BRANZ HEEP Final Report - Table of Contents

Household Energy End-Use Project - Final report. Table of contents only.


[Guide to index, illustrations, figures, and tables]

[Document index]

1 INTRODUCTION 1
1.1 HEEP monitoring overview 1
1.2 HEEP in action 3
1.3 Further information  5
1.4 Acknowledgements 5

2 ENERGY END-USES 7
2.1 Changes in electricity use since 1971/72  7
2.2 Energy use distribution 10
2.3 Patterns of energy use  12
2.4 Energy consumption over the year  17
2.5 Appliance electricity use 18
2.6 Lighting  20
2.7 Changing official New Zealand energy statistics  21

3 HOUSEHOLD SELECTION  23
3.1 Sample size 23
3.2 Methodology  23
3.3 Participation rate 24
4 MONITORING AND DATA 28
4.1 What HEEP measured  28
4.2 Installation of monitoring equipment  29
4.3 Removal of equipment  30
4.4 Personnel and travel  30
4.5 Data collection equipment  31
4.6 Data processing  32
4.7 Specific fuel type processing  34
4.8 Data reliability  36
4.9 Meteorological data 39
4.10 Survey data 39

5 SAMPLE STRUCTURE AND ESTIMATION METHODS 42
5.1 General comments on bias 42
5.2 Large scale sample structure  42
5.3 Effect of spreading the survey over time 43
5.4 General principles of estimation  43
5.5 Monitoring within houses  44
5.6 Sampling of appliances for transponder monitoring 45
5.7 Estimation within houses  46
5.8 Application of the method in practice 47
5.9 The estimation technique in practice  50
6 HEERA MODEL DEVELOPMENT  54
6.1 Overview  54
6.2 Database design 55
6.3 HEERA Model 55
6.4 Excel and Access database tables  68
6.5 Graphic User Interface forms and VB procedures 69
6.6 Demonstration  69

7 WINTER TEMPERATURES 70
7.1 Historical comparison  70
7.2 Climate  71
7.3 Temperature distribution  72
7.4 Reported heating schedules by occupants  73
7.5 Reported heating seasons  76
7.6 Monitored heating seasons 78
7.7 House age 85
7.8 Thermal insulation  86
7.9 Temperature stratification 88
7.10 Winter temperature discussion  90

8 SUMMER TEMPERATURES 92
8.1 Maximum temperatures  94
8.2 Influences on indoor temperatures 96
8.3 Model of summer living room temperatures 98
8.4 Why are new houses warmer? 99
8.5 Temperature stratification in summer  101
8.6 Summer temperature discussion 101

9 EXTENSIVE TEMPERATURE MONITORING IN ONE HOUSE – CASE STUDY  103
9.1 The chosen typical house  103
9.2 Experimental set-up  103
9.3 Results 104
9.4 Vertical temperature distribution  106
9.5 Conclusions 108

10 PENSIONER HOUSING – TEMPERATURE CASE STUDY 109
10.1 Temperatures  109
10.2 Conclusions from the Hamilton study  111

11 SOCIAL ANALYSIS - INTRODUCTION 112

12 SOCIO-DEMOGRAPHIC CHARACTERISTICS OF HEEP HOUSEHOLDS 113
12.1 Household type 113
12.2 Household income  114

13 HOUSEHOLD VARIABLES AND FORECASTING AGGREGATE ENERGY USE 116
13.1 Income, living room temperatures and energy use  116
13.2 Size of household, living room temperatures and energy use 118
13.3 Household life stage, temperatures and energy use  120
13.4 The impact of social variables  121

14 FUEL POVERTY, MAORI HOUSEHOLDS AND SOLID FUEL USAGE  123
14.1 Fuel poverty  123
14.2 Temperature and energy use in Māori households  126
14.3 Impacts on Vulnerable Households of Moving Away from Solid Fuel  132
14.4 Energy and social policy – a critical interface  139

15 HOT WATER HEATING, DWELLING SIZE AND SUSTAINABILITY  141
15.1 Hot water heating – the shift to gas 141
15.2 House size, energy use and sustainability  147
16 MEASURING ENERGY USE IN WOOD AND SOLID FUEL HEATING 153
16.1 Introduction 153
16.2 Method 154
16.3 Comparison with Modera’s Equation 158
16.4 Results 159
16.5 Conclusions 160

