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International audience ; The European energy and political context suggests that households will have to face up to making significant reductions of their energy consumption over the coming decades. Indeed European Union has adopted a 20 % reduction in energy consumption by 2020 in its climate energy package. The aim of this paper is not only to study the refurbishment and technological changes implied by such targets but also to show its impact on household budget as this ambitious target may imply strong efforts from households. Studies that deal with efficiency of policy tools generally adopt a global economic point of view and rarely consider dis-tributional impacts on final consumers and if so, do not consider possible differences in consumer behavior patterns regarding energy use. How can we therefore assess the suitability of such policies without clearly anticipating their repercussions on households, whose behavior is obviously heterogeneous? In order to provide useful insights about the impact of such policies on residential sector, it appears crucial to capture both household heterogeneity and household behaviour in long-term planning models. Our analysis relies on the TIMES-Households model which is a bottom-up optimization model from the MARKAL/TIMES family of energy models that allows for a very significant disag-gregation of demand and technological processes. The building stock and its inhabitants are then represented in a very detailed manner considering both technical and socio-demographic characteristics. Moreover, thanks to analyses picked from a detailed household survey we are then able to differentiate access to technologies, level of energy demand and equipment purchasing behaviour according to household characteristics (income, size, type of housing, occupation status). We show the impact on household budget of the 38 % reduction target of primary energy consumption in residential building stock by 2020 adopted by the French government.

International audience ; The European energy and political context suggests that households will have to face up to making significant reductions of their energy consumption over the coming decades. Indeed European Union has adopted a 20 % reduction in energy consumption by 2020 in its climate energy package. The aim of this paper is not only to study the refurbishment and technological changes implied by such targets but also to show its impact on household budget as this ambitious target may imply strong efforts from households. Studies that deal with efficiency of policy tools generally adopt a global economic point of view and rarely consider dis-tributional impacts on final consumers and if so, do not consider possible differences in consumer behavior patterns regarding energy use. How can we therefore assess the suitability of such policies without clearly anticipating their repercussions on households, whose behavior is obviously heterogeneous? In order to provide useful insights about the impact of such policies on residential sector, it appears crucial to capture both household heterogeneity and household behaviour in long-term planning models. Our analysis relies on the TIMES-Households model which is a bottom-up optimization model from the MARKAL/TIMES family of energy models that allows for a very significant disag-gregation of demand and technological processes. The building stock and its inhabitants are then represented in a very detailed manner considering both technical and socio-demographic characteristics. Moreover, thanks to analyses picked from a detailed household survey we are then able to differentiate access to technologies, level of energy demand and equipment purchasing behaviour according to household characteristics (income, size, type of housing, occupation status). We show the impact on household budget of the 38 % reduction target of primary energy consumption in residential building stock by 2020 adopted by the French government.

International audience ; Recent European energy policies like the Energy Efficiency Directive (EED) and the EcoDesign Directive (EDD) set new targets to increase energy efficiency. Article 7 of EED implies that EU Member States set up energy savings amounting to 1.5 % of the annual energy sales to final customers from 2014 to 2020. To comply with this requirement the level of French White Certificate (WC) obligation should double in the next period. Moreover, the EDD directive sets the minimum energy efficiency level only for a limited number of equipment such as boilers, heat pumps and water heater. In this regard, the WC scheme deemed savings must be revised in order to comply with the European calculation rules of EED's Annex 5. Certain adjustments must be made to the French WC which has been enforced since 2006 and is entering its third period (2015-2017) to be in tune with these directives. Thus, the WC scheme undergoes a revision of unitary savings differentiating between devices already covered by EDD (e.g. boilers) and appliances which are not (e.g. windows). The outcome is a blend of different references (stock, market) and savings (total, marginal) depending on the considered unitary action. Consequences could be a lack of clarity especially for non-specialists of energy policy. This paper addresses the question of a possible conflict of interests between the European system, allocating savings by directive, and the overall customer savings. Scenarios embedded impacts of the new European rules on the WC market are quantified in order to answer the question: will the third period of WC give a positive signal to the refurbishment market? The overall revising process of the third period of WC and its consequences will be presented concerning the building sector. More precisely, calculations to quantify impacts on unitary action savings, on WC costs and on the retrofitting market structure are detailed. Finally, suggestions are proposed that enable both the enhancement of energy efficiency at the European ...

