Model Project 11 / Ireland. Data collection from energy audits for residential buildings. Summary Report

Transcription

1 Collecting Data from Energy Certification to Monitor Performance Indicators for New and Existing buildings Model Project 11 / Ireland Data collection from energy audits for residential buildings Summary Report Energy Action Limited Dublin, Ireland March 2008 with the support of Coordinator: Contract N : EIE/05/097 Institut Wohnen und Umwelt, Darmstadt / Germany Project duration: Jan Dec 2008 The sole responsibility for the content of this publication lies with the authors. It does not necessarily reflect the opinion of the European Communities. The European Commission is not responsible for any use that may be made of the information contained therein

2 Authors: Michael Hanratty Dr. Bill Sheldrick Energy Action Limited 14 Newmarket Dublin

3 Contents 1. Summary Description of the Irish Model Project Objectives and key actors Data collection method Data Evaluation General statistics Thermal envelope and useful energy demand of the buildings Supply systems Delivered energy Comparing DEAP and IHER calculation methods DEAP BER score vs IHER score Space heating delivered energy: DEAP vs IHER Hot water selivered energy: DEAP vs IHER Carbon Dioxide Emissions (kgco 2 /m 2 /year): DEAP vs IHER Conclusions

4 1 Summary Objectives of the DATAMINE Project The starting point of DATAMINE is the fact that the actual state of the European building stock and the on-going retrofit processes are not very well known until now. This information gap can be seen as a great obstacle for taking well-tailored measures to reduce the buildings energy consumption. The idea of DATAMINE is to use Energy Performance (EP) Certificates as a data source for monitoring. Given the great variety of buildings as well as certificate types in Europe and the very different status of national EPBD implementation a general monitoring system can only be implemented in the long run. Thus the objective of DATAMINE is to make basic experiences in data collection and analysis on a practical level and to draw conclusions for establishing harmonised monitoring systems. For this purpose Model Projects are carried out in 12 EU member states. In each Model Project data collection and monitoring by use of EP Certificates is tested on a small scale. Each Model Project has an individual design, addressing different building utilisations and certification types as well as data collection methods and monitoring targets depending on the focus of the involved key actors. Accordingly, each Model Project considers different national certification or data collection activities. The experiences and evaluations which were made in the Irish Model Project are described in this report. Similar reports exist for the other DATAMINE Model Projects showing the individual concepts and results. A survey of the most relevant results from all Model Projects is given in the DATAMINE Synthesis Report SR2 Data Collection from Energy Certificates Experiences and Analysis. Status of introduction of Energy Performance Certificates in Ireland The requirement for Energy Performance Certificates for new dwellings based on the primary energy demand for heating and hot water came into effect on 1 st January This applied only to new dwellings for which planning permission was applied for or a planning notice was published on or after 1st January 2007, and where substantial work is completed by 30 June The requirement for Energy Performance Certificates for new non-residential buildings will come into effect on 1 st July This will not apply to buildings, other than dwellings, for which planning permission is applied for or a planning notice is published on or before 30 th June 2008 and where substantial work is completed by 30 th June 2010, except when such building is offered for a second or subsequent sale or letting. For existing buildings of any class in existence at 1 January 2009, an Energy Performance Certificate will be required when the building is offered for sale or letting

5 Fig. 1: Status of Energy Performance Certificate introduction in Ireland Dates for Implementation of EPBD Residential dwellings* (asset only) new dwellings** 1st January 2007 existing dwellings when sold or rented 1st January 2009 Non-residential Buildings*** new buildings**** 1st July 2008 existing buildings 1st January 2009 *) apartments are treated on an individual basis **) where planning application made on or after ***) operational for public buildings, asset-based for others ****) where planning application made on or after The DATAMINE Model Project in Ireland Objectives The objectives of the Datamine model project in Ireland are: to demonstrate how Datamine can record key building energy rating (BER) data for a large population of BER certificates to highlight practical issues arising in populating the Datamine database (or similar databases) with BER certificate data to show the range of analytical facilities that Datamine can provide for large populations of BER certificates to monitor the improvement in energy performance (energy rating score, annual heating costs and CO 2 output) pre and post installation of energy saving measures to inform Sustainable Energy Ireland (responsible for EPBD implementation in Ireland) and relevant Government Departments of the benefits and learnings arising from the Datamine project to advise Dublin City Council and other Local Authorities with large stocks of housing of the merits of the Datamine database and analytical tool for management of BER certificate data, housing stock analysis and strategic planning input. Key Actors The key actors are Dublin City Council, other Local Authorities with large stocks of houses, Sustainable Energy Ireland, The Department of the Environment, Heritage and Local Government, the Department of Communications and Energy, and, energy surveyors/ energy consultants. The Data Collection Method - 5 -