17 LPG HEATER USE  162
17.1 Background  162
17.2 Heater numbers  162
17.3 Heater types 164
17.4 Data availability  165
17.5 Sample LPG heater use patterns 167
17.6 Patterns of use 169
17.7 LPG heater and dehumidifier ownership 173

18 EFFECT OF MANDATORY INSULATION ENERGY CONSUMPTION  174
18.1 Introduction and review 174
18.2 Household data 175
18.3 Statistical models of space heating 177
18.4 Summary of model results and discussion  180
18.5 Conclusions 181

19 ESTIMATING HEAT LOSS AND THERMAL MASS  182
19.1 STEM thermal model  182
19.2 Using STEM on HEEP houses in general  182
19.3 The STEM Model for a discrete time-series  184
19.4 Estimation of energy loads 185
19.5 Calibration by prediction of internal temperatures  185
19.6 STEM prediction  185
19.7 STEM results 186
19.8 Practical use of STEM model for HEEP analyses  187

20 HEEP APPLIANCE OWNERSHIP MODELS  188
20.1 Ownership data 188
20.2 Methods 188
20.3 Overview of models 189
20.4 Entertainment equipment 193

21 STANDBY AND BASELOAD IN NEW ZEALAND HOUSES  195
21.1 Introduction 195
21.2 Review  196
21.3 Standby & baseload data 196
21.4 Methodology  197
21.5 Results 199
21.6 Conclusions  202

22 FAULTY REFRIGERATION APPLIANCES  203
22.1 Review 203
22.2 Appliance data  204
22.3 Methodology  207
22.4 Results  208
22.5 Testing Cavallo and Mapp algorithm  209
22.6 Energy waste from faulty refrigeration appliances  210
22.7 Implications for energy savings programs  211
22.8 Greenhouse gas emissions 211
22.9 Discussion and conclusions 211

23 LOAD FACTORS AND REACTIVE POWER  213
23.1 Load factors  213
23.2 Reactive power  215
23.3 Measured reactive power and power factor  216

24 DOMESTIC HOT WATER 221
24.1 Introduction 221
24.2 Hot water today  221
24.3 Providing domestic hot water 222
24.4 International comparisons  224
24.5 Hot water Energy Use  228
24.6 DHW energy use distribution 230
24.7 System types  241
24.8 Estimates of wet-back energy heat inputs  243
24.9 Storage cylinders  244
24.10 Baths and showers 254
24.11 Shower water flow 258
24.12 Water temperatures 260
24.13 Improving cylinder thermal performance 269
24.14 Costs 270
24.15 Improving cylinder electricity efficiency  271
24.16 Cylinder wraps in reality  274
24.17 Reducing hot water energy use 275
24.18 Conclusions 276

25 ENERGY USE OF HEEP HOUSES COMPARED TO ALF3  278
25.1 Modelling  278
25.2 Selection criteria 278
25.3 ALF3 heating energy estimates 278
25.4 Heating temperature 281
25.5 Modelling issues 284
25.6 HEEP heating energy estimates  290
25.7 Comparison of energy use  291
25.8 Conclusions  296

26 REFERENCES  297
26.1 HEEP reports 297
26.2 HEEP BUILD articles 298
26.3 HEEP conference papers  298
26.4 HEEP Journal Papers  300
26.5 Other HEEP references 300
26.6 References 301

APPENDIX 1: TABLE OF STANDBY POWER AND ENERGY  310
APPENDIX 2: ENERGY CONSUMPTION TABLES  311
APPENDIX 3: ESTIMATES OF PRECISION IN MULTI-STAGE SURVEYS 312
APPENDIX 4: SAMPLING VARIANCE OF THE SURVEY ESTIMATOR 314
APPENDIX 5: EXAMPLE OF BIAS ARISING THROUGH FAILURE TO TAKE ACCOUNT OF VARYING PROBABILITIES OF SELECTION WITHIN HOUSES  318

APPENDIX 6: HISTORICAL REVIEW OF HOT WATER 319
Until piped water 322
Beginnings of piped hot water  325
History of electric hot water 326
History of gas hot water  329

