Determining the U-Value of Façades Using the Thermometric Method: Potentials and Limitations

energies Article Determining the U-Value of Façades Using the Thermometric Method: Potentials and Limitations David Bienvenido-Huertas 1,*ID , Roberto Rodríguez-Álvaro 2ID , Juan JoséMoyano 1ID , Fernando Rico 1ID and David Marín1ID 1Department of Graphical Expression and Building Engineering, University of Seville, 41012 Seville, Spain; [email protected] (J.J.M.); [email protected] (F.R.); [email protected] (D.M.) 2Department of Civil Engineering, Universidade da Coruña, 15071 A Coruña, Spain; roberto.r[email protected] *Correspondence: [email protected] Received: 26 December 2017; Accepted: 1 February 2018; Published: 3 February 2018 Abstract: The thermal transmittance of building envelopes determines to a large extent the energy demand of buildings. Thus, there is a keen interest in having methods which can precisely evaluate thermal transmittance. From a scientific point of view, this study analyses the viability of the application of the thermometric method (THM), one of the most used methods in Spain. For this purpose, the test method has been improved by determining the adequate test conditions, the selection and installation of equipment, data acquisition and post-processing, and the estimation of uncertainty. We analyse eight case studies in a Mediterranean climate (Csa) to determine the potentials and limitations of the method. The results show that the values obtained through THM are valid under winter environmental conditions with relative uncertainties between 6% and 13%, while difficulties to perform the test in optimal conditions, and therefore to obtain valid results in warmer seasons, are detected. In this regard, the case studies which obtained a greater number of observations by performing the filtrate conditions were able to obtain representative results. Furthermore, there are significant differences depending on the kind of equipment and probes used during the experimental campaign. Finally, in warm climate regions a data filtrate can be considered for observations of a temperature difference higher than 5 ◦ C, obtaining valid results for the case studies, although the rise in the thermal gradient can guarantee a greater stability of data. Keywords: thermal transmittance (U-value); thermometric method (THM); façades; internal convective coefficient; in situ measurement 1. Introduction The concern about the environmental degradation of the planet has increased over the past few years. The building sector is among those most responsible for this phenomenon because of the amount of energy that it consumes [1]. In Europe, 24.79% of the total energy used in 2014 was attributed to residential buildings [ 2 ]. Likewise, the energy consumption has shown a tendency to increase 1% per year since 1990, so a higher energy consumption is expected [ 3 ]. In the case of the region of Andalusia (Spain), the residential building sector was responsible for 15.9% of the total energy consumption in 2016, which represents an increase of 4.1% in comparison with 2014 [ 4 ]. In this regard, it is important to highlight that the main source of consumption is attributed to meeting the heating demand [5–7]. Due to the fact that most of the energy consumed during the use phase of residential buildings comes from non-renewable resources, it is necessary to reduce the energy consumption in the existing building stock. Thus, the reduction of the energy demand and carbon dioxide emissions is the top priority objective of the building sector. Energies 2018,11, 360; doi:10.3390/en11020360 www.mdpi.com/journal/energies Energies 2018,11, 360 2 of 17 This improvement in energy behaviour must be made in existing buildings. Most of Spain’s building stock was built after the Spanish Civil War [ 8 ]. In this sense, as stated by Kurtz et al. [ 9 ], the thermal transmittance values of those buildings walls are higher than the limit values set by the Spanish Technical Building Code [ 10 ]. Furthermore, façades are the building envelope elements which most contribute to energy losses [ 11 – 14 ]. In this regard, Moyano Campos et al. [ 11 ] established that the analysed façades exceeded more of 100% the maximum acceptable value of the energy loss set by Spanish regulations, and that this situation could be solved by incorporating more