**3. Energy-efficient architecture in sustainable urban tourism**

Architecture and spatial planning are important elements of urban tourism. Recognition of the existing architectural heritage and responsible planning and design of architecture and urban space according to the sustainable development principles contribute significantly to the development of sustainable urban tourism, as well as tourism in general.

Tourism is the fastest growing economic sector in the world [34], with urban tourism among the fastest growing segments [35].

Tourists are drawn to the cities attracted by the diversity on offer in cities worldwide. It is unquestionable that their arrivals contribute to the local economy making a strong socio-economic impact. All participants involved in tourism planning and development today should clearly be aware of the necessity to reduce the environmental impact.

This certainly applies to the architecture in tourism, since hospitality industry is among the largest polluters and resource consumers.

Sustainable urban planning and sustainable architecture are prerequisite to sustainable urban tourism development. All relevant stakeholders should consider the environmental, social and economic impacts, highlighting the conscientious use of resources especially the nonrenewable energy and water, waste minimisation and application of energy-efficient systems and optimisation of technology solution.

Hotels, directly and indirectly, affect the environment. Energy, water and raw materials are consumed during construction, building use, maintenance, renewal and destruction. In addition, waste is generated and harmful substances are released into the atmosphere during those processes. These facts prompted the creation of standards and certification systems aimed to mitigate environmental impact in accordance to the principles of sustainable development.

In the 1990s, the first so-called green building was certified in the United States by the Building Research Establishment Environmental Assessment Method (BREEAM). In 2000, the US Green Building Council (USGBC) defined the certification criteria to improve energy efficiency and environmental protection and set up a Leadership in Energy and Environmental Design (LEED). Under the influence of BREEAM and LEED systems, other systems have been developed, tailored to national priorities and needs and some of them coming out as the usual framework of building practice and existing legislation, applying the principles of sustainable development and concepts such as building of nearly-zero energy use or passive-solar buildings.

Hotel certification systems were initiated with the aim to manage the hotel's environmental impacts, both globally and locally. Those systems were focused on: reduction of water and non-renewable energy consumption; environmentally sound waste management; protection and preservation of natural habitats; sustainable building and operational practices; responsible resource response with zero-waste strategies; effective damage and accident control at the construction site; self-sustainability with the utmost utilisation of renewable energy sources and passive solar systems; sustainability of all phases of the construction process; the use of environment-friendly materials; indoor air quality; promoting the concepts of sustainability among hotel guests, employees, suppliers and business partners with implementation of positive operational procedures; responsible attitude towards cultural heritage and biodiversity; partnerships with non-governmental organisations and the local community; socially responsible behaviour with the inclusion of community members.

Furthermore, the necessity for the high-quality hotel certification systems is the 'Greenwash' prevention. The most widespread and most common form of 'greenwash' is a hidden trade, lack of evidence, inaccuracy, irrelevance, inaccurate data on origin and content of recycled materials, possession of internationally recognised certificates, false labels on materials (such as, 'ecologically' on products containing pesticides and other toxins) and the alike.

In addition to the above-mentioned BREEAM and LEED systems, the following systems should be highlighted: Certified Passive House Building (by International Passive House Association [iPHA]), Deutsche Gesellschaft für Nachhaltiges Bauen (DGNB), Excellence in Design for Greater Efficiencies (EDGE), Energy Star, Green Building Evaluation Label (NR China) and nearly Zero Energy Hotel (neZEH, UK).

In 2016, the web site greenhotelworld.com announced the results of 'Certified Global Green-Hotel Density' research. The research was based on just over 130,000 hotels worldwide certified by a total of 50 hotel certification systems, in accordance with the standards set by the Global Sustainable Travel Council (GSTC). The established standards wanted to objectify green-hotel certification systems globally, as a support and incentive for sustainable tourism development. According to the research results, global density is 6.2%, while densities per continents are North America, 10.1%; South America, 2.7%; Europe, 6.1%; Oceania, 4.8%; Africa, 3.7% and Asia, 0.9%. Data show insufficient density of green hotels, both globally and regionally [36].