APPENDIX 7: CENSUS DHW QUESTIONS  333

APPENDIX 8: INTERNATIONAL REVIEW OF SHOWER WATER FLOW RATES  334
New Zealand  334
America 334
Australia  335
United Kingdom  336

APPENDIX 9: PENSIONERS HOT WATER USE  337
Hot water energy demand  337
Standing loss determined by tap temperatures 338
Conclusions  339

APPENDIX 10: DHW STANDING LOSSES CALCULATION 340
Initial standing loss estimation methods  340

APPENDIX 11: DHW WET-BACK (SUPPLEMENTARY) WATER HEATING 347
Introduction 347
Calibration of wet-back systems  347

[Figures and illustrations]

Figure 1: Map of New Zealand showing HEEP monitoring locations  2
Figure 2: A power station was hiding in the wood shed  3
Figure 3: Theme illustrations from the HEEP Year 10 celebration  4
Figure 4: Electricity use per household 1946-2005  8
Figure 5: Electricity uses 1971/72 8,400 kWh pa  9
Figure 6: Electricity uses HEEP 7,240 kWh pa  9
Figure 7: Energy use distribution – all fuels  10
Figure 8: Energy use distribution – electricity  12
Figure 9: Energy use distribution – gas (natural gas & large bottle LPG)  12
Figure 10: Energy use distribution – LPG (small bottles)  12
Figure 11: Energy use distribution – Solid fuel  12
Figure 12: Regional patterns of energy end-uses  13
Figure 13: Total energy use by fuel type  15
Figure 14: Total energy use by end-use  15
Figure 15: Space heating gross energy by fuel  16
Figure 16: Space heating delivered energy by fuel  16
Figure 17: Energy use by end-use and month  17
Figure 18: Electric appliances  20
Figure 19: Average monthly lighting power – all NZ  21
Figure 20: Fuels all end-uses (Dec yr 2004)  22
Figure 21: Fuels all end-uses (Sept yr 2005)  22
Figure 22: Participation rate of households taking part in HEEP  25
Figure 23: Regional participation rate by urban level  26
Figure 24: Schematic of HEEP data processing  33
Figure 25: A section of a prepro file  33
Figure 26: Sample EDA plots for two temperature sensors  36
Figure 27: HEERA modelling framework  55
Figure 28: HEERA flow diagram with representative tables, algorithms and forms  55
Figure 29: Contribution of new dwellings to the stock of dwellings  60
Figure 30: Net dwelling stock growth over the period 1850 to 2070  64
Figure 31: Building consents (1974 to 2003) compared to vintage stock model  64
Figure 32: New dwelling survival function  65
Figure 33: Probability of new dwelling stock retirement function  65
Figure 34: National dwelling stock by insulation level  68
Figure 35: Mean winter evening living room and ambient temperature by Regional Council 71
Figure 36: Mean winter night time bedroom temperature by Regional Council  72
Figure 37: Distribution of winter evening living room temperatures  72
Figure 38: Living room daytime heating by region and weekday/weekend  74
Figure 39: Heating index by region  74
Figure 40: Bedroom overnight heating by region and weekday/weekend  74
Figure 41: Living room 24 hour heating by region  75
Figure 42: Reported heating season start and finish  77
Figure 43: Length of reported heating season  77
Figure 44: Example – LPG heater use  79
Figure 45: Example – solid fuel use  79
Figure 46: Non-hot water electricity use for one house  80
Figure 47: Months of heating – start and finish  81
Figure 48: Length of heating season  81
Figure 49: External temperature and energy use during heating season  82
Figure 50: Average external temperature for heating season  83
Figure 51: External temperatures of heating start and finish months  83
Figure 52: Living room evening temperature by location and most used heating fuel  85
Figure 53: Winter evening living room temperatures by year built  86
Figure 54: Regional living room temperature differences by insulation requirements  87
Figure 55: Regional bedroom temperature differences by insulation requirements  88
Figure 56: Relationship between temperature difference from the high and low loggers and the difference between outside and inside (linear fit line)  90
Figure 57: Mean living room temperatures  92
Figure 58: Time spent at given temperature ranges  93
Figure 59: Living and bedroom temperature distribution for morning and day  94
Figure 60: Time of maximum living room temperature by Regional Council  95
Figure 61: Maximum living room temperature by Regional Council  96
Figure 62: Mean living room daytime temperatures by Regional Council  97
Figure 63: Summer temperatures by house age  98
Figure 64: Mean living room temperature by airtightness  100
Figure 65: Glazing to wall area ratio by decade house built  100
