Abstract Investments in energy efficiency are widely recognized as a cornerstone of sustainable energy strategies and climate change mitigation efforts, offering not only environmental benefits but also delivering substantial socio-economic gains. However, conventional evaluation frameworks tend to focus predominantly on operational energy savings, often neglecting broader lifecycle effects associated with manufacturing, packaging, installation, and maintenance phases. These include wealth and job creation, as well as embodied energy and emissions. This study introduces a comprehensive approach that integrates the Hybrid Input–Output Lifecycle Assessment methodology into Portugal’s 2021 Energy Consumption Efficiency Promotion Plan framework. By incorporating Gross Value Added, Impact on the Public Budget and embodied energy and greenhouse gases emissions this approach extends conventional Primary Energy Savings, Net Present Value and Benefit–Cost Ratio calculations typically employed in cost-effectiveness analysis, allowing a comparative evaluation of the results. The findings reveal significant variations in evaluation outcomes, with Net Present Value rising by over 4,000%, Benefit–Cost Ratio increasing by more than 34%, and two measures changing position in the funding priority ranking. These results highlight the transformative potential of the proposed methodology for guiding energy policy, supporting a more equitable and effective allocation of public funds. By incorporating broader lifecycle impacts and societal benefits, the approach also enhances the robustness of energy efficiency evaluations, paving the way for improved decision-making in national and international energy programs.

Recent studies have used algorithm tailoring on digital platforms to provide household energy-saving advice. Such ‘recommender systems’ have successfully used the psychometric Rasch model as an advice algorithm, matching energy-saving measures in terms of their difficulty to consumers’ ability levels. While these previous studies indicated positive user experiences, tailored advice did not lead to higher savings overall; not even when also using persuasive nudges, such as displaying social norm percentages in the system. One possible reason for these results was that the system was used exploratively, allowing users to pick energy measures as they liked without tapping into goal setting or value-based motivational frames (e.g., signposts). In this study, 202 participants used and evaluated our ‘Saving Aid’ Rasch recommender system, choosing energy-saving measures they would like to perform at home. Through a 3 × 2-between subject design, we examined whether guided goal setting and signposts (kWh/Euro/CO2) affected user experience and energy savings. Following the signpost literature, we examined the moderation of these effects by user values, such as environmental concern (New Environmental Paradigm (NEP) score). A structural equation model analysis revealed that goal setting did not affect outcome variables, while signpost framing had varying effects, although these were not in line with prior expectations. Still, the overall system remains promising, with users achieving a 316 kWh yearly savings with the chosen recommendations.

Building codes currently regulate energy efficiency in newly constructed buildings in Sweden. Alongside energy declarations, performance-based regulation specifying specific energy use requirements was introduced in Sweden in 2006. The requirements have been subsequently tightened to enhance energy performance. This study estimates the impact of these requirements on energy savings in Swedish multi-apartment buildings, relying on specific energy use data from energy performance certificates (EPCs). An estimated time trend indicates greater energy efficiency at a rate of 1.57% per year for buildings with district heating and 1.09% per year for electrically heated buildings. After accounting for this trend, the results indicate that the implementation of performance-based regulation is associated with a 14.2% increase in energy efficiency for buildings with district heating and a 9.7% increase for those with electric heating. Moreover, the first tightened building codes generates an additional 2% increases in energy efficiency for district-heated buildings and an approximately 7.4% improvement for electrically heated buildings. However, there is no evidence to suggest that the second tightening of building codes have strong effects on further increasing energy efficiency. Furthermore, the effect of building codes is more substantial for buildings where actual energy use exceeds the mandated levels and modest for buildings with better energy performance. Alternatively, when studying the time trend of energy efficiency, I find a structural break with a significantly greater increase in efficiency over time during the period of regulation compared to before. In addition, findings in this study indicate evidence of the energy performance gap, where the estimated energy use from engineering models is substantially lower than the measured energy use for comparable construction.