13.7.
Table 13.7: Home heating method, by house ownership, Cromwell
Household insulation types and heating methods are shown in Tables 13.8 and 13.9. Around 6% of houses in Cromwell report no insulation. Table 13.10 shows home heating method, by household income. Results suggest a large proportion of households using open fires in Cromwell had incomes greater than $50,000. Results for other heating methods are difficult to interpret because of the non-response rate (19% overall).
Table 13.8: House insulation summary statistics, Cromwell
Table 13.9: Degree of house insulation, by heating method, Cromwell
Table 13.10: Home heating method, by household income, Cromwell
Tables 13.11 and 13.12 show the relationship between heating methods and the age of the dwelling and number of bedrooms, respectively.