Figure 66: Solar glazing ratio vs Auckland living room temperatures  101
Figure 67: Palmerston North House  103
Figure 68: Measured parameters  104
Figure 69: Average daily profile  105
Figure 70 Vertical temperature stratification, 1999 (living room south-east corner)  106
Figure 71: Vertical temperature profile, 2000 (living room south-east corner)  107
Figure 72 Hamilton pensioner family room evening temperatures  110
Figure 73 Hamilton non-pensioner family room evening temperatures  110
Figure 74: HEEP and 2001 Census and 2006 Household Composition  113
Figure 75: Age of youngest HEEP household member  114
Figure 76: Equivalised HEEP household income by youngest household member  115
Figure 77: Total fuel use by age of youngest household member HEEP households  120
Figure 78: Winter evening living room average temperature distribution  124
Figure 79: Household composition – HEEP & 2001 Census  127
Figure 80: Age of youngest household member – all & Māori HEEP households  128
Figure 81: Equivalised household income – all & Māori HEEP households  129
Figure 82: Winter evening living room temp – all & Māori HEEP households  130
Figure 83: Total gross annualised energy use for all & Māori HEEP households  131
Figure 84: Total gross annualised heating energy use for all & Māori HEEP households  132
Figure 85: Energy Use Groups vs Dwelling Size  151
Figure 86: Test calibration of gas heated house – House 1  156
Figure 87: Solid fuel calibration graphs (House 2)  157
Figure 88: Equation 15 heat output  159
Figure 89: HEEP estimates and Equation 15  159
Figure 90: LPG heaters per household in city and small town/rural areas  163
Figure 91: Gross energy output for each setting for radiant non-thermostat LPG heaters  165
Figure 92: LPG setting determination for one heater  165
Figure 93:LPG heater use by time of day & day of year (Houses 2 & 4)  168
Figure 94: LPG heater use by time of day & day of year (Houses 1 & 5)  169
Figure 95: Histogram of hours of use LPG heaters (winter months)  171
Figure 96: Histogram of the energy use for LPG heaters (winter months)  171
Figure 97: Proportion of the time spent in the primary settings for LPG heater  171
Figure 98: Expected gas consumption for the 'on' setting for each LPG heater  171
Figure 99: Energy used by each setting for heaters with winter usage  172
Figure 100: Time in each setting for heaters with winter usage  172
Figure 101: Cumulative plot of the energy used by each LPG heater  172
Figure 102: Wintertime LPG heater energy use (in kWh per week) for a number of areas around New Zealand  173
Figure 103: Total house heat loss for pre- and post-1978 houses  176
Figure 104: Heat loss per m² for pre- and post-1978 houses  176
Figure 105: Fitted model plots  184
Figure 106: STEM model results  186
Figure 107: Long-term stock levels of home entertainment appliances  193
Figure 108 Fridge power use histogram  197
Figure 109: Breakdown of standby energy per house by appliance group  200
Figure 110: 10 minute time series of refrigeration appliance power  205
Figure 111: Faulty freezer – 10 minute time series  206
Figure 112: Fridge freezer 10 min time series – cycles <20 min but not faulty  207
Figure 113: Energy use of new frost-free fridge freezers 1980-2006  212
Figure 114: Power factors for monitored houses - Hamilton, Wanganui and Wellington  214
Figure 115: Load curves for different HEEP locations  214
Figure 116: Household daily average real and reactive power and power factor  217
Figure 117: Histograms of the 10 minute power factors by household  217
Figure 118: Mean real and reactive components for each household  218
Figure 119: Real vs reactive power by household  218
Figure 120: House 1 summer day – real & reactive power, power factor  219
Figure 121: House 6 summer day – real & reactive power, power factor  219
Figure 122: Average daily profiles by house – real and reactive power, power factor  220
Figure 123: Examples of hot water cylinders  223
Figure 124: Residential use of storage electric hot water systems  225
Figure 125: Selected nations - electric hot water cylinders by capacity  227
Figure 126: DHW Fuels  228
Figure 127: Variation in proportions of energy end-uses  229
Figure 128: Variation in energy end-uses  229
Figure 129: DHW Energy use distribution – all fuels  230
Figure 130: DHW electricity distribution  232
Figure 131: DHW gas distribution  232
Figure 132: DHW Wetback distribution  232
Figure 133: Average DHW energy profiles  232
