## 1 Introduction  
CO\({}_{2}\) emissions, global warming, air pollution, resource depletion, and growing population are serious and threatening challenges facing humanity nowadays. In fact, at the current population growth rate and increasing energy demand for housing and improving quality of living standards, it is predicted that the current primary energy sources will be depleted in less than 134 years [1]. One of the major contributors of CO\({}_{2}\) emissions and energy consumers is buildings. For instance, the building sector in the U.S. and Europe represents 39% and 40% of the energy consumption and 38% and 36% of the CO\({}_{2}\) emissions, respectively [2]. Buildings consume energy mainly for lighting, electrical equipment, and mainly thermal comfort (cooling, heating), which represent a large proportion of building energy consumption [3]. As a result, governments, private institutions, environmentalists, and researchers around the globe are researching ways to reduce the adverse effects of consuming energy and emitting CO\({}_{2}\) by creating strategic plans, national frameworks, building codes, and energy performance rating systems to help existing as well as new buildings become zero-energy buildings (ZEBs). Actually, zero-energy buildings can be defined as energy-efficient buildings that are able to generate electricity from renewable sources to help satisfy part or all of their demand. Net ZEBs, which are mainly buildings connected to the grid, have different definitions according to the specific country conditions and political and energy targets. In [4], the authors built a definition framework for net ZEBs based on the import/export and the load/generation balances, where the word \"net\" refers to the building balance between supply and demand. In general, a ZEB refers to two main strategies [5]:  
* Minimizing building energy consumption by adopting energy-efficient measures and retrofits for the building envelopes (i.e., insulation), internal conditions (i.e., heat loads), and building service systems (i.e., HVAC);
* Generating energy from renewable sources to meet the building energy needs, such as building-integrated photovoltaics (BIPVs), wind turbines, solar thermal sources (solar water heaters), and heat pumps. In another paper, the authors extend the definition of a ZEB to cover the whole life cycle of the building [6], where the energy used in the building operations and embodied within its systems and components should be satisfied by the building's renewable energy over its lifetime. To refer to the previous definition, the authors propose the term \"life cycle zero energy building\" (LC-ZEB), which has an annualized life cycle energy (ALCE) (the sum of the annualized embodied energy (AEE) and the annual energy use (AEU)) that is equal to zero. Many countries around the world are trying to adopt ZEBs with different levels of commitment. USA, Canada, Japan, and the European Union member states are arguably early adopters of ZEB public policies. For instance, many European public policies support the nearly zero energy building (NZEB) objective (Directives 2010/31/EU and 2018/844/UE) and also support its evolution, such as the Horizon 2020 EU programs, which promote the positive energy building (PEB) model, where buildings produce more energy than their needs and can help fulfill the needs of other buildings that are connected to them [7]. In some other countries (considered developed), such as Australia, a lack of specific policy and support to nearly ZEBs is exhibited and better codes and targeted policies are required to achieve nearly ZEBs, especially with their existing high penetration of renewables [8]. In the case of developed countries, the adoption of ZEBs is still in its early stages. For example, China, as the most populous country and the biggest carbon emitter in the world, has a national standard to promote the development of nearly ZEBs, with 37 local governments having implemented ZEB policies and 13 local governments offering subsidies [5].