Reduction of carbon emissions is understood to be vital to help mitigate catastrophic climate change. In Europe, 40% of energy use is attributed to the built environment (European Commission, 2010), with a large proportion of this from dwellings. In line other legislation for decarbonisation under the Climate Change Act of 2008, the UK Government has agreed that all new housing will be ‘zero carbon’ from 2016 onwards. From a technical aspect this task is feasible using improved insulation performance, more airtight building techniques, efficient servicing, and renewable energy technologies. In practice however, post-occupancy evaluation studies highlight a discrepancy between design energy use and measured energy performance, with a tendency for real buildings to use more energy than designed and for projects regarded as ‘low energy’ in design to use an equivalent amount of energy as a pre-existing counterpart (Bordass, 2001; Branco, Lachal, Gallinelli, & Weber, 2004; Gill, Tierney, Pegg, & Allan, 2011). This difference between design and use - ‘the design gap’ - is attributed to both the physical ‘hard’ features of the building (form, area, systems) and occupant-driven or ‘soft’ features (ventilation & heating preferences) by a number of studies (Guerra Santin, Itard, & Visscher, 2009; Socolow, 1978). This body of work begins with a review of the field and state of the art - occupant influence on energy use in a domestic environment. The first contribution to knowledge is in the adapted utilisation of a piece of software by Richardson et al. which stochastically generated electricity use profiles for homes which are shown to be similar to measured energy usage, both in net energy use and in load profiles (Richardson, Thomson, & Infield, 2008). This adapted software was implemented to generate appliance use profiles for a number of dwelling models. These results are then interrogated and a regression model proposed based on a number of dependent variables identified in the input profiles. The theory of planned behaviour is used to underpin a survey in which a number of households are asked to comment on their attitude and behaviour with regards to energy use in the home – the homes in this case being new-build Passivhaus council-housing in Devon. The results of this project form the second aspect of this work’s contribution to knowledge.

The Passivhaus standard is a building methodology that was established in Germany in the 1990s. It uses a passive design strategy to achieve built environment comfort with minimum energy consumption. However, research shows that not every Passivhaus project has been successful in terms of its comfort and energy performance. Passivhaus is a representation of a high-performance, low-energy prototype of sustainable buildings, which, as a new building typology, embraces new ideas of comfort and accommodates a range of occupants who have different attitudes and expectations. Thus, the social grounding of such a new typology needs to be reconsidered. Understanding the phenomenon of Passivhaus living in the UK context forms the starting point of my research. In reflection of existing Passivhaus post-occupancy evaluation (POE) research in the UK, the majority of this research is focused on performance and frequently adopts an approach using prediction and computer simulation. Only a few studies have examined the Passivhaus system from an architectural design point of view. Research into its energy performance lacks a deeper connection with the occupants' perception of comfort and the architectural design of the Passivhaus. This research focuses on the coherence of Passivhaus living and builds up a theoretical framework to understand the Passivhaus system in relation to occupants' daily lives. It argues that by providing more possibilities and opportunities within the design of the built environment for adaptive behaviours and norms of sustainable living, as opposed to stressing energy efficiency and technological advances, the sustainability embodied in the Passivhaus standard can be further actualised. Previous research into the POE field of Passivhaus has employed a predominantly quantitative method. However, the small amount of research conducted using a qualitative approach demonstrates the potential benefits of gaining a better understanding of sustainability in people's perceptions of comfort, their everyday practices and the nature of their energy use. The methodological approach for the proposed research will be qualitative in nature due to the need to understand highly context-bound experiential data. A mixed approach of quantitative and qualitative methods will be explored to collect and analyse data from various aspects related to the subject matter in order to draw valid conclusions. The research uses a combined framework of grounded theory methodology and a multiple case study approach as a way of taking a step back from empirical research and building up an inductive theory-building process. The combination of these two frameworks is tailored for this research, which enables them to complement each other. The research provides an exploration of Passivhaus living and an insight into the delicate relationship between the occupants and their domestic space. The study explores the shifting perception of comfort, the delicate relationship between habitat and inhabitant and the process of adaptation in the Passivhaus to understand the shaping of household behaviour in relation to different contexts and scenarios unique to the Passivhaus industry. The substantive theory that describes this relationship is summarised at the end of the thesis, with the aim of informing potential Passivhaus clients of the system's holistic sustainable design features and to make recommendations for better Passivhaus design to building professionals.

