PLEA 2008 – 25 th Conference on Passive and Low Energy Architecture, Dublin, 22 nd to 24 th October 2008 Thermal performance evaluation method for low cost single- family one-floor housing for Porto Alegre - Brazil Giane de Campos Grigoletti 1 *, Miguel Aloysio Sattler 2 Centro de Tecnologia, Universidade Federal de Santa Maria, Santa Maria, Brazil 1* grigoletti@smail.ufsm.br Escola de Engenharia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil 2 Abstract This paper presents a thermal performance evaluation method for low cost single-family one-floor housing considering the climatic conditions of Porto Alegre, city in the south of Brazil. The method aims toward a global evaluation of housing through requirements and criteria that complement the standards approved recently and it considers mathematical procedures that can be easily applied by government agents involved in this task. Thermal parameters such as global flow heat coefficients, thermal inertia, obtained from literature, are proposed. Four low cost houses built in Porto Alegre, considered to be references according to social and economic local reality, were evaluated through the method. Government agents involved in the project, design, financing, building, overseeing and evaluation of low cost housing in Porto Alegre and experts from research institutes in Brazil also gave their opinions of the method. Three degrees of performance for housing, in accordance with availability of government resources, are defined. The method can be used as an evaluation of possible solutions, thereby aiding decision makers. Keywords: hygrothermal performance; low cost housing; performance evaluation. 1. Introduction In Brazil the housing presents historically problems of thermal comfort and energetic efficiency. This is mainly verifiy for low cost housing and its low performance has been subject of broad researches. The studies found on the user's perception [1][2][3][4] or computational simulations and measurements in loco [5][6][7]. Studies have been developed with the intention of configuring guidelines for the project of low-income housing and define methods for evaluation for the Brazilian context [8][9][10]. In brief, the evaluations can be divided in three groups: measurements in loco evaluations; physical models evaluations (simulations computacionais or not); users' perception evaluations. The complexity of computational simulation methods is a difficulty for the improvement of low-income housing thermal performance. Because of the complexity, only experts in the thermal comfort are able to use the softwares, with the result that several buildings present inadequate thermal conditions mainly buildings for low and middle income families. The users’ perception evaluantin requer that housing have been constructed, that cannot be possible. Therefore, simplified methods could be a form of improving the quality of housing for the poors in Brazil. ABNT [8] recommends standard methods for thermal parameters, procedures for treatment of climatic data, general weather conditions for different regions, methods of evaluation and guidelines for low-income housing in Brazil. Also, ABNT specifies procedures for calculation of thermal resistance, thermal transmittance, thermal capacity, time-lag and solar factor for roofs and walls. Turik [9] proposes the use of coefficients of volumetric heat loss and heat load. Barbosa [10] proposes the comparison of thermal discomfort hours promoted by the housing with the thermal discomfort hours considered acceptable for a cultural referencial. All of the mentioned methods were developed for a partial evaluation of the building, considering isolated elements (walls and roof), except the method proposed by Turik [9] that considers the global coefficients. This paper presents some procedures based on simplified physical models for hygrothermal performance evaluation that intend to take the whole building behaviour into account. Besides the global coefficients, the thermal inertia, the thermal effusivity and the radiant temperaturae asymmetry are considered. The procedures can be used in the design phase. Proposed thermal parameters are aplicable to Brazilian reality and to low cost housing. The parameters were obtained from specialized bibliography and submitted to the appreciation of seven government agents and six experts on thermal comfort field.