6 Energy Action has conducted many major studies on existing Irish housing stock over the last 10 years and so has a large database of private sector produced energy rating certificates. As work on the Irish model project preceded EPBD implementation for new dwellings in 2007 and that for existing dwellings in 2009, the data being used for the Datamine project was initially taken from pre-2007 energy rating certificates prepared using the Irish Home Energy Rating (IHER) method. The Irish Home Energy Rating method was developed under a technology transfer project in 1999 funded under an EU SAVE Programme by a partnership involving National Energy Services, (UK), Energy Action Limited, Dublin, the Energy Research Group, University College Dublin and Alembic Research (Scotland). The IHER software is based on a derivation of the UK National Home Energy Rating (NHER) method adapted to Irish conditions. As NHER is SAP-based, the IHER method is also UK SAP-based. In implementing the EPBD in Ireland, Sustainable Energy Ireland decided to adapt the latest UK SAP method to Irish conditions leading to the launch of the Dwelling Energy Assessment Procedure (DEAP) method in late Some different adaptations were made when creating DEAP to those made when the IHER method was originally developed. The launch of the DEAP software in Ireland in April 2007 has allowed the original data used in the IHER energy ratings to be entered into the DEAP software program. While the DEAP method for existing dwellings will only be available from July 2008 approx., it has been possible to produce DEAP BER ratings for existing dwellings by combining IHER default U-value data for building fabric with the DEAP software for new dwellings. For the purposes of the Datamine project, data from 126 dwellings originally audited using the IHER method has been entered into the DEAP software to calculate the various energy performance parameters using the DEAP software. All 126 BER rating data produced by the DEAP software has been entered into the Datamine database. The DEAP method provides a BER label ranging from A to G based on primary energy demand, i.e. kwk/m 2 /year. DEAP is based on a single climate for all of the Republic of Ireland and does not take account of height above sea level or wind speed data. The IHER method scores a dwelling on a scales of 1 to 10, where 10 is the most energy efficient and is based on energy costs ( )/m 2 /year. IHER take account of geographical location, height above sea level and wind speed data. Main results of the data evaluation 126 datasets have been analysed to date. All datasets are for existing dwellings including houses and apartments. In Ireland, each individual apartment is treated as a separate dwelling. The common areas in apartment buildings will be evaluated as non-residential buildings under the EPBD. Fig. 2: General Statistics of the analysed datasets Number of collected datasets 126 Rating Methods IHER, DEAP residential dwellings 126 asset ratings 126 Considered energy uses space heating 126 hot water 126 cooling/ air conditioning 0 lighting 0 others 0-6 -

7 All 126 dwellings have been analysed using both the original IHER method and the new DEAP method introduced as part of EPBD implementation in Ireland in January