Figure 134: Monthly hot water energy profiles  232
Figure 135: National Hot Water Energy Use by Month  233
Figure 136: DHW Energy use by month  233
Figure 137: DHW Energy Use by Month for Houses with that fuel  234
Figure 138: Changing estimates of NZ residential energy end-uses  235
Figure 139: Energy consumption and standing losses by system type  238
Figure 140: Hot water systems – by type and houses  242
Figure 141: Cylinder volumes  245
Figure 142: Cylinder size by region  246
Figure 143: Cylinder size by age  246
Figure 144: NZ Sales by capacity of electric DHW cylinders 2004/5  247
Figure 145: System pressure by region  248
Figure 146: Pressure by house decades  248
Figure 147: Pressure by cylinder decades  248
Figure 148: System age by location  250
Figure 149: 135 and 180 litre cylinders by decade of manufacture  251
Figure 150: Cylinder manufacture compared to house construction decade  251
Figure 151:Total hot water volume vs floor area  253
Figure 152: Total hot water volume vs number of occupants  253
Figure 153: Single electric DHW systems – litres per person  253
Figure 154: Use of baths and showers 1971/72  255
Figure 155: Use of baths and showers HEEP  255
Figure 156: Household DHW volume 1971/72  256
Figure 157: Household DHW volume HEEP  256
Figure 158: Self-reported shower duration – histogram  257
Figure 159: Tap temperature by system type  261
Figure 160: Distribution of hot water tap temperature by electric cylinder volume  262
Figure 161: Variation between thermostat setting & delivered water temperature  264
Figure 162: Adult skin (full thickness) epidermal burn time  266
Figure 163: Hot water temperature vs occupant average age  267
Figure 164: Thermostat setting distribution  267
Figure 165: Tap temperature distribution  267
Figure 166: Thermostat setting vs tap hot water temperature  268
Figure 167: Negawatt cylinder wrap  270
Figure 168: Examples of electric hot water cylinder wraps  275
Figure 169: ALF3 screen image  279
Figure 170: Daily profile of inside temperatures and energy use – weekend  281
Figure 171: Daily profile of inside temperatures and energy use – weekday  281
Figure 172: Winter temperature profiles for Christchurch HEEP houses  282
Figure 173: HEEP sample mean average winter evening temperatures  283
Figure 174: Histogram of living room evening temperatures in selected sample  284
Figure 175: Cumulative frequency of living room temperatures in selected sample  284
Figure 176: Wind exposure classes  287
Figure 177: Percentage versus modelled heated zone methods  289
Figure 178: Average living room temperatures during heating times  292
Figure 179: ALF3 vs reality – 20% lines  293
Figure 180: ALF3 vs reality – 2000 kWh lines  293
Figure 181: Average house temperatures during measured heating times  294
Figure 182: ALF3 vs reality – 20% lines  295
Figure 183: ALF3 vs reality – 2000 kWh lines  295
Figure 184: NZ Census 1945-1996 Domestic Hot Water by fuel type  319
Figure 185: NZ Census 1945-1996 % Dwellings with no DHW  319
Figure 186: NZ Census 1976-1996 Dwellings with only one DHW fuel  320
Figure 187: 1981 Census DHW Fuels  321
Figure 188: 1996 Census DHW Fuels  321
Figure 189: Changes in reported DHW fuel by region  321
Figure 190: First Class Hotel 1899  322
Figure 191: 1930s Laundry Copper  324
Figure 192: Chip heater  324
Figure 193: Push-through water heater  324
Figure 194: Low pressure household hot water system (1923)  325
Figure 195: “An Improved Electrical Water Heater” (1923) NZ Patent 51131  327
Figure 196: “Domestic Boiler System” (1926) US Patent 1,612,270  327
Figure 197: 1888 Lighting Fuel Cost Comparison  329
Figure 198: 1930s ‘Mercer’ Gas Storage Water Heater  331
Figure 199: 1930s ‘Champion’ Gas Cooker, Water heater & rubbish destructor59  331
Figure 200: Standing losses as function of tap temperatures  338
Figure 201: Average daily hot water energy use  340
Figure 202: Leaking cylinder - only turns off during ripple control  342
Figure 203: Cylinder that recharges occasionally  344
Figure 204: Cylinder that rarely turns off  344
Figure 205: Night-rate hot water cylinder  345
Figure 206: Example of a vacancy period  346
Figure 207: Example of a vacancy period for a ‘Night rate’ hot water system  346
Figure 208: Solid fuel burner output vs rate of change of cylinder temperature  347
Figure 209: Solid fuel burner output vs rate of change of cylinder temperature  348
Figure 210: Combined electric and wet-back water heating energy  349