insulation. Thus, an improvement proposal regarding the thermal behaviour of external building walls represents one of the main performances in passive protection buildings [ 15 ]. Different procedures such as energy audits and checking the adequacy of safety and maintenance measures in buildings are fundamental to the study of building energy performances as well as to the proposal of energy conservation measures (ECMs) for building façades [16]. Thermal transmittance (also known as U-value) is one of the most significant properties which define the energy behaviour of a building envelope. The U-value is understood as the amount of heat which flows through a certain element per unit area and time. This property can traditionally be determined by means of different procedures such as estimated methods [ 17 ] or in situ tests (the heat flow meter method) [ 18 ], or quantitative methods such as infrared thermography [ 19 – 23 ]). These methods have been widely studied in the literature and there are several studies in which the validity of their use is compared [24–27]. However, one of the most-used methods in Spain is called the thermometric method (THM) by the authors of this paper, and it is used by different trademarks. Most professionals use this method in order to perform energy audits. It can also be employed by authorised laboratories in the country [ 28 , 29 ]. However, there are no standards to develop the method, apart from specifications provided by the equipment’s manufacturers [ 30 , 31 ]. After a review of the literature, it was verified that there are no studies in which the viability of THM is analysed. This method is characterised by the measurement of indoor and outdoor air temperatures as well as the internal surface temperature of the wall, but the heat flux is not measured. It is a method with simple theoretical and metrology fundamentals. These simplicities can lead to the fact that the obtained thermal transmittance value can be non-representative. In this context, Ficco et al. [ 25 ] indicated that in situ measurements with a simple theoretical development may face metrological problems, which can lead to atypical values with significant percentages of relative uncertainty. However, THM shows a priori some advantages due to the fact that not using a heat flux plate allows the tests to be performed more easily and avoids the disturbance of the thermal behaviour of the wall caused by using the plate. According to this, Trethowen [ 32 ], Desogus et al. [ 33 ], and Cesaratto et al. [ 34 ] established that the presence of the heat flux plate could cause a disruption in the heat flux, consequently influencing the measurement result. Another important aspect to highlight is the reduction of the error achieved by avoiding the use of a heat flux plate. Peng and Wu [ 35 ] demonstrated that the main contribution to error in the thermal transmittance results is due to the heat flux measurement. Cucumo et al. [ 36 ] indicated that the location of the plate has an influence on the correct heat flux measurement. In this sense, Meng et al. [ 37 ] established that the maximum error of the U-value due to the use of thermocouples can be up to 6%, while that caused by the use of a heat flux plate can reach up to 26%. Therefore, this research aimed to develop THM by establishing the best test conditions as well as the guidelines of the qualitative analysis of the wall, the installation of the equipment, data post-processing, and the estimation of uncertainty. The method is applied to eight study cases of heavy walls, and the results are compared to the estimated value of thermal transmittance according to ISO 6496 with the conductivity correction factors established by Pérez-Bella et al. [ 38 ] for the study areas. Energies 2018,11, 360 3 of 17 2. Theory THM is a development of the average method set in ISO 9869-1 [ 18 ]. It is based on the instantaneous measurement of the heat flow as well as the indoor and outdoor air temperatures under the conditions of a stationary regime: U=q Tin −Tout W m2·K(1) where q (W/m 2 ) is the heat flux of the wall, Tin (K) is the internal air temperature, and Tout (K) is the external air temperature. Using Newton’s Law of Cooling, the heat transfer per unit surface could be determined by the following expression: q=hin(Tin −Ts,in)W m2(2) where hin (W/(m 2· K)) is the internal