8 Conclusions Collection Method To date, BER certificate data has been analysed for 126 dwellings using both the IHER method and the new DEAP method. The DEAP BER data was entered manually into the Datamine database as the DEAP xml file does not contain much of the essential energy performance data that is required. Currently, the xml data stream within the DEAP software only contains the input data. It does not contain any of the calculated energy outputs that would be essential for data analysis in Datamine or elsewhere. SEI has been notified of this and more formal discussions will take place in early 2008 to see if this shortcoming can be addressed. It was hoped that an export tool can have been developed to transfer DEAP BER data into the Datamine database or other national, regional or corporate databases as required. Energy Performance of the Analysed Buildings The initial analysis of the datasets has focussed on comparing for the first time the correlation between the IHER method and the DEAP method for the available dataset of 126 dwellings. The results shown in Section 3 show that there is reasonably close correlation apart from water heating energy values. Given our long experience with IHER over the last 10 years and our short experience of the new DEAP method, it was important to understand the relation between the calculations behind both methods before undertaking more comprehensive data analysis of 126 datasets under one or other method. A wide range of charts are produced in Section 3 showing the power of the Datamine database and its analysis tool for examining the thermal envelope (ranges of U-values, useful energy demand), supply system and energy performance. The capabilities of the database would be even better demonstrated with a much bigger and active dataset. Perspectives for Future Monitoring Activities As indicated above, the DEAP xml file does not contain any of the calculated energy outputs that would be essential for data analysis in Datamine or elsewhere. This needs to be addressed so that the National Administration body, Governments Departments and organisations with small to large stocks of housing can avail of data collection and analysis tools. The next phase of the Irish project will involve expanding the number of datasets to at least 150 dwellings now that the comparative work between IHER and DEAP has been completed. The Datamine database and analysis will be deployed on an ongoing basis on other energy audit projects

9 2 Description of the Irish Model Project 2.1 Objectives and key actors The objectives of the Datamine model project in Ireland are: to demonstrate how Datamine can record key building energy rating (BER) data for a large population of BER certificates to highlight practical issues arising in populating the Datamine database (or similar databases) with BER certificate data to show the range of analytical facilities that Datamine can provide for large populations of BER certificates to monitor the improvement in energy performance (energy rating score, annual heating costs and CO 2 output) pre and post installation of energy saving measures to inform Sustainable Energy Ireland (responsible for EPBD implementation in Ireland) and relevant Government Departments of the benefits and learnings arising from the Datamine project to advise Dublin City Council and other Local Authorities with large stocks of housing of the merits of the Datamine database and analytical tool for management of BER certificate data, housing stock analysis and strategic planning input. Sustainable Energy Ireland (SEI) is responsible for EPBD implementation and administration in Ireland. In the medium term, SEI plans to enter into a contract with a private provider for National Administration of the BER scheme. However, for the present moment, SEI will manage all administration of BER certification in Ireland. It should be noted that prior to the EPBD, there was limited (in scale) building energy rating activity in Ireland represented primarily by the IHER scheme unlike England for example. Thus, those charged with EPBD implementation in Ireland were presented with an almost clean slate when designed the EPBD methods and administration systems. In implementing the EPBD in Ireland, Sustainable Energy Ireland decided to adapt the latest UK SAP method to Irish conditions leading to the launch of the DEAP methodology in late Some different adaptations were made when creating DEAP to those made when the IHER method was originally developed. The Dwelling Energy Assessment Procedure (DEAP) method for New Dwellings was published in mid When the EPBD (Energy Performance of Buildings Directive) was introduced for new dwellings on 1 January 2007, the legal requirements for BER certificates for all new dwellings (where planning permission was appled for on or after 1 January 2007) came into force using the DEAP method. As Energy Action has considerable experience of working with significant numbers of BER certificates and producing analytical reports, it is fully aware of the benefits of collecting key BER data for the purposes of reporting, analysing and using the results for strategic decision making. With the advent of EPBD in Ireland, it is predicted that between 150,000 and 180,000 BER certificates will be issues for new and existing dwellings in What may not be clear to many at this stage is the need to make all of this important data available in a form that can be used for both data collection and analysis. Firstly, SEI or the body it may appoint as National Administrator of the BER scheme will have data collection and reporting requirements. Also, local authorities such as city councils, town council, county councils, housing associations and property management - 9 -