[Tables]

Table 1: Location, count and year monitored for HEEP houses  2
Table 2: Fuel use – top and bottom 20%  11
Table 3: Energy end-use by fuel for houses with that end-use  13
Table 4: Total annual energy consumption – all fuels  14
Table 5: Total annual energy consumption per person – all fuels  14
Table 6: Total annual energy consumption – electricity only  14
Table 7: Total annual energy consumption per person – electricity only  15
Table 8: Appliance groups  18
Table 9: Average appliance electricity consumption per household  19
Table 10: Average electricity consumption per appliance  19
Table 11: Average appliance category proportion of electricity  20
Table 12: Lighting power by region  21
Table 13: Participation rate  25
Table 14: Participation rate of households asked to participate in the HEEP study  26
Table 15: What did HEEP record and measure?  28
Table 16: Appliance database  29
Table 17: HEEP people  30
Table 18: Estimated distance travelled by HEEP download staff  30
Table 19: Monitoring equipment  31
Table 20: Logger electrical energy measurement units  34
Table 21: Summary of missing data by circuit  37
Table 22: Summary of missing data by House  37
Table 23: Missing data by year of monitoring  37
Table 24: Missing data - Regional Council  37
Table 25: Missing data - SAMs versus circuit monitoring  38
Table 26: Missing data - Tinytag versus BRANZ temperature loggers  38
Table 27: Missing data – TML  38
Table 28: Circuits missing  38
Table 29: The most common reasons for missing data  39
Table 30: HEERA 16 regions – Regional Councils and Territorial Authorities  59
Table 31: Basic dwelling types for categorising New Zealand dwelling stock  66
Table 32: Extended dwelling types used for categorising the NZ dwelling stock  67
Table 33: HEEP and 1971 descriptive temperatures by region  70
Table 34: Mean temperatures: living room, bedroom and ambient  73
Table 35: Reported evening, all day and no heating by region  75
Table 36: Percentage of houses on various heating schedules  76
Table 37: Pre- and post-1978 heating schedule  76
Table 38: Reported heating season  77
Table 39: Average heating season by region (from north to south)  78
Table 40: Heating start and end month by region  81
Table 41: External temperatures over heating season  82
Table 42: Winter living room evening temperatures by heater type  84
Table 43: Living room winter evening temperature distribution  84
Table 44: Winter temperatures by insulation level  86
Table 45: Regional living room temperatures by insulation requirements  87
Table 46: Temperature difference between upper & lower logger by regional council  89
Table 47: Most used heater type and temperature difference  89
Table 48: Mean temperature during time periods  93
Table 49: Temperatures during afternoon solar gains and evening heating  107
Table 50: Average monthly living room evening temperatures in Hamilton houses (°C)  109
Table 51: Bedroom overnight temperatures in Hamilton houses (°C)  109
Table 52: Income, living room temperature and energy use descriptive statistics  117
Table 53: Correlations equivalised income and energy use variables  117
Table 54: Paired model summaries equivalised income and energy variables  118
Table 55: Household size, living room temperatures and energy use statistics  118
Table 56: Correlations equivalised income and energy use variables  119
Table 57: Paired model summaries household size, occupancy and energy variables  119
Table 58: Frequency table of the life stage variable  121
Table 59: Correlations life stage and energy use variables  121
Table 60: Paired model summaries for life stage and energy variables  121
Table 61: Multiple regression analysis for social dynamics variables and energy use  122
Table 62: HEEP equivalised income quintiles  124
Table 63: Equivalised income by at-risk mean temperatures  124
Table 64: Socio-demographic variables and winter evening living room at-risk (<16ºC) mean temperature  125
Table 65: HES average weekly expenditure by income group of household  125
Table 66: Equivalised income quintiles by winter energy expenditure – HEEP households 126
Table 67: Number of bedrooms for Māori & all HEEP households  129
Table 68: Age of house for Māori & all HEEP households  129
