Building energy certification versus user satisfaction with the indoor environment: Findings from a multi-site post-occupancy evaluation (POE) in Switzerland

Voluntary green-rating systems exist in different forms worldwide to certify the sustainability of residential and commercial buildings and help national policies promote energy-efficient design practices. Despite the general assumption that sustainable buildings also provide high comfort and healthy conditions, existing studies on green-rated buildings led to controversial conclusions in this regard.This paper aims to report the results of a post-occupancy evaluation (POE) conducted on four Swiss green buildings certified with the Minergie label to analyse their ability in providing comfort to their occupants. The POE protocol included winter and summer environmental monitoring campaigns (long-term and instantaneous measurements) as well as extensive and point-in-time comfort surveys.From the study it was found that, although the observed environmental factors were most of the time complying with the norm prescriptions, the indoor conditions were never attaining the commonly used 80%satisfaction threshold by the users. Temperature and air quality appeared, in particular, as the most critical factors, with satisfaction rates never greater than 50% in three out of the four case studies.Design factors related to the personal control on the indoor environment as well as personal factors like gender, climate of origin and duration of residence in the country were also found to have an impact in the comfort rating.Professionals involved in the design and management of these buildings all agreed that feedback of this kind from building in use could help inform the design and operational process and move towards more effective green building certification systems and regulations.

The usability of green building rating systems in hot arid climates: A case study in Siwa, Egypt

Shady Galal Mohamed Attia

In the last three years there has been a proliferation of regional building rating systems across the Middle East. Most those emerging rating systems and labels imitate the British and American rating systems BREEAM and LEED that emerge from an impact reduction paradigm. Thus they are neglecting the local historic, climatic, economic, technological, cultural and social context. This paper presents two case studies of a recently constructed ecolodges in Siwa, Egypt, that performs beyond the existing rating systems requirements. The paper illustrates the environmental and sustainability design strategies adapted to El-Babinshal and Adrère Amellal buildings’ context. In this study, various design strategies are surveyed and their response to climate, occupants and society is evaluated. The paper presents a set of sustainability principles addressing (1) the site, (2) water, (3) energy, (4) resources, (5) comfort, (6) heritage and (7) social responsibility. In addition, the building is examined across the environmental criteria of LEED, Estidama and the Egyptian Green Pyramid Rating System. Results showed that the building failed to comply with the three rating systems despite winning the Egyptian Hassan Fathy Award for environmental design. The paper elaborates on this conflict and presents recommendations to improve the questioned rating systems and support architects with the principles and strategies for sustainable design.

2013

Refurbishment of Existing Envelopes in Residential Buildings: assessing robust solutions for future climate change

Giorgia Chinazzo

Evaluating the energy consumption of different design solutions during the design process is essential to reach energy targets. Conventionally, building energy performance is evaluated with energy simulations using a single input weather file (design or typical year) referring only to present weather conditions. Recent works, for example by Gaterell at al. for sites in the United Kingdom, suggest, however, that it is necessary to also include weather files describing climate conditions in future years. That is, the effect of predicted climate change on building performance. Buildings have a life span of 50 to 100 years and so must perform satisfactorily under both current and future climate, adjusting to take advantage of opportunities and to moderate potential damage caused by a changing climate (Wilde et al. 2008). Given the fact that climate is a singularly stochastic phenomenon and that we cannot predict the weather in future years with complete certainty, weather inputs necessarily have intrinsic uncertainties. Using a single weather file in building simulations, regardless of its source or generative algorithm, could lead to inaccurate energy consumption forecasts, and therefore wrong design decisions. In any case, the development of typical weather files was not always done keeping in mind forecasting, but rather what-if analyses. The innovation in our study consists in the introduction of more than one input weather file in building simulation to represent both present and future years. Our methodology aims to assess the robustness of different design solutions over many possible future climate projections, i.e. the sensitivity of a design or device to uncertain climatic outcomes. We focus on the robustness of refurbishment measures compared to the robustness of the non-refurbished building. We assess each intervention in terms of energy consumption. We decided to focus on existing buildings since they represent the biggest opportunity to reach energy targets today in Europe. In fact, the majority of the European building stock was constructed before any energy regulations and tends to perform poorly for energy consumption and comfort. We propose three indices to make comparisons between refurbishments. The Robustness Index (RI) compares the robustness of the each solution in terms of its range of energy usage. The Energy Saving Index (ESI) assesses the refurbished models in terms of energy usage difference in comparison with the non-refurbished model or base-case. The Gather Index (GI) summarizes the results of the two previous indices to compare the performance of the different refurbishments in terms of both robustness and energy efficiency. As a case study, we evaluated the robustness of an existing dwelling with twenty-two realistic refurbishments in Turin, Italy. The retrofit solutions focus on the thermal properties of the envelope by varying the U-value, the solar heat gains, the thermal mass and the air tightness of the envelope. The main outcome of our study is that interpreting numerical simulations of future energy consumption based on single-point estimates of input/output data (i.e. one typical weather file) is risky. Results are better treated as being probabilistic rather than deterministic, as is the norm today. Discussing outcomes in terms of ranges instead of single values improves estimates of outcomes, making it possible to identify robust design solutions for policy and investment decisions.

2014

Architectural strategies to integrate wellbeing and health effects of daylight into the design of primary schools: a comparative analysis of exemplary case studies

Jean-Denis Bernard Marie Ghislain Thiry

Starting from an architect’s point of view, the aim of this research is to combine the daylight performance of educational spaces with a broader spatial, cultural, and historical approach. Through a rigorous study of school typologies, the geometry of their spaces, and their associated daylighting strategies, this work aims to connect design practitioners with aspects of health and well-being for the pupils, as far as these aspects are related to the quality of daylight. The proposed methodology seeks to analyse a range of outstanding case studies from the masters of modern architecture, embodying architectural strategies specifically designed to ensure adequate illuminance levels in learning areas throughout the day. A selection of some singular primary schools will be established through a historical analysis which emphasizes the impact of hygienists’ principles – legacies of Modernism – on the evolution of plans and volumes of different school typologies in Switzerland and Europe, from 1945 to the present days. An analysis of the selected case studies will be carried out using an innovative representation method of average illuminance received at eye-level and combined with a HLR model – currently under development at LIPID [1, 2] – which assesses the health potential of daylight using a dynamic approach. Through a validation of the simulated results using different in situ measurements and analyses following a specific protocol, we aim to accurately identify architectural criteria and propose strategies for achieving “circadian design”, more specifically those having a positive impact on the health and wellbeing of occupants. We will also carry out a comparative critical assessment of the buildings selected as case studies in the initial phase of this proposed research. The goal is to positively influence decisions related to the design of naturally lit spaces, specifically in schools and according to their impact on health, wellbeing and student productivity. The methodology will be a complementary blend of observations, in situ measurements and qualitative and quantitative analyses, both in a simulated environment and in actual working conditions of the selected case studies.