10 companies will acquire hundreds and thousands of BER certificates for their housing stocks. In many cases, they may also be conducting refurbishment programmes that will result in improved energy ratings and lower CO 2 emissions for their dwellings. Very soon, many of those organisations will require tools that will enable them to collect, record and ultimately make best use of all their BER certificate data. The main objective of the Irish project is to demonstrate what tools will be required to collect/export data from the DEAP software and to prepare detailed analysis of the BER certificate data on a large scale. The detailed analysis will vary considerably between newer dwellings and existing older buildings. For example, for new dwellings, the number of A1, A2, A3, B1, B2 etc energy ratings can be shown on an annual or regional basis as can U values of floors, roofs, walls and windows as can efficiencies of heating systems. For existing dwellings, U values, heating systems efficiencies, fuel types etc can be reported. More importantly, however, would be the facility to report on the reductions in CO 2 emissions and higher energy ratings arising from refurbishment projects. Many local authorities and housing associations are actively upgrading/ refurbishing their housing stocks with improved insulation, more efficient heating systems and improved glazing. However, very few of these organisations are conducting energy audits on these dwellings before and after implementation of these measures. Thus, they are not gaining the credit they deserve for the associated reductions in CO 2 emissions. The focus of this report will be to report on the DEAP BER data analysis produced by the Datamine analysis tool for the 126 dwellings entered and to demonstrate the comparisons between BER calculated values using both IHER method and DEAP method

11 2.2 Data collection method Energy Action has conducted many major studies on existing Irish housing stock over the last 10 years using the Irish Home Energy Rating (IHER) method. One such study was the Ballyfermot Residential Energy and Fuel Poverty report in Ballyfermot is a district in Dublin city containing over 6,500 dwellings. All of these dwelling types were audited and the impact of a range of energy improvement measures were assessed in terms of reduced fuel costs to householders, reduced CO 2 emissions and improved energy ratings. Work on the Irish model project for Datamine preceded EPBD implementation in Ireland. In implementing the EPBD in Ireland, Sustainable Energy Ireland (SEI) decided to adapt the latest UK SAP method to Irish conditions leading to the launch of the Dwelling Energy Assessment Procedure (DEAP) method for New Dwellings in late The first version of the DEAP software was quickly withdrawn to address some significant initial bugs. The DEAP software was subsequently rereleased in April While it still has some smaller bugs, it is now operational. While different adaptations were made when creating DEAP to those made when the IHER method was originally developed, the IHER and DEAP methodologies are actually quite similar. As few existing building energy ratings have been conducted in Ireland before 2007 apart from those done using the IHER method, and since DEAP had not yet been introduced, it was decided that energy audits conducted using the IHER method would be used for the Irish Datamine project. All building energy rating data being used for the Datamine project was taken from pre 2007 energy rating certificates prepared using the Irish Home Energy Rating method All IHER energy audits on file are for existing dwellings. However, when the IHER Site Assessor method (for existing dwellings) was developed in 1998, a table of default U values for building elements of different ages was developed. Thus, it has been possible to re-enter all of the IHER audit data into the DEAP software using the default U values available from the IHER method. As there is a considerable quantity of IHER audit data available, it was decided that the first step in the Irish project would be to compare BER calculated values using both IHER method and DEAP method. All data collected so far for the IHER energy audits has been inputted manually into the Datamine database. When the DEAP software became available, it was hoped that the xml data file produced by the DEAP software would contain key calculated energy data such as water heating requirement, storage losses, distribution losses, net space heat demand, distribution losses and gains, delivered heat requirement, primary energy requirements etc.. However, the DEAP xml file only contains the string of input data thus allowing the inputs for the DEAP calculation for one dwelling to be transferred in order to replicate the building energy rating for that dwelling. The xml file presently does not contain any of the output data as described above which is the much of the essential data needed for the Datamine database. So, the data from the 126 energy audits that were re-created in the DEAP software were also physically read by our researchers and manually inputted into the Datamine database. The shortcomings of the DEAP software with respect to data export have been advised to SEI and they have agreed to explore how to overcome this issue in early

12 It is hoped that the xml file can be re-configured to include all of the critical calculated energy values and a suitable tool can be developed to export a defined list of fields to the Datamine database or similar databases