Table 69: Roofing insulation status of house for Māori & all HEEP households  130
Table 70: Winter evening living room temperatures for all & Māori HEEP households  131
Table 71: Winter evening living room temp by fuel for all & Māori HEEP households  131
Table 72: Main heating fuel – 1961 to 1971 Censuses & HEEP  134
Table 73: Heating fuels – 1971/72 Electricity Survey, Censuses & HEEP  134
Table 74: Availability of solid fuel appliances in HEEP households  134
Table 75: Solid fuel appliance types in HEEP households (observed data)  135
Table 76: Availability of solid fuel appliances by location  135
Table 77: Availability of solid fuel appliances by climate zone  135
Table 78: Availability of solid fuel appliances by urban/rural area  136
Table 79: Availability of solid fuel appliances by age of house  136
Table 80: Availability of solid fuel appliances by size of house  136
Table 81: Availability of solid fuel appliances by life stage  136
Table 82: Solid fuel appliance type by use in HEEP households (observed data)  137
Table 83: Use of solid fuel appliances by mix of heating fuels for HEEP households with a solid fuel appliance  137
Table 84: House areas heated by solid fuel appliances for HEEP households using a solid fuel appliance (self-reported data)  138
Table 85: Winter evening living room temperatures by heating fuel type for most used heating appliances  138
Table 86: Winter evening living room temperatures by available solid fuel appliance type for households using solid fuel  138
Table 87: Gas Hot Water Heating, Location and Income Characteristics  142
Table 88: Gas Hot Water Heating, Household Size, Composition, Tenure and Life Stage Characteristics  143
Table 89: Hot water cylinder characteristics by type of hot water heating  144
Table 90: Annualised Gross Energy Use and Annualised Gross Energy Use for Hot Water144
Table 91: Average Summer and Winter Fuel Bills for all energy use  145
Table 92: Key Water Use Patterns  146
Table 93: Number of Showers by Household Size by Type of Hot Water Heating  146
Table 94: Bedrooms and Rooms in Private Occupied Dwellings – 2006 Census  148
Table 95: The Size of HEEP Dwellings  149
Table 96: Estimated Typical Monthly Winter Energy Costs by the Size of HEEP Dwellings 150
Table 97: Estimated Typical Monthly Winter Energy Costs by Dwelling and Household Size150
Table 98: Total Energy Annual Use by the Size of HEEP Dwellings  150
Table 99: Total Annual Energy Consumption by HEEP Dwelling and Household Size  152
Table 100: Calibration slopes  156
Table 101: Assumed efficiencies of solid fuel burners  158
Table 102: Annual gross energy input by appliance type  160
Table 103: Variation of gross annual solid fuel energy consumption by location  160
Table 104: HES Household Heating Appliances  162
Table 105: Ownership of LPG heaters in the HEEP sample  163
Table 106: Gross energy output for each heater setting of the non-thermostatically controlled heaters  164
Table 107: Setting assignment errors for one heater  166
Table 108: Usage of LPG heaters from the processed HEEP LPG sample  170
Table 109: Mean LPG heater duration and energy consumption  170
Table 110: Mean energy consumptions for each setting  172
Table 111: Ownership of LPG heater and dehumidifier  173
Table 112: Heat losses for pre-and post-1978 HEEP houses  176
Table 113: Average winter temperatures by heating type  176
Table 114: Comparison of winter temperatures and Heat Index  177
Table 115: Comparison of space heating energy  177
Table 116: Mainly electrically heated houses space heating energy and temperatures  179
Table 117: Summary of model results  181
Table 118: Comparison of STEM and ALF U-value and thermal mass estimates  187
Table 119: Summary of the appliance ownership models  192
Table 120: Summary of the appliance energy models  192
Table 121 Top five appliances by standby power and energy  199
Table 122 Standby energy per house by appliance group  200
Table 123: Heated towel rail average power use  201
Table 124: New Zealand standby and baseload  202
Table 125: Breakdown of faulty appliances by type  208
Table 126: Breakdown of refrigeration appliances by decade  208
Table 127: Performance of algorithm at threshold of 07  209