Domestic gas consumption for central heating is a function both of the efficiency of the heating system and the way in which it is used. While many studies have concentrated on the performance of systems and their controls, there have been few studies of occupant behaviour. The thesis therefore studies household behaviour patterns relating to domestic gas consumption. There are two main aims: firstly, to study a variety of these patterns and, secondly, to make a detailed investigation of one particular behaviour pattern, namely window opening. These two studies centre on 113 households on two local authority estates, where all the dwellings are of similar construction. The first study makes use of two main data sources: quarterly gas consumption readings and data obtained from an in-depth interview with each head of household. It identifies a variety of behaviour patterns and their underlying motivations. Additionally, this study shows that design heat loss and terrace position account for less than a third of the variance in winter consumption. A regression analysis using only behavioural and social variables resulted in a similar proportion of variance being explained. These two sets of independent variables could not justifiably be combined due to their inter-correlations. In conclusion, it was suggested that consumption may not be determined by a few variables of major significance but rather by a large number of inter-acting variables each with a small influence on consumption. The second study, window opening, makes use of three data sources: a series of systematic window observations, meteorological data and data obtained from postal questionnaires. The study identifies the objective correlates of estate-wide window opening, as well as the subjective motivations for the opening and closing of windows. It highlights the wide range of variation in window opening amongst householders. In addition, the study indicates that householders adopt characteristic window opening patterns which they can reliably report.

About 12% of the greenhouse gas emissions and 40% of the total energy use in the EU derive from the buildings. User behavior, construction, and HVAC systems has a significant impact on a building’s energy use. If a building is to be energy-efficient it is important to understand how all these parameters are connected. This study is motivated by the need to decrease the energy use in buildings to reach the goals of energy use and greenhouse gas emissions.  In this thesis, measurements of indoor climate and electricity use, together with time diaries was used to create input data for an energy simulation model of a retirement home. A parametric study was conducted to simulate how energy demand was affected by changes in five different parameters in an office building. Also, two different energy-efficiency indicators were used to see how indicators can affect the perceived energy-efficiency of buildings. High amount of airing and low electricity use had the most impact on the heating demand in the retirement home, and electricity use had the highest impact on the total energy demand in the office building. The model of the retirement home using data gathered on-site had 24% higher energy use than the model using standard user input data. In the office building, total energy demand for heating and cooling could be lowered with 12-31% by lowering the electricity use with 30% compared to standard user input data. For office buildings the most important thing to lower total energy demand seems to be lowering the electricity use. Using today’s standard user input data does not correspond well to using on-site gathered data in a retirement home and it is therefore important to develop the standard user input data further. The indicator kWh/m2, seems to promote buildings with low occupancy. This could lead to buildings being utilized in an in-efficient way. The indicator kWh/m2 should either be replaced or combined with an indicator that takes occupancy into consideration. / Runt 12% av utsläppen av växthusgaser och 40% av den totala energianvändningen i EU kommer från byggnader. Brukarbeteende, konstruktion och HVAC-system har signifikant påverkan på en byggnads energianvändning. Om en byggnad ska bli så energieffektiv som möjligt är det viktigt att förstå hur dessa parametrar hör ihop. Denna studie motiveras av behovet att minska energianvändning i byggnader för att nå målen för energianvändning och utsläpp av växthusgaser.  I denna avhandling användes mätningar av inomhusklimat och elanvändning, tillsammans med tidsdagböcker, för att skapa indata till en energisimuleringsmodell av ett ålderdomshem. En parameterstudie genomfördes för att simulera hur energibehovet påverkades av ändringar i fem olika parametrar i en kontorsbyggnad. Två olika indikatorer för energieffektivitet användes också, för att se hur olika indikatorer påverkar hur en byggnads energieffektivitet uppfattas. Hög grad av vädring och låg elanvändning hade störst påverkan av energibehovet i ålderdomshemmet, och i kontorsbyggnaden påverkades det totala energibehovet mest av elanvändningen. Modellen av ålderdomshemmet där data insamlad på plats användes hade 24% högre värmebehov än modellen som använde standardiserade brukarindata. Det totala energibehovet för värme och kyla i kontorsbyggnaden kunde sänkas med 12-31% genom att sänka elanvändningen med 30% jämfört med standardiserad brukarindata. Det viktigaste för att få ner det totala energibehovet i kontorsbyggnader verkar vara att sänka elanvändningen. Att använda dagens standardvärden för brukarindata överensstämmer inte väl med att använda data insamlad på plats för ett ålderdomshem. Det är därför viktigt att vidareutveckla standardiserad brukarindata. Indikatorn kWh/m2 verkar främja byggnader med låg beläggning. Detta skulle kunna leda till att byggnader utnyttjas på ett ineffektivt sätt. Indikatorn kWh/m2 skulle därför behöva ersättas eller kombineras med en indikator som även tar byggnadens beläggning i beaktande.