13 3 Data Evaluation 3.1 General Statistics The 126 building in the Irish Datamine dataset are single family dwellings. The most common building size is between 70m 2 and 90m 2. Fig 3 Frequency of Building Size Classes Conditioned floor area [m²] Number of datasets <=50 5 >50 and <=70 20 >70 and <=90 72 >90 and <= >150 5 total 126 A_C_ref* The 126 dwellings are of different ages as shown in figure 4. The biggest number was built between 1960 and Before 1900 and between 1900 and 1920, the number of dwellings is small, 3 and 4 respectively. Fig 4 Frequency of Building Construction Cycle Construction cycle <=1900 >1900 and <=1920 >1920 and <=1940 >1940 and <=1960 >1960 and <=1980 >1980 and <=2000 > Number of datasets year_building* total

14 3.2 Thermal Envelope and Useful Energy Demand of the Buildings The thermal envelope of the 126 dwellings entered into the Datamine database were analysed using the data analysis tool developed by IWU. The transmission or fabric losses (W/m 2 K) of the dwellings are indicated according to property age in figure 5 below. The dwellings beyond 1980 have a markedly bettter performance. Building regulations were first intoduced in Ireland in 1991 and have been revised upwards in 1997, 2002 and A further revision is proposed for Fig 5: Transmission (Fabric) Losses per m 2 envelope (similar to mean U-Value of the envelope) Construction cycle Temperature and envelope related transmission losses [W/(m²K)] <= >1900 and <=1920 >1920 and <=1940 >1940 and <= >1960 and <= >1980 and <= > ALL 1.45 year_building* H_T_per_sqm_envelope* The mean U-value of walls based on dwelling age is indicated in figure 6 below. The mean U-value decreased significantly after Fig 6: Mean U-value of Walls, based on building construction cycle Construction cycle Mean U-value walls [W(m²K] <= >1900 and <= >1920 and <= >1940 and <=1960 >1960 and <= >1980 and <=2000 > year building* U_wall ALL

15 The mean U-value of windows based on dwelling age is indicated in figure 7 below. Many older dwellings in Ireland have had their windows replaced once the original windows fall into disrepair. As a result, the drop in the mean window U-values is less pronounced. The lowest mean U-values are for the post 2000 dwellings. Fig 7: Mean U-value of Windows, based on building construction cycle Construction cycle Mean U-value windows [W(m²K] <= >1900 and <= >1920 and <=1940 >1940 and <=1960 >1960 and <=1980 >1980 and <= > year building* U_window ALL 3.93 The mean U value of roofs based on dwelling age is shown in figure 8. The lowest mean U value is for the period. The > 2000 dwellings have a higher mean U-value than the dataset. This arises because the >2000 dwellings included in this dataset were audited because of poor performance. That audit process showed that the dwellings were not built in full compliance with the prevailing building regulations. The post 2000 dwellings would be seen to perform best if a bigger dataset was used. Fig 8: Mean U-value of Roofs, based on building construction cycle Construction cycle Mean U-value roofs and top ceilings [W(m²K] <= >1900 and <= >1920 and <= >1940 and <= >1960 and <= >1980 and <= > year building* U_roof ALL

16 The mean U-value of floors is shown in figure 9. The most consistent trend is from 1940 to 1980 which shows a gradual reduction in mean floor U-values. Fig 9: Mean U-value of floors, based on building construction cycle Construction cycle Mean U-value basement [W(m²K] <= >1900 and <= >1920 and <= >1940 and <= >1960 and <= >1980 and <= > year building* U_basement ALL 0.86 The range of useful energy demand for space heating (Q_H_gross) across the dataset of dwellings is shown in figure 10 below. 86 dwellings had a mean useful energy demand between 50 and 150 kwh/m 2 /annum. In the DEAP method, Q_H_gross was deemed to be the Net Space Heat Demand value, which is the space heating required for the October-May heating period. Fig 10: Frequency of the useful energy demand for space heating Useful energy demand space heating [kwh/(m²a)] Number of buildings <=50 >50 and <=100 >100 and <=150 >150 and <=200 >200 and <=250 >250 and <=300 >300 ALL Q_H_per_sqm*