Table 128: Performance of algorithm at threshold of 09  210
Table 129: Ownership of refrigeration appliances  216
Table 130: Average fraction of reactive energy from constant load  220
Table 131: Hot water cylinder characteristics by type  222
Table 132 Regional annual hot water energy use by fuel (kWh/house with fuel)  222
Table 133: Building Regulations 1992 Clause G12 – Objective  223
Table 134: Building Regulations 1992 Clause G12 – Performance (hot water)  224
Table 135: NZBC G12/AS1 – Water Temperature & Control (3rd Edition 2006)  224
Table 136: DHW fuels – international comparison  225
Table 137: Average DHW energy use by capacity  228
Table 138: Energy & proportion of main end-uses  230
Table 139: DHW Fuel use – top and bottom 20% of houses  231
Table 140: Hot water energy use by number of occupants  235
Table 141: Electric hot water cylinder standards  236
Table 142: Electric storage cylinder standing losses by size and grade  237
Table 143: Total energy consumption and standing losses by HEEP system type  237
Table 144: Household hot water energy use by system type  238
Table 145: Comparison gas & non-gas water heater households  239
Table 146: Regression model for hot water energy use  239
Table 147: Life stage by water heating fuel  240
Table 148: Linear model application – non-gas and gas water heating  241
Table 149: HEEP hot water systems  241
Table 150: Hot water adequacy by fuel type for randomly selected houses  242
Table 151: Hot water adequacy by system pressure  243
Table 152: Wetback use by region  244
Table 153: Cylinder volume range  245
Table 154: Hot water systems by fuel source and cylinder volume  245
Table 155: System pressure by fuel type  248
Table 156: HEEP random electric and gas cylinder descriptive statistics  250
Table 157: House and cylinder age comparison  252
Table 158: Life expectancies of cylinder types  252
Table 159: Hot water requirements for baths and showers  254
Table 160: Self reported bathing times  257
Table 161: Self reported shower duration by time of day per house  257
Table 162: Shower flow ratings  258
Table 163: HEEP shower flow by water pressure and temperature  259
Table 164: Maximum & minimum water flows  259
Table 165: HEEP Shower warm flow rates by WMCS rating  259
Table 166: Effect on average flows from retrofitting ‘low flow’ shower heads  260
Table 167: Auckland water costs (1 Sept 2006)  260
Table 168: High tap temperatures by system type  261
Table 169: HEEP 135 and 180 litre cylinder statistics  262
Table 170: Count of thermostat setting vs tap hot water temperature  268
Table 171: Tap Temperature and use of tempering valve  269
Table 172: Count of cylinder grade by house decade of construction  272
Table 173: Cylinder wrap cost benefit by cylinder grade  273
Table 174: Some alternative measures for D grade 180 litre retrofit  274
Table 175: Methods to reduce hot water emissions  275
Table 176: Length of Heating season  280
Table 177: ALF3 heating schedules  281
Table 178: Mean heating times on winter evenings  282
Table 179: Average heating temperatures in selected houses  283
Table 180: Wall and roof construction  285
Table 181: Construction R-value with no insulation  285
Table 182: Air leakage rates  287
Table 183: Climate locations  288
Table 184: Weighting of spaces for heating  293
Table 185: Standby power and energy for all measured appliances  310
Table 186: Average annual total energy use per house by fuel  311
Table 187: Average annual hot water energy use per house by fuel  311
Table 188: Average annual space heating energy use per house by fuel  311
Table 189: Average annual energy use per house for selected end-uses  311
Table 190: Christchurch Gas Company - Gas cost £ per 1,000 ft³  330
Table 191: Average gas by end-use: projected 1976 use & HEEP use  332
Table 192: NZ Censuses historical summary 1945-2001 – hot water questions  333
Table 193: NZ Censuses 1945-1996 – text of hot water questions  333
Table 194: North America – shower water use  335
Table 195: Australia – shower water usage  335
Table 196: Perth – shower water use  335
Table 197: Hot water energy comparison  337
Table 198: Hot water systems – comparison of properties  337
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