This Engineering Doctorate aims to understand the factors that generate variability in small power consumption in commercial office buildings in order to generate more representative, building specific estimates of energy consumption. Current energy modelling practices in England are heavily focussed on simplified calculations for compliance with Building Regulations, which exclude numerous sources of energy use such as small power. When considered, estimates of small power consumption are often based on historic benchmarks, which fail to capture the significant variability of this end-use, as well as the dynamic nature of office environments. Six interrelated studies are presented in this thesis resulting in three contributions to existing theory and practice. The first contribution consists of new monitored data of energy consumption and power demand profiles for individual small power equipment in use in contemporary office buildings. These were used to inform a critical review of existing benchmarks widely used by designers in the UK. In addition, monthly and annual small power consumption data for different tenants occupying similar buildings demonstrated variations of up to 73%. The second contribution consists of a cross-disciplinary investigation into the factors influencing small power consumption. A study based on the Theory of Planned Behaviour demonstrated that perceived behavioural control may account for 17% of the variation in electricity use by different tenants. A subsequent monitoring study at the equipment level identified that user attitudes and actions may have a greater impact on variations in energy consumption than job requirements or computer specification alone. The third contribution consists of two predictive models for estimating small power demand and energy consumption in office buildings. Outputs from both models were validated and demonstrated a good correlation between predictions and monitored data. This research also led to the development and publication of industry guidance on how to stimate operational energy use at the design stage.

L’amélioration continue de la performance énergétique des bâtiments a été accompagnée par un développement d’outils numériques de plus en plus performants et précis. Alors que la prise en compte des phénomènes liés aux bâtiments, aux systèmes et à la météorologie est bien maîtrisée, le comportement des occupants est modélisé de manière très simplifiée par des scénarii répétitifs et des lois déterministes. L’impact des occupants sur les consommations énergétiques dans les bâtiments performants est pourtant majeur, comme en témoigne les écarts récurrents entre les résultats prédits et mesurés. Le travail de thèse propose, par l’intermédiaire d’une plateforme multi-agents et de modèles stochastiques, une mise à jour de la prise en compte de la présence des occupants et de leurs comportements sur la gestion des ouvrants, des dispositifs d’occultation, de l’éclairage et de la température de consigne de chauffage. Le champ d’application de la plateforme concerne les bâtiments de bureaux et de logements, pour des opérations neuves et de rénovation. Les modèles de comportement des occupants sont idéalement issus de campagnes de mesures in situ, d’études de laboratoire ou d’enquêtes sociologiques. La plateforme proposée est alors co-simulée avec le logiciel EnergyPlus, afin d’étudier l’influence des modèles sur les performances énergétiques. Dans la perspective de garantie de performance énergétique, ce travail contribue à la mise à jour et à la fiabilisation des outils de prédiction. / Continuous improvement of the building energy performance is associated with the development of increasingly efficient and accurate numerical tools. While the consideration of phenomena related to buildings, systems and weather is well mastered, occupants’ behaviours are modelled in a very simplified way by repetitive scenarios and deterministic laws. The impact of occupants on energy consumption in high-performance buildings is dominant, as evidenced by the recurring gaps between predicted and measured results. The thesis demonstrates, via a multi-agent platform and stochastic models, an update on the ability to model occupants’ presence, their behaviours on windows, occultation devices, artificial lighting and heating setpoint temperatures. The application of the platform applies to office and residential buildings, for new builds and refurbishments. Occupants’ behaviour models are ideally obtained from in situ surveys, laboratory studies or sociological works. The suggested platform is then co-simulated with the EnergyPlus software, to study the influence of the models on a buildings energy performance. In the perspective of energy performance guarantees, this work contributes to the updating and reliability of prediction tools.