convective coefficient and Ts,in (K) is the internal surface temperature of the wall. From Equations (1) and (2), the equation used in THM is obtained: U=hin(Tin −Ts,in) (Tin −Tout)W m2·K(3) It is important to highlight that this method always uses a fixed value of the internal convective coefficient, based on the value of the internal surface thermal resistance set in ISO 6946. Taking into account that the surface resistance is the reciprocal of the convective coefficient (Equation (4)) and the tabulated value of Rs,in set by ISO 6946 for a vertical building envelope is 0.13 ((m 2· K)/W), we obtain the equation of THM for the U-value measurement of façades (Equation (5)). Rs,in =1 hin (4) U=7.69(Tin −Ts,in) (Tin −Tout)W m2·K(5) The fundamental difference between Equations (1) and (5) is in the numerator of the equations: in Equation (1) it is necessary to measure the heat flux of the wall, so the result is subject to a possible disruption of the heat flux due to the use of the plate [ 32 – 34 ] and has a high level of uncertainty associated with its location [ 35 – 37 ], while in Equation (5) the necessary variable measurement is only carried out by temperature probes, reducing the error associated with the probes’ location. The temperature data are obtained by thermocouples, which measure both the exterior and interior environmental temperatures as well as the internal surface temperature of the wall [30,31]. Some manufacturers’ specifications in relation to the installation of the equipment and test durations are listed below [31]: • Mounting the interior and exterior environmental temperature probes 30 cm away from the wall as well as at the same height as the internal surface temperature probes. •No direct solar radiation. •Measurements should be carried out during the night. Moreover, it is advisable to have a significant difference between the internal and external temperatures, preferably higher than 15 ◦C. Some of these specifications coincide with those set in ISO 9869-1. Requirements such as avoiding direct solar radiation on the façades and performing the test during the night are indicated in the standard, although the performance of the test during the night is established for light walls, while for heavy walls it should be longer. Energies 2018,11, 360 4 of 17 However, these specifications are limited to ensure that the test is performed under correct metrological guidelines. Furthermore, the internal convective coefficient is utilised during the building design process to determine the energy behaviour, which overestimates the thermal transmittance [ 21 , 23 ], so the results obtained may not correspond to the actual values. 3. Quality Control, Data Post-Processing, and Uncertainty Quantification of the Method Due to the fact that the metrological requirements given by the manufacturer do not address all factors that may affect the results of the test, we suggest some guidelines and criteria that should be applied when performing a THM test. 3.1. Test Conditions In order to avoid direct solar radiation, the façade should preferably face north. Furthermore, the test should be conducted on walls without anomalies or pathologies, such as moisture or damage and defects. Likewise, the manufacturers recommend a temperature difference higher than 15 ◦ C [ 30 , 31 ]. In addition, the ideal test conditions will be those with no rainfall and a wind speed lower than 1 m/s. In this respect, the effects of these climatological variables can last from 2 to 6 h after these climate events disappear [23]. Before performing the test, it is advisable to evaluate the possible presence of non-homogeneities and thermal bridges in the wall through infrared thermography. This assessment should be carried out from both the internal and external sides of the wall by analysing them using ISO 6781 [ 39 ], as well as considering the following aspects: • For at least 24 h before starting the test, the external air temperature must not vary more than ±10 ◦C from the existing temperature at the moment of starting the inspection. • During the inspection, the outdoor air temperature must not vary more than ± 5 ◦ C and the indoor air temperature should vary no more than ±2◦C with respect to their initial values. • Taking an infrared thermal image should be avoided in these three cases: when it is detected that the wall