International audience ; The French EPC (Energy Performance Certificate) was implemented in 2006 to be mandatory for selling or renting a dwelling. From the beginning, the EPC's robustness was questioned. Field tests showed that, for the same building, two different energy labels could be obtained from auditors. Thus in 2012 the EPC was revised to make it more reliable by, among others , doubling the number of inputs in the calculation method. Unfortunately, recent investigations show that the problems persist whereas a law plans to make EPC enforceable against third persons in 2021. In this way, the French government has announced a new rework of the EPC for 2019. In this context we study the part in the dispersion of EPC's results due to the calculation method. In 2011 a first study consisted of an uncertainty propagation (Monte-Carlo method) and a sensitivity analysis in the initial version of the calculation method (2006 method) on the case of a single-family house. Using the same case and the same methodology (and also Sobol method), we are able to compare the differences between the initial and revised calculation methods. The revised version is not more accurate and some main sources of dispersion in the EPC's results are identified: • in all input modes, estimated energy consumption has increased while the EPC is known to overestimate actual consumption , • we observed a doubling of consumption's dispersion, • significant differences in results exist between the input modes ("precise input" vs. "default value" with threshold effects in the value tables), • a large part of discrepancy depends on the uncertainties on transmission coefficients of the thermal insulation and on the surface area. In conclusion, in association with the question of the qualification of diagnosticians, the calculation method must be deeply reworked so that the EPC becomes the main tool of the building stock refurbishment.

International audience ; The energy performance of a building can be assessed using various indicators that will not give the same score. This study evaluates the performance of the French housing stock using several indicators based either on the energy level at which energy consumption is assessed (primary, final or useful), or on greenhouse gas emissions, or on the energy bill. An indicator calculated at each of the 3 stages of the energy chain allows a sequential approach to building performance: the "useful energy" level measures the performance of the thermal insulation of the envelope, the "final energy" level adds the consideration of the performance of equipment providing energy services, and the "primary energy" level combines the performance of energy sources. The paper focuses on the comparison of French (DPE, Diagnostic de Performance Energétique, French Energy Performance Certificate) and UK (EPC, Energy Performance Certificate) indicators. The European Union has widely disseminated the EPC for housing through the EPBD 2002/91/EC (Energy Performance of Buildings Directive, then revised in 2010 and 2018). Originally, with the exception of the number of seven energy classes, Member States were free to choose the details of the calculations of their "national" EPC. Most European countries including France-have chosen an absolute value scale to define performance ranges and a primary energy indicator for energy performance. The United Kingdom has chosen an indicator related to the energy bill and expressed on a standard scale. The impact of the different approaches proposed for evaluating the performance of the French housing stock is analysed. The relevance of the indicators is discussed according to two criteria: the nature of the actors to whom the evaluation is addressed (households, planners, politicians), and the objectives of the actions that the evaluation should guide (improving housing performance, reducing energy consumption, Green House Gas emissions (GHG), or energy bills). The results are ...

National audience ; Deux des objectifs importants des politiques énergétiques européennes et françaises sont la réduction de la dépendance énergétique et des émissions de gaz à effet de serre. La « MDE » (maîtrise des consommations d'énergie) fait partie des actions incontournables pour atteindre ces deux objectifs. Les bâtiments sont le premier secteur de la demande en énergie en France. Il est désormais reconnu que les objectifs de réduction drastique de leur consommation d'énergie et des émissions de CO 2 passent par une rénovation intensive du parc de logements existants. Une estimation des coûts techniques (investissements) liés aux scénarios étudiés est proposée. A horizon 2030, ce travail explore différents scénarios de rénovation du parc de logements [rythmes tendanciels et accélérés, techniques « standard » ou « MTD » (meilleures technologies disponibles)] en introduisant, en complément des solutions actuelles, quelques techniques encore peu développées qui pourraient jouer un rôle important pour atteindre un objectif « facteur 4 » à 2050. Les scénarios sont modélisés à l'aide du logiciel MIeL « Modélisation de l'Impact de mesures Energétiques sur les Logements », développé par EDF et construit sur une démarche bottom-up. Mots-clés : MIeL, MDE, Modélisation.

International audience ; This paper tackles the crucial issue of price structure in the energy retrofit market of the private residential sector. It is based on a quantitative study of retrofit prices in France (1,000+ invoices) and a qualitative sociological survey of installers (25 open-ended interviews). We show a strong dispersion of prices within single retrofit-work categories (e.g. boiler, insulation). Half of the dispersion is explained by technical and economic reasons (brand and quality of product, housing size, type of company, discount…). This means that from a technical standpoint, the price is correct. Other components of the price are revealed by the qualitative survey. On the customer side, the refurbishment market is marked by a strong uncertainty. It is technically complex and there is a concern about poor workmanship, hence the role of reputation and trust. These are factored in the price as a " confidence premium " which makes the price fair from the customers' point of view. On the installer side, the price is formed at the crossroads of three characteristics: the perception of the household willingness to pay, the management practices of the company (profit margin calculation, load plan) and an adjustment to current local market prices. The fair price from the installer point of view is the price that allows his company to survive or make profit and to win new contracts. However, a determining factor of the price lies in the installer's recommendation of exactly which work to do and with which material or equipment. For a given energy performance, several technical solutions exist that impact the final price. To conclude, we note that observed prices may differ from the technically " correct " price but this doesn't mean that prices are inaccurate. Prices incorporate qualitative dimensions such as the accessibility of the site or the work quality of the company (being on-schedule, cleanliness of the work, etc.) that make them " fair " in practice. As a policy consequence, rather than a direct intervention on prices which is complex, governmental action might focus on standardizing the presentation of quotation, craftsmen company management and on assisting customers in their choices.