May 06, 2009Katrineholm Implementation of building envelop energy efficiency measures in existing detached houses Leif Gustavsson & Krushna Mahapatra Dept. of Engineering and Sustainable Development Mid Sweden University

Introduction Residential and service sector uses 1/3 rd of total final energy use in Sweden Considerable scope for improving energy efficiency in the existing buildings –decrease energy use by 30 TWh of heat and 15 TWh of electricity (CEC, 2005) Successful implementation of changes depends on attitudes and perceptions of the relevant actors Actors involved vary over the building stock as houses vary in age, size, management and ownership

Research questions 1.To study homeowners’ perception of building envelop energy efficiency measures in detached houses 2.To study the role of energy utilities and energy advisors in influencing homeowners’ decision to adopt energy efficiency measures 3.To study perceptions and attitudes of the manufacturers, retailers, installers and building companies’ towards energy efficiency 4.To analyze the effects of policy measures related to energy and climate change in the context of energy efficiency 5.To give an overview of the drivers to perform energy efficiency improvements, depending on the ownership and management situation

Source: Energy in Sweden, 2008

Annual primary energy use with installation of heating systems and energy efficiency measures Electricity supply systems: coal-based steam turbines (CST), natural gas-based combined cycle (NGCC), and biomass with integrated combined cycle technology (BIG/CC) Source: Joelsson, A. (2008). Primary Energy Efficiency and CO 2 Mitigation in Residential Buildings, PhD Thesis 58, Mid Sweden University, Sweden,.

Adapted from Hawkins et al., 2007; Mahapatra and Gustavsson, 2008 Stages in homeowners’ adoption of a building envelop energy efficiency measures Influence of government policy instruments, e.g. subsidies Collection of Information Selection of an installation Mass media, interpersonal communications, change agents Perceived advantages - Economic - Ease of installation - Environmental Stage 2 Stage 3 Age, physical condition, aesthetics, and energy performance of existing installation, awareness about better alternative, perceived higher utility bill, demographic factors Stage 1 Need for a new installation

Survey of homeowners 3000 homeowners selected through stratified random sampling Survey through Statistics Sweden during May-July % response rate after two reminders No non-response bias –Geographical location, age of house and respondents’ income –Higher aged (>55 yrs) people are over- represented by about 5%

Actions respondents may take to improve efficiency of household energy use (1) Switch off appliances when not required80% Switch off lights74% Lower thermostat setting50% Adoption of investment oriented measures36%

Actions respondents may...(2) Source: Europeans’ attitudes towards climate change, Eurobarometer 300, 2008 Installed equipments that generate renewable energy Switched to an energy supplier or tariff supplying a greater share of energy from renewables Personal interviews March-June 2008 N=1007, statified random sampling

Homeowners' plan to install an energy efficiency measure

Age of existing installation

Age of installation vs. respondents’ plan to change window or attic insulation

Respondents’ perception of various attributes of existing installations Attic insulation Wall insulation Window Attic insulation Window Wall insulation Facade Physical conditionThermal performance Aesthetics % of respondents

Respondents level of satisfaction with thermal performance of existing installation vs. their plan to change window or attic insulation

Respondents perception of energy cost burden vs. their plan to change window or attic insulation

Respondents household income vs. their plan to change window or attic insulation

Respondents’ level of education vs. their plan to change window or attic insulation (%)

Respondents’ age vs. their plan to change window or attic insulation (%)

Homeowners’ perception of importance of sources of information on energy efficiency measures

Respondents’ awareness of energy advice service Are you aware about existence of energy adviser in your locality? (N=1061)  Yes = 50%  No = 7%  Do not know = 43%

Actual consultation with external actors for household energy reduction N = Number of respondents

Perceived quality of external actors' suggestion N = Number of respondents who contacted the respective source

Respondents’ implementation of energy advisers’ suggestions 57% of those consulted an energy adviser implemented the suggestions (≈8% of total respondents) 43% did not implement the suggestions mainly because –suggestions were not specific (21%) –already implemented (24%) –expensive to be implemented (33%) –other reasons (22%)

Important factors in homeowners’ choice of energy efficiency measures (decreasing order of importance) A higher mean indicates higher importance FactorsNMeanStd. Error Annual saving of energy cost Initial investment cost Functional reliability Maintenance requirement Indoor ambience Environmental benefit Increase market value of house Ease of installation GHG emission reduction Time required to collect information

Awareness about subsidies About 36% of respondents knew about government support for adoption of energy efficiency measures of which About 1/3 rd knew about investment subsidies for windows of which 53% (≈ 6% of total respondents) considered the subsidy important in their adoption decision

Homeowners’ perception of annual energy cost

Homeowners’ perception of GHG emission reduction

Perceived advantages of energy efficiency measures Energy efficiency measurePerceived advantage Improving attic insulationAnnual energy cost saving Low initial investment Low maintenance requirement Ease of installation Environmental benignity Energy efficient windowIncrease in market value of house Better room environment Improving wall insulationLow ranking on all factors

Energy efficiency measure that respondents would recommend to peers and friends

% of respondents reporting the year of installation of existing windows and attic insulation Conclusion: Attic insulation is preferred but more windows are installed Age of installation

Greater observability of windows Attributes Percentage of respondents who “did not know” about the existing building envelop component WindowAttic insulation External wall insulation Age of installation12%18%20% Physical condition 0.4 % 9 %11% Thermal performance 2% 7% 4%

Main findings 70 – 90% do not plan to install a building envelope energy efficiency measure Economic factors guide adoption decision –Environmental factors are given low priority Large proportion of respondents do not know about various attributes of building envelope energy efficiency measure Attic insulation has greater perceived advantages, but windows are more adopted –Investment subsidy, observability Interpersonal source, construction companies, installers, and energy advisors are important sources of information Large percentage of homeowners are unaware about the energy advisers in their area or dissatisfied with their suggestions

Suggestions that may increase adoption of building envelop energy efficiency measures Economic instruments useful Improve awareness among homeowners about economic instruments and economic efficiency of adopting building envelope components Facilitate a more effective interaction between important external actors and homeowners More publicity and competence development of energy advisers

Thank you for your attention!