## 2 Materials and Methods
### Prescriptive Method of RTQ-R  
The Quality Technical Regulation for the Energy Efficiency Level of Residential Buildings (RTQ-R) was published in September 2010 and is governed by Inmetro Ordinance number 18 of 16 January 2012 [22]. RTQ-R contains, as complementary documents, the Conformity Assessment Requirements for the Energy Efficiency of Buildings (Requisitos de Avaliacao da Conformidade para Efficiencia Energetica de Edificacoes--RAC) [25] and the manual for their application [26]. Membership is voluntary. The RTQ-R specifies technical methods and requirements for the classification of residential buildings according to the energy efficiency, allowing the labeling of single-family and multi-family buildings (weighted result of the evaluation of all autonomous HUs of the building), and common areas. For the HUs, the requirements regarding the thermal performance of the envelope, the water heating system, and possible subsidies (e.g., porosity of natural ventilation, rational water use, and ceiling reflectance) are evaluated in the RTQ-R. For common areas, factors including artificial lighting systems, elevators, centrifugal pumps, equipment, and water heating systems for baths, swimming pools, and saunas are considered in the RTQ-R. [PERSON] and [PERSON] [27] affirm that the use of solar thermal panels for heating water in the residential sector should be considered a significant sustainability practice. The RTQ-R evaluation method can be a prescriptive or performed by computer simulation. Based on the score obtained, the rating varies from A (more efficient) to E (less efficient), as shown in Table 3. This classification, together with other energy performance data, is documented in the ENCE provided to the evaluated property. The prescriptive method is applicable to most typologies constructed in the country and stimulates the application of architectural strategies appropriate to the bioclimatic zone (BZ); however, some practices can be evaluated only by simulation [28; 29], in addition to evaluating the skill of the professionals involved and the many data required [30; 31]. Therefore, [PERSON] and [PERSON] [32] emphasize the importance of professional practice being in harmony with the academy and affirm that the application of the RTQ-R not only allows the consumer to compare available properties but also favors the design of quality architectural projects, thus contributing to energy conservation. The RTQ-R [22] prescriptive method classifies the energy efficiency level of the HUs using an equation that gives the HU a total score for its efficiency level (ScoreHU); the score involves the \begin{table}
\begin{tabular}{c c c} \hline \hline
**Score** & **Efficiency Level** & **Corresponding Color in ENCE** \\ \hline Score \(\geq\) 4.5 & A & Green \\ \(3.5\leq\) Score \(<\) 4.5 & B & Light green \\ \(2.5\leq\) Score \(<\) 3.5 & C & Yellow \\ \(1.5\leq\) Score \(<\) 2.5 & D & Orange \\ Score \(<\) 1.5 & E & Red \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Efficiency level classification by score [32]. numerical equivalent of the envelope (EqNumEnv; thermal performance when the HU is naturally ventilated; the coefficient (a) corresponds to the BZ of the building, the numerical equivalent of the water heating system (EqNumAA), and the total points obtained with bonuses (Equation (1)). For BZ 8, the value of a is 0.65. \[\text{ScoreHU}=(\text{a}\times\text{EqNumEnv})+[(\text{1}-\text{a})\times\text{ EqNumAA}]+\text{Bonuses} \tag{1}\]  
Requirements related to the thermal transmittance, thermal capacity, solar absorbance, ventilation, and natural light must be respected, or the maximum rating will be 'C'. In the calculations developed in this study, an editable worksheet was used that was developed by the Laboratory of Energy Efficiency in Buildings (Laboratorio de Efficiencia Energetica em Edificacoes--LabEEE); the worksheet is available on the Catalogos [33]. The thermal performance of the envelope is obtained by the numerical equivalent of the naturally ventilated envelope (EqNumEnv).