surface is not dry, if it is raining at the moment of performing the test, or if the wind speed is higher than 8 m/s. 3.2. Selecting and Installing the Equipment In order to perform the test, a data logger and temperature probes are required. Moreover, it is advisable to mount a weather station near the wall in order to measure the external environmental conditions. Likewise, an IR camera is also required to apply ISO 6781. Thermocouples should be as indicated by IEC 60584-1 [ 40 ]. There are different kinds of thermocouples , so we recommend a class-1 grade thermocouple due its tolerances and specifications. In terms of the data logger, it is also preferable to use programmable equipment which allow one to make data records with flexible periods from 1 s to 900 s. Before performing the test, the equipment and probes should be correctly calibrated. Criteria for installing the equipment are as follows: • Thermocouples measuring the internal surface temperature should be mounted with a space of 10 cm between them, as well as 20 mm away from the mortar joints of the pieces of brick of the internal side of the wall [ 31 , 37 ] at a height of 1.5 m above the floor [ 19 ]. The test described in ISO 6781 may be useful to determine the position of the mortar joints. According to the indications of Meng et al. [ 37 ], when the mortar joints cannot be determined, probes must be mounted without being vertically or horizontally aligned. A fixed mastic can also be used to achieve good contact with the wall [ 31 ]. In addition, it is important to avoid mounting the sensors in the corners, since the temperature is usually higher there than in the rest of the wall [23]. Energies 2018,11, 360 5 of 17 • Moreover, the internal and external air temperature sensors should be placed as horizontally aligned as possible, at a distance of 30 cm from the wall in order to avoid convective effects [31]. • In the case of those devices which directly measure air temperature, they should be placed at a distance of 30 cm from the internal side of the wall to prevent being affected by convective effects, with a height difference of 20 cm from the rest of the probes to avoid significant differences in temperature measurement. • The weather station should be installed as near as possible to the wall under study, avoiding its installation towards other orientations. 3.3. Data Acquisition and Post-Processing The test duration will depend on the typology of the wall to be analysed as well as the heat flow meter method: for light walls, the test should be carried out during the night to avoid direct solar radiation, while for heavy walls, it should last between 72 and 168 h [ 18 ]. The use of a data logger that records data for a period between 1 and 900 s will allow the variation of the frequency of data acquisition used in each test. By analysing the literature, the use of different sampling periods for the heat flow meter method and the quantitative methods of infrared thermography were detected: 2 min [ 41 ], 5 min [ 23 , 24 , 33 ], 15 min [ 19 , 25 ], 30 min [ 25 ], 60 min [ 25 ], or 90 min [ 25 ]. In this regard, we propose the use of sampling times of 15 min, which make the subsequent data analysis easier. With respect to data post-processing, we recommend the use of a statistical programming language like R [ 42 ] due to its versatility when aggregating, validating, analysing, and reporting the obtained data. The generated dataset should be filtered by those observations with a high temperature gradient. This differential should be of 15 ◦ C, although in those regions where the external environmental conditions make that requirement impossible, the use of a minor differential temperature should be considered. Likewise, only records obtained without precipitation and with a wind speed lower than 1 m/s should be considered. The result obtained through the method is determined by the average value of the filtered subset of nvalues of thermal transmittance: U=1 n n ∑ i=1 UiW m2·K(6) where Ui (W/(m 2· K)) is the U-value obtained from Equation (5) for a certain observation i , and n is the total number of filtered observations of the dataset. To determine the validity of the U-value, the criterion proposed in ISO 9869-1 should be used. The valid results will be those with a difference less than 20% between the estimated value in ISO 6946 [17] and the value measured on site (see Equation (7)). σ=UTHM −UEstimated UEstimated [%](7) The estimated value is obtained from ISO 6946 as follows: UEstimated =1 Rs,in +∑si/λi+Rs,out W m2·K(8) where λi (W/(m · K)) and si (m) are the thermal conductivity and the thickness of each of the layers of the wall, respectively, and Rs,in and Rs,out ((m 2· K)/W) are the internal and external surface resistances. These last two variables are obtained by means of the tabulated values in the standard ISO 6946. One of the estimation method’s aspects which most affect the determination of the representative values is the existing difference between the used value of thermal conductivity and the actual value of each layer. This difference arises to the fact that in most existing databases, such as the constructive elements catalogue of the Spanish Technical Building Code in Spain [ 43 ], fixed environmental Energies 2018,11, 360 6 of 17 values are used in order to calculate the thermal properties according to ISO 10456 [ 44 ]. However, Pérez-Bella et al. [ 38 ] proposed the use of conductivity correction factors (CCF) for the conductivity values as a simplified procedure provided by ISO 10456 for all the Spanish cities, as it can be seen in the following expression: λCCF =λ·CCFW m·K(9) where CCF (dimensionless) is the conductivity correction factor assigned to the municipality where the wall is located [38]. In order to determine the thickness of façade layers, a comparison with other buildings built during the same period as well as available design data and endoscopies can be used [18,25]. 3.4. Estimating the Uncertainty The uncertainty associated with THM is estimated by the combined standard uncertainty. The uncertainty contributions related to the measurement are due to the accuracy of the equipment employed (this accuracy is indicated in the manufacturers’ technical specifications) as well as the operative conditions associated with the performance of the test and the ambient conditions (see Table 1). Table 1. Uncertainty contributions estimated by the method. Type Description Estimation Measurement equipment and procedure Thermocouples in poor contact with the surface 1–5% a Non-uniformity of temperature due to heterogeneities in the wall or impacts of internal/external radiation 1–5% b Installation of thermocouples near to the mortar joints of the pieces of brick of the internal side of the wall 2–6% c Thermocouple linearity and sensitivity 0.1–0.2 ◦Cb A/D converter resolution and data transmission 1–2% b Environment Temperature instability due to environmental climatic variations 3–10% a Influence of external and internal radiation from the sun or lighting equipment 1–2% b Influence of high speed wind 1–2% Influence of moisture in measurements (i.e., moisture condensation) 1–2% b a Estimated value according to ISO 9869-1 [ 18 ]; b Estimated value according to Ficco et al. [ 25 ]; c Estimated value according to Meng et al. [37]. Basing on the mathematical model of THM (Equation (5)), uncertainty contributions for the variables Tin , Tout , and Ts,in are set. Due to the fact that hin (7.69) is a non-measured value, it has no contributions from uncertainty sources. In order to estimate the combined standard uncertainty, ISO/IEC Guide 98-3:2008 [ 45 ] is used. According to this standard, the uncertainty for input quantities which are uncorrelated, as in the THM method, are determined by the following equation: uc(y)=v u u t n ∑ i=1δf δxi2 u2(xi)(10) where δf δxiare the sensitivity coefficients and u(xi)are the uncertainty contributions. As mentioned above, the sources of uncertainty are associated with three of the four variables, so there will be a total of three sensitivity coefficients. These sensitivity coefficients are partial derivatives from Equation (5) regarding the input variables Tin , Tout , and Ts,in , which are used to describe how the output estimate changes according to the variations in these variables: Energies 2018,11, 360 7 of 17 c1=δU δTin =−hin(Tout−Ts,in) (Tin−Tout)2=−7.69(Tout−Ts,in) (Tin−Tout)2 c2=δU δTout =−hin Tin−Tout =−7.69 Tin−Tout c3=δU δTs,in =hin(Tin−Ts,in) (Tin−Tout)2=7.69(Tin−Ts,in) (Tin−Tout)2 (11) 4. Experimental Campaign In order to validate the method, eight walls from different building periods were monitored (see Figure 1). These façades are located in the city of Seville (case