17 The mean values for net space heat demand based on building age are shown in figure 11 below. As would be expected, the value decreases with newer dwellings due to improved thermal performance. Fig 11: Mean values for useful calculated energy demand for space heating per building age Construction cycle <=1900 >1900 and <=1920 >1920 and <=1940 >1940 and <=1960 >1960 and <=1980 >1980 and <=2000 >2000 ALL Heat demand for space heating per sqm reference area [kwh/(m²a)] year_building* Q_H_per_sqm* The mean energy demand for space heating based on building size is shown in figure 12 below. The energy demand value is lowest for the largest buildings. Fig 12: Mean values for useful calculated energy demand for space heating per building size Conditioned floor area [m²] <=50 Heat demand for space heating per sqm reference area [kwh/(m²a)] >50 and <= >70 and <= >90 and <= > total 116 A_C_ref* Q_H_per_sqm*

18 3.3 Supply Systems Natural gas is the most common form of heat generation occurring in 72 of the 126 dwellings as shown in figure 13. Coal is second most common ahead of oil. Coal would generally be less prominent in a bigger national dataset. It has a high proportion within this dataset as many of the dwellings were audited in their original state as part of refurbishment programmes. Fig 13: Frequency of energy carriers used by the main heat generator Energy carrier type Number of buildings natural gas liquid gas oil coal biomass electricity district heating other ALL class_ecarrier* The frequency of hot water systems is shown in figure 14. Again natural gas is most common. Coal should appear in this chart as a coal-fired backboiler provides both space and water heating. (Further work is required to discover why coal did not appear in the chart). Fig 14: Frequency of hot water system types & respective energy carriers Type of hot water system Number of buildings combined with heating separate natural gas liquid gas oil coal biomass electricity district heating other class_hotwater_system* class_1st_ecarrier_w*

19 The frequency and age of heat generator types is illustrated in figure 15 below. The chart will be especially useful for showing boiler types and ages for larger datasets. Fig 15: Frequency of heat generator construction cycles Type of heat generator Number of buildings boiler, type unknown <=1975 non-cond. boiler, details unknown const. temp. non-cond. boiler low temp. non-cond. boiler condensing boiler stove combined heat and power electr. direct (resist.) heat pump, type unknown heat pump, outside air heat pump, soil heat pump, exhaust air >1975 and <=1980 >1980 and <=1985 >1985 and <=1990 >1990 and <=1995 >1995 and <=2000 >2000 and <=2005 heat pump, ground water type_heatgen_1* year_heatgen* heat pump, other >2005 The frequency of hot water storage water losses is shown in figure 16. It may be more insightful to also view water storage losses by building construction cycle. Fig 16: Frequency of hot water system storage losses (per m2 reference area) Hot water storage losses [kwh/(m²a)] =0 >0 and <=5 >5 and <=10 >10 and <=20 >20 and <=30 >30 and <=50 >50 and <=70 >70 and <=100 >100 and <=150 Q_W_s_per_sqm* > Number of buildings (total 126)

20 At the time of writing this report, it was not possible to produce the chart showing hot water storage losses. The Q-W_d value would not transfer from the database file into the analysis tool. This problem should be overcome shortly

21 3.4 Delivered Energy The frequency of primary energy demand is shown in figure 17 below. The primary energy demand is that for the space heating, water heating and lighting referred back to the primary energy source. In the DEAP method, delivered electrical energy (at the dwelling) is multiplied by a factor of 2.7 to reflect its fossil fuel carbon content at source. The electricity multiplier factors in generation efficiencies and electrical transmission and distribution losses. For natural gas and oil the multiplier is 1.1 reflecting pumping/ refining/ transport factors. The buildings with the biggest primary energy demand have an electrical heating content. (Coal does not appear in this chart similar issue to earlier). Fig 17: Frequency of Primary Energy Demand Prim. energy demand Number of buildings per m² ref. area [kwh/(m²a)] <=100 >100 and <=200 >200 and <=300 >300 and <=400 >400 and <=500 >500 and <=600 >600 natural gas liquid gas oil coal biomass electricity district heating other Q_P_per_sqm* class_ecarrier_1* The frequency of calculated energy demand is shown in figure 18. Those dwellings that included electricity had the highest values. (The coal values were not included here). Fig 18: Frequency of calculated energy demand (summarised for all energy carriers per m 2 reference area) Calculated energy demand for Number of buildings heating and hot water [kwh/(m²a)] <=50 >50 and <=100 >100 and <=150 >150 and <=200 >200 and <=250 >250 and <=300 >300 and <=350 >350 and <=400 >400 Q_del_sum_c_per_sqm_without_aux* class_ecarrier_1* Main energy carrier natural gas liquid gas oil coal biomass electricity district heating other

