Improving Energy Efficiency in BuildingsTABLE OF CONTENTSEXECUTIVE SUMMARY 1IMPROVING ENERGY EFFICIENCY IN BUILDINGS 3 The Opportunities 4 Barriers and Challenges 5 Solutions 6PART I: ENERGY EFFICIENCY IN NEW BUILDINGS 9Mandatory Enforcement of Building Energy Efficiency Codes 10 Incentivizing Investors and Developers to Exceed Mandatory Standards 13PART II: RETROFITTING EXISTING BUILDINGS 14Retrofitting Municipal or Public Buildings 14Retrofitting Commercial Buildings 15Retrofitting Residential Buildings 17PART III: MANAGING ENERGY USE IN PUBLIC AND COMMERCIAL BUILDINGS 19CONCLUSION 20ENDNOTES 21REFERENCES 21ACRONYMS AND ABBREVIATIONS 22Improving Energy Efficiency in BuildingsiEXECUTIVE SUMMARYAbout one-third of global energy is consumed in residential, public, and commercial buildings (collectively referred to as buildings), where it is used for space heating, cooling, ventilating, lighting, cooking, water heating, refrigerating, and operating electric and mechanical devices. Global energy use in buildings is expected to grow as cities in developing countries continue to modernize and per capita income levels continue to increase.Because of their high energy consumption, residential, public, and commercial buildings also offer unparalleled opportunities for energy savings. According to the International Energy Agency, buildings account for some 41 percent of global energy savings potential by 2035, compared with the industrial sector (24 percent) and the transport sector (21 percent).1This guidance note outlines how cities can tap into a wide array of proven technologies, policies, and financing mechanisms to improve energy efficiency and capture cost-effective energy savings in buildings. It offers city leaders advice on how to get started in introducing energy efficiency measures, and provides lessons and examples from successful programs that have been introduced worldwide.There are three primary ways in which energy efficiency can be improved in residential, public, and commercial buildings:1 | Through improved design and construction techniques that reduce heating, cooling, ventilating, and lighting loads2 | Through building upgrades and the replacement of energy-using equipment3 | By actively managing energy useThe main junctures at which energy efficiency interventions can be launched are as follows:When designing and constructing new buildings. Well-designed and well- constructed new buildings represent the best opportunity for reducing heating, cooling, ventilating, and lighting loads. The most effective way to ensure that energy efficiency is factored into the design and construction process is by introducing and enforcing Building Energy Efficiency Codes. A building energy efficiency code sets out the minimum energy efficiency requirements of a building, including the thermal performance of a buildings “envelope” and the energy efficiency standards of its internal equipment and devices.By retrofitting existing buildings. Retrofitting existing buildings and replacing energy-consuming equipment are critical for improving energy efficiency in cities where building stock turnover is low. Cities need to be opportunistic in order to capture this potential by incentivizing and/or requiring energy efficiency upgrades as part of all significant renovations and equipment-replacement activities. For this to happen, an enabling environment and effective project financing and delivery mechanisms must be in place.By establishing and maintaining energy management systems. Establishing and maintaining effective energy management systems for monitoring and controlling energy use in large public and commercial buildings is a low-cost means with which to improve energy efficiency and reduce energy demand.There are a number of key barriers that must be overcome in scaling up energy efficiency in buildings. These include the high cost of gathering reliable information on a buildings Executive Summary1energy performance; a lack of technical capacity with which to design, construct and maintain energy efficient buildings; a lack of incentives to invest in energy efficiency; limited access to financing; and difficulties in coordinating the building sectors many stakeholders. Overcoming these barriers requires strong commitment and leadership from city authorities as well as a willingness to work closely with national and regional governments, building and home-owners, developers, financiers, the building trades and industries, and energy utilities.Cities looking to systematically improve energy efficiency in buildings should initially consider the following steps:Carrying out a rapid energy efficiency assessment of the building sector that identifies key opportunities and challenges, assesses stakeholders and resources, and determines priorities and next steps;Implementing energy efficiency initiatives in public buildingssuch as municipal offices, schools, and hospitalsin order