studies 1–6) and Cadiz (case studies 7–8) (see Table 2). They represent typical façade configurations found in these areas. In such cities, the climate is classified by Köppen and Geiger as Csa [46]: mild winters and hot summers. Energies 2018, 11, x FOR PEER REVIEW 7 of 18 =󰇧 ,󰇨=ℎ−, (−)=7.69−, (−) 4. Experimental Campaign In order to validate the method, eight walls from different building periods were monitored (see Figure 1). These façades are located in the city of Seville (case studies 1–6) and Cadiz (case studies 7–8) (see Table 2). They represent typical façade configurations found in these areas. In such cities, the climate is classified by Köppen and Geiger as Csa [46]: mild winters and hot summers. Figure 1. Façades of some of the analysed buildings: (a) C-5 (1966), (b) C-6 (1981), and (c) C-7 (2004). The procedures described in Section 3 of this paper were applied to all walls (see Figure 2). The tests were conducted in winter (C-1, C-2, and C-3), summer (C-4, C-5, C-6, and C-7), and autumn (C-8). The duration of the tests was 72 h in all case studies and the equipment were configured with a sampling frequency of 15 min. To carry out the tests, two data loggers with different probes were used (see Table 3) in order to determine possible existing deviations. Figure 2. (a) Installation of the equipment and (b) internal qualitative assessment by means of infrared thermography. Design data of all case studies were obtained, so their compositions were determined by this source and the transmittance values were estimated by standard ISO 6946 (see Table 2). Figure 1. Façades of some of the analysed buildings: (a) C-5 (1966), (b) C-6 (1981), and (c) C-7 (2004). The procedures described in Section 3of this paper were applied to all walls (see Figure 2). The tests were conducted in winter (C-1, C-2, and C-3), summer (C-4, C-5, C-6, and C-7), and autumn (C-8). The duration of the tests was 72 h in all case studies and the equipment were configured with a sampling frequency of 15 min. To carry out the tests, two data loggers with different probes were used (see Table 3) in order to determine possible existing deviations. Energies 2018, 11, x FOR PEER REVIEW 7 of 18 =󰇧 ,󰇨=ℎ−, (−)=7.69−, (−) 4. Experimental Campaign In order to validate the method, eight walls from different building periods were monitored (see Figure 1). These façades are located in the city of Seville (case studies 1–6) and Cadiz (case studies 7–8) (see Table 2). They represent typical façade configurations found in these areas. In such cities, the climate is classified by Köppen and Geiger as Csa [46]: mild winters and hot summers. Figure 1. Façades of some of the analysed buildings: (a) C-5 (1966), (b) C-6 (1981), and (c) C-7 (2004). The procedures described in Section 3 of this paper were applied to all walls (see Figure 2). The tests were conducted in winter (C-1, C-2, and C-3), summer (C-4, C-5, C-6, and C-7), and autumn (C-8). The duration of the tests was 72 h in all case studies and the equipment were configured with a sampling frequency of 15 min. To carry out the tests, two data loggers with different probes were used (see Table 3) in order to determine possible existing deviations. Figure 2. (a) Installation of the equipment and (b) internal qualitative assessment by means of infrared thermography. Design data of all case studies were obtained, so their compositions were determined by this source and the transmittance values were estimated by standard ISO 6946 (see Table 2). Figure 2. ( a ) Installation of the equipment and ( b ) internal qualitative assessment by means of infrared thermography. Design data of all case studies were obtained, so their compositions were determined by this source and the transmittance values were estimated by standard ISO 6946 (see Table 2). Energies 2018,11, 360 8 of 17 Table 2. Technical characteristics and thermophysical properties of case studies 1–8. # Component C-1 s(mm) λ(W/(m·K)) aR((m2·K)/W) Sketch 1 Cement mortar 15 1.30 - Energies 2018, 11, x FOR PEER REVIEW 8 of 18 Table 2. Technical characteristics and thermophysical properties of case studies 1–8. # Component C-1 s (mm) λ (W/(m·K)) a R ((m 2 ·K)/W) Sketch 1 Cement mortar 15 1.30 - 2 Perforated brick 115 0.35 - 3 Cement mortar 10 1.30 - 4 Air gap 20 - 0.17 c 5 Hollow brick 50 0.32 - 6 Gypsum plaster 15 0.57 - , = 0.13 (m 2 ·K)/W b , = 