22 3.5 Comparing DEAP and IHER Calculation Methods BER energy value Vs IHER Score As the Datamine project co-incided with the changeover from the IHER method to the DEAP method, further analysis was done to compare both methods. The IHER method and the DEAP method are both based on the UK SAP calculation method. The DEAP method provides a BER label ranging from A to G where A is the most efficient. It is based on primary energy demand and indicates an energy values in kwh/m 2 /year and a carbon dioxide emissions rating in kgco 2 /m 2 /year. DEAP is based on a single climate for all of the Republic of Ireland and does not take account of height above sea level or wind speed data. The IHER method scores a dwelling on a scale of 1 to 10, where 1 is the least energy efficient and 10 is the most energy efficient. The IHER rating is based on energy costs ( )/m 2 /year. IHER takes account of geographical location on a county by county basis, height above sea level and wind speed data. A smooth correlation is shown between the IHER score and the DEAP BER energy value in figure 19 below. Fig. 19: BER energy value (kg/m 2 /year) Vs IHER score BER energy value vs IHER score IHER scale BER energy value (kwh/m2/year)

23 3.6 DEAP BER Score vs IHER Score A reasonably strong correlation is demonstrated in figure 20 between the DEAP BER scale (based on kwh/m 2 /year) and the IHER score (based on energy costs ( )/m 2 /year) for the same dwellings, which is what was generally expected. Fig. 20: BER rating (A to G) Vs IHER score IHER scale BER vs IHER score BER scale

24 3.7 Space Heating Delivered Energy: DEAP Vs IHER The comparison of delivered energy for space heating between DEAP and IHER is shown in figure 21. There is a reasonable correlation for this calculation between the DEAP and the IHER method. Fig. 21: Space heating delivered energy : DEAP Vs IHER Space Heating Delivered Energy: DEAP vs IHER calculation IHER calculated DEAP calculated delivered space heating demand (kwh/year)

25 3.8 Hot Water Delivered Energy: DEAP Vs IHER There is no correlation between the delivered energy for hot water between the delivered hot water for DEAP and IHER, as demonstrated in figure 22 below. There has been an upward revision of hot water requirements in more recent versions of SAP (DEAP is based on the most recent version) which may explain this finding. Fig. 22: Hot water delivered energy : DEAP Vs IHER Hot Water Delivered Energy: DEAP vs IHER calculation IHER calculated DEAP calculated delivered hot water demand (kwh/year)

26 3.9 Carbon Dioxide Emissions (kgco 2 /m 2 /year): DEAP Vs IHER There is a reasonably strong correlation between the carbon dioxide emissions as calculated for DEAP and IHER. This graph (figure 23) is similar to that for space heating delivered energy. Fig. 23: Hot water delivered energy : DEAP Vs IHER IHER calculated Carbon Dioxide Emissions KgCO2/m2/year): DEAP vs IHER calculation DEAP calculated CO2 emissions (CDER) (kgco2/m2/year)

27 4 Conclusions This analysis has assisted in providing a deeper understanding of the range of calculated values in the DEAP BER audits. It demonstrates that all key BER data can be captured and used for very comprehensive analytical purposes. When applied to greater populations of buildings, database/analytical tools such as Datamine will provide a valuable resources to national BER programmes, managers of housing stock and energy assessors/consultants providing services to housing associations and local authorities. This initial analysis has also included a comparison of the newer DEAP and older IHER methods. It is clear that there is a strong similarity in the calculation methods in most cases. The exception is water heating delivered energy