The concept of Smart Buildings was introduced by the Energy Performance Building Directive, with the aim to promote energy flexibility, renewable energy production and user interaction. A wide range of definitions have been introduced in the literature to characterize smart buildings yet, at present, its’ concept and features are not clearly and uniquely defined. Simultaneously, building energy retrofit concept has been introduced to facilitate achieving the nearly Zero-Energy Building target and reduce energy consumption in existing buildings. Up to 90 % of the existing European building stock will still be standing and in use in 2050. Thus, there is a need to upgrade the existing retrofitting strategies into Smart Retrofitting, to achieve the nearly Zero Energy Building target and be able to respond to external dynamic conditions such as the weather and the grid. The aim of this research is first to review the concept of smartness in the built environment, highlighting the main features, functions, and technologies of smart buildings, also discussing the possible challenges for smart retrofit applications. The second part of the paper reviews the existing Key Performance Indicators that measure the performance and success in achieving goals in smart buildings. The need to develop a quantified guideline to improve energy and technological innovation is the basis for the increase of the smartness in buildings. Consequently, a set of nine groups of representative performance indicators for smart buildings is developed. This work shows current gaps in the literature and highlights the space for foreseeable future research.

智能建筑的概念是由《能源性能建筑指令》引入的，旨在促进能源灵活性，可再生能源生产和用户互动。文献中已经引入了各种各样的定义来表征智能建筑，但目前，其概念和功能还没有明确和唯一地定义。同时，引入了建筑节能改造概念，以促进实现接近零能耗的建筑目标并减少现有建筑的能耗。到2050年，仍将有90％的欧洲现有建筑物存留并投入使用。因此，有必要将现有的改造策略升级为智能改造，以实现几乎零能耗的建筑目标，并能够应对外部动态条件，例如天气和电网。这项研究的目的是首先回顾建筑环境中的智能概念，重点介绍智能建筑的主要特征，功能和技术，并讨论智能改造应用程序可能面临的挑战。本文的第二部分回顾了现有的关键绩效指标，这些指标衡量了智能建筑实现目标的绩效和成功程度。制定量化指南以改善能源和技术创新的需求是提高建筑智能性的基础。因此，开发了一套九组具有代表性的智能建筑性能指标。