0.04 (m 2 ·K)/W b  = 1.0385 d # Component C-2 s (mm) λ (W/(m·K)) a R ((m 2 ·K)/W) Sketch 1 Cement mortar 15 1.30 - 2 Perforated brick 115 0.35 - 3 Cement mortar 10 1.30 - 4 Extruded polystyrene (XPS) insulation 35 0.036 - 5 Air gap 10 - 0.15 c 6 Hollow brick 50 0.32 - 7 Gypsum plaster 15 0.57 - , = 0.13 (m 2 ·K)/W b , = 0.04 (m 2 ·K)/W b  = 1.0385 d # Component C-3 s (mm) λ (W/(m·K)) a R ((m 2 ·K)/W) Sketch 1 Cement mortar 15 1.30 - 2 Solid brick 115 0.85 - 3 Cement mortar 10 1.30 - 4 Air gap 100 - 0.18 c 5 Hollow brick 50 0.32 - 6 Cement mortar 15 1.30 - 7 Ceramic tiles 10 1.30 - , = 0.13 (m 2 ·K)/W b , = 0.04 (m 2 ·K)/W b  = 1.0385 d # Component C-4 s (mm) λ (W/(m·K)) a R((m 2 ·K)/W) Sketch 1 Perforated brick 115 0.35 - 2 Cement mortar 15 1.30 - 3 Extruded polystyrene (XPS) insulation 30 0.036 - 4 Air gap 70 - 0.18 c 5 Hollow brick 70 0.32 - 6 Gypsum plaster 15 0.57 - , = 0.13 (m 2 ·K)/W b , = 0.04 (m 2 ·K)/W b  = 1.0385 d # Component C-5 s (mm) λ (W/(m·K)) a R ((m 2 ·K)/W) Sketch 1 Perforated brick 115 0.35 - 2 Cement mortar 10 1.30 - 3 Air gap 100 - 0.18 c 4 Hollow brick 70 0.32 - 5 Gypsum plaster 15 0.57 - ,=0.13 (m 2 ·K)/W b ,=0.04 (m 2 ·K)/W b  = 1.0385 d # Component C-6 s (mm) λ (W/(m·K)) a R ((m 2 ·K)/W) Sketch 1 Cement mortar 20 1.30 - 2 Perforated brick 115 0.35 - 3 Cement mortar 10 1.30 - 4 Mineral wool (MW) insulation 20 0.05 - 5 Air gap 50 - 0.18 c 6 Hollow brick 70 0.32 - 7 Gypsum plaster 15 0.57 - , = 0.13 (m 2 ·K)/W b , = 0.04 (m 2 ·K)/W b  = 1.0385 d # Component C-7 s (mm) λ (W/(m·K)) a R ((m 2 ·K)/W) Sketch 1 Cement mortar 25 1.30 - 2 Perforated brick 115 0.35 - 3 Cement mortar 10 1.30 - 4 Polyurethane (PUR) insulation 40 0.028 - 5 Air gap 100 - 0.18 c 6 Hollow brick 40 0.32 - 2 Perforated brick 115 0.35 - 3 Cement mortar 10 1.30 - 4 Air gap 20 - 0.17 c 5 Hollow brick 50 0.32 - 6 Gypsum plaster 15 0.57 - Rs,in = 0.13 (m2·K)/W bRs,out = 0.04 (m2·K)/W bCCF = 1.0385 d # Component C-2 s(mm) λ(W/(m·K)) aR((m2·K)/W) Sketch 1 Cement mortar 15 1.30 - Energies 2018, 11, x FOR PEER REVIEW 8 of 18 Table 2. Technical characteristics and thermophysical properties of case studies 1–8. # Component C-1 s (mm) λ (W/(m·K)) a R ((m 2 ·K)/W) Sketch 1 Cement mortar 15 1.30 - 2 Perforated brick 115 0.35 - 3 Cement mortar 10 1.30 - 4 Air gap 20 - 0.17 c 5 Hollow brick 50 0.32 - 6 Gypsum plaster 15 0.57 - , = 0.13 (m 2 ·K)/W b , = 0.04 (m 2 ·K)/W b  = 1.0385 d # Component C-2 s (mm) λ (W/(m·K)) a R ((m 2 ·K)/W) Sketch 1 Cement mortar 15 1.30 - 2 Perforated brick 115 0.35 - 3 Cement mortar 10 1.30 - 4 Extruded polystyrene (XPS) insulation 35 0.036 - 5 Air gap 10 - 0.15 c 6 Hollow brick 50 0.32 - 7 Gypsum plaster 15 0.57 - , = 0.13 (m 2 ·K)/W b , = 0.04 (m 2 ·K)/W b  = 1.0385 d # Component C-3 s (mm) λ (W/(m·K)) a R ((m 2 ·K)/W) Sketch 1 Cement mortar 15 1.30 - 2 Solid brick 115 0.85 - 3 Cement mortar 10 1.30 - 4 Air gap 100 - 0.18 c 5 Hollow brick 50 0.32 - 6 Cement mortar 15 1.30 - 7 Ceramic tiles 10 1.30 - , = 0.13 (m 2 ·K)/W b , = 0.04 (m 2 ·K)/W b  = 1.0385 d # Component C-4 s (mm) λ (W/(m·K)) a R((m 2 ·K)/W) Sketch 1 Perforated brick 115 0.35 - 2 Cement mortar 15 1.30 - 3 Extruded polystyrene (XPS) insulation 30 0.036 - 4 Air gap 70 - 0.18 c 5 Hollow brick 70 0.32 - 6 Gypsum plaster 15 0.57 - , = 0.13 (m 2 ·K)/W b , = 0.04 (m 2 ·K)/W b  = 1.0385 d # Component C-5 s (mm) λ (W/(m·K)) a R ((m 2 ·K)/W) Sketch 1 Perforated brick 115 0.35 - 2 Cement mortar 10 1.30 - 3 Air gap 100 - 0.18 c 4 Hollow brick 70 0.32 - 5 Gypsum plaster 15 0.57 - ,=0.13 (m 2 ·K)/W b ,=0.04 (m 2 ·K)/W b  = 1.0385 d # Component C-6 s (mm) λ (W/(m·K)) a R ((m 2 ·K)/W) Sketch 1 Cement mortar 20 1.30 - 2 Perforated brick 115 0.35 - 3 Cement mortar 10 1.30 - 4 Mineral wool (MW) insulation 20 0.05 - 5 Air gap 50 - 0.18 c 6 Hollow brick 70 0.32 - 7 Gypsum plaster 15 0.57 - , = 0.13 (m 2 ·K)/W b , = 0.04 (m 2 ·K)/W b  = 1.0385 d # Component C-7 s (mm) λ (W/(m·K)) a R ((m 2 ·K)/W) Sketch 1 Cement mortar 25 1.30 - 2 Perforated brick 115 0.35 - 3 Cement mortar 10 1.30 - 4 Polyurethane (PUR) insulation 40 0.028 - 5 Air gap 100 - 0.18 c 6 Hollow brick 40 0.32 - 2 Perforated brick 115 0.35 - 3 Cement mortar 10 1.30 - 4Extruded polystyrene (XPS) insulation 35 0.036 - 5 Air gap 10 - 0.15 c 6 Hollow brick 50 0.32 - 7 Gypsum plaster 15 0.57 - Rs,in = 0.13 (m2·K)/W bRs,out = 0.04 (m2·K)/W bCCF = 1.0385 d # Component C-3 s(mm) λ(W/(m·K)) aR((m2·K)/W) Sketch 