Les demandes des usagers conjuguées à la réglementation nécessitent de concevoir des bâtiments de plus en plus confortables et économes en énergie. En parallèle de ces exigences, les réglementations concernant les bâtiments sont renforcées dans différents domaines (acoustique, sécurité incendie, risque sismique,…) afin d’obtenir des bâtiments plus sûrs et correspondant aux demandes des usagers. Les impacts conjugués de ces deux facteurs engendrent une complexification de la conception des bâtiments.Cette thèse présente une démarche d’aide à la connaissance pour la conception de bâtis performants se basant sur une méthode d’optimisation. Cette démarche vise à ce que les architectes et les bureaux d’études aient une connaissance claire du potentiel de leur projet (exploration de solutions) en phase amont de conception, pour concevoir des bâtiments les plus performants possibles. Ce potentiel est évalué via des paramètres de la géométrie extérieure et intérieure ainsi que des caractéristiques énergétiques du bâti. La démarche leur permet également d’évaluer les avantages et inconvénients de différentes géométries et solutions de conception qu’ils envisagent pour répondre à leurs projets. Cette démarche est appliquée à un immeuble de bureaux à Lyon.Pour le cas testé, la démarche permet d’obtenir rapidement des solutions performantes et de définir pour certains des paramètres étudiés, des valeurs conduisant aux solutions performantes dans une partie de l’espace des solutions ou dans l’ensemble de cet espace.Cette application de la démarche montre également qu’il peut exister des solutions ayant des besoins énergétiques et des coûts de construction proches mais étant très différentes en termes de paramètres de conception. Bien que remettant en cause l'applicabilité directe de la démarche, ce résultat met en exergue un problème nouveau. Cette thèse pose alors les bases pour une nouvelle étude. / Both aspirations of users and improvements in the thermal regulation require that the comfort and the energy efficiency of new buildings improve. In addition to these requirements, regulations are strengthening in many fields such as acoustics, fire safety and mechanical performance. The combined effects of these factors are making it increasingly hard to design buildings. This thesis presents a knowledge-aid approach for designing high-performance buildings based on an optimization method. This approach aims to provide clear knowledge of the potential of projects (exploration of various options) for architects and design offices at the beginning of the design that will allow them to design the best possible high-performance buildings. This potential is evaluated using external and internal geometric parameters as well as the energy characteristics of buildings. This approach also allows them to assess geometries and design solutions which are intended to be used for their projects.This approach will be applied to an office building in Lyon, France. For the tested case, the approach obtains quickly efficient solutions and also finds, for some parameters, values to design efficient solutions on part of the Paretofront or in this entire front. This application of the approach also shows that there may be solutions which are close in terms of energy needs and cost but could be very different on design parameters. This problem could influence robustness of the approach but highlights a new problem. This thesis then lays the foundation of a new study on this topic.