1 Cement mortar 15 1.30 - Energies 2018, 11, x FOR PEER REVIEW 8 of 18 Table 2. Technical characteristics and thermophysical properties of case studies 1–8. # Component C-1 s (mm) λ (W/(m·K)) a R ((m 2 ·K)/W) Sketch 1 Cement mortar 15 1.30 - 2 Perforated brick 115 0.35 - 3 Cement mortar 10 1.30 - 4 Air gap 20 - 0.17 c 5 Hollow brick 50 0.32 - 6 Gypsum plaster 15 0.57 - , = 0.13 (m 2 ·K)/W b , = 0.04 (m 2 ·K)/W b  = 1.0385 d # Component C-2 s (mm) λ (W/(m·K)) a R ((m 2 ·K)/W) Sketch 1 Cement mortar 15 1.30 - 2 Perforated brick 115 0.35 - 3 Cement mortar 10 1.30 - 4 Extruded polystyrene (XPS) insulation 35 0.036 - 5 Air gap 10 - 0.15 c 6 Hollow brick 50 0.32 - 7 Gypsum plaster 15 0.57 - , = 0.13 (m 2 ·K)/W b , = 0.04 (m 2 ·K)/W b  = 1.0385 d # Component C-3 s (mm) λ (W/(m·K)) a R ((m 2 ·K)/W) Sketch 1 Cement mortar 15 1.30 - 2 Solid brick 115 0.85 - 3 Cement mortar 10 1.30 - 4 Air gap 100 - 0.18 c 5 Hollow brick 50 0.32 - 6 Cement mortar 15 1.30 - 7 Ceramic tiles 10 1.30 - , = 0.13 (m 2 ·K)/W b , = 0.04 (m 2 ·K)/W b  = 1.0385 d # Component C-4 s (mm) λ (W/(m·K)) a R((m 2 ·K)/W) Sketch 1 Perforated brick 115 0.35 - 2 Cement mortar 15 1.30 - 3 Extruded polystyrene (XPS) insulation 30 0.036 - 4 Air gap 70 - 0.18 c 5 Hollow brick 70 0.32 - 6 Gypsum plaster 15 0.57 - , = 0.13 (m 2 ·K)/W b , = 0.04 (m 2 ·K)/W b  = 1.0385 d # Component C-5 s (mm) λ (W/(m·K)) a R ((m 2 ·K)/W) Sketch 1 Perforated brick 115 0.35 - 2 Cement mortar 10 1.30 - 3 Air gap 100 - 0.18 c 4 Hollow brick 70 0.32 - 5 Gypsum plaster 15 0.57 - ,=0.13 (m 2 ·K)/W b ,=0.04 (m 2 ·K)/W b  = 1.0385 d # Component C-6 s (mm) λ (W/(m·K)) a R ((m 2 ·K)/W) Sketch 1 Cement mortar 20 1.30 - 2 Perforated brick 115 0.35 - 3 Cement mortar 10 1.30 - 4 Mineral wool (MW) insulation 20 0.05 - 5 Air gap 50 - 0.18 c 6 Hollow brick 70 0.32 - 7 Gypsum plaster 15 0.57 - , = 0.13 (m 2 ·K)/W b , = 0.04 (m 2 ·K)/W b  = 1.0385 d # Component C-7 s (mm) λ (W/(m·K)) a R ((m 2 ·K)/W) Sketch 1 Cement mortar 25 1.30 - 2 Perforated brick 115 0.35 - 3 Cement mortar 10 1.30 - 4 Polyurethane (PUR) insulation 40 0.028 - 5 Air gap 100 - 0.18 c 6 Hollow brick 40 0.32 - 2 Solid brick 115 0.85 - 3 Cement mortar 10 1.30 - 4 Air gap 100 - 0.18 c 5 Hollow brick 50 0.32 - 6 Cement mortar 15 1.30 - 7 Ceramic tiles 10 1.30 - Rs,in = 0.13 (m2·K)/W bRs,out = 0.04 (m2·K)/W bCCF = 1.0385 d # Component C-4 s(mm) λ(W/(m·K)) aR((m2·K)/W) Sketch 1 Perforated brick 115 0.35 - Energies 2018, 11, x FOR PEER REVIEW 8 of 18 Table 2. Technical characteristics and thermophysical properties of case studies 1–8. # Component C-1 s (mm) λ (W/(m·K)) a R ((m 2 ·K)/W) Sketch 1 Cement mortar 15 1.30 - 2 Perforated brick 115 0.35 - 3 Cement mortar 10 1.30 - 4 Air gap 20 - 0.17 c 5 Hollow brick 50 0.32 - 6 Gypsum plaster 15 0.57 - , = 0.13 (m 2 ·K)/W b , = 0.04 (m 2 ·K)/W b  = 1.0385 d # Component C-2 s (mm) λ (W/(m·K)) a R ((m 2 ·K)/W) Sketch 1 Cement mortar 15 1.30 - 2 Perforated brick 115 0.35 - 3 Cement mortar 10 1.30 - 4 Extruded polystyrene (XPS) insulation 35 0.036 - 5 Air gap 10 - 0.15 c 6 Hollow brick 50 0.32 - 7 Gypsum plaster 15 0.57 - , = 0.13 (m 2 ·K)/W b , = 0.04 (m 2 ·K)/W b  = 1.0385 d # Component C-3 s (mm) λ (W/(m·K)) a R ((m 2 ·K)/W) Sketch 1 Cement mortar 15 1.30 - 2 Solid brick 115 0.85 - 3 Cement mortar 10 1.30 - 4 Air gap 100 - 0.18 c 5 Hollow brick 50 0.32 - 6 Cement mortar 15 1.30 - 7 Ceramic tiles 10 1.30 - , = 0.13 (m 2 ·K)/W b , = 0.04 (m 2 ·K)/W b  = 1.0385 d # Component C-4 s (mm) λ (W/(m·K)) a R((m 2 ·K)/W) Sketch 1 Perforated brick 115 0.35 - 2 Cement mortar 15 1.30 - 3 Extruded polystyrene (XPS) insulation 30 0.036 - 4 Air gap 70 - 0.18 c 5 Hollow brick 70 0.32 - 6 Gypsum plaster 15 0.57 - , = 0.13 (m 2 ·K)/W b , = 0.04 (m 2 ·K)/W b  = 1.0385 d # Component C-5 s (mm) λ (W/(m·K)) a R ((m 2 ·K)/W) Sketch 1 Perforated brick 115 0.35 - 2 Cement mortar 10 1.30 - 3 Air gap 100 - 0.18 c 4 Hollow brick 70 0.32 - 5 Gypsum plaster 15 0.57 - ,=0.13 (m 2 ·K)/W b ,=0.04 (m 2 ·K)/W b  = 1.0385 d # Component C-6 s (mm) λ (W/(m·K)) a R ((m 2 ·K)/W) Sketch 1 Cement mortar 20 1.30 - 2 Perforated brick 115 0.35 - 3 Cement mortar 10 1.30 - 4 Mineral wool (MW) insulation 20 0.05 - 5 Air gap 50 - 0.18 c 6 Hollow brick 70 0.32 - 7 Gypsum plaster 15 0.57 - , = 0.13 (m 2 ·K)/W b , = 0.04 (m 2 ·K)/W b  = 1.0385 d # Component C-7 s (mm) λ (W/(m·K)) a R ((m 2 ·K)/W) Sketch 1 Cement mortar 25 1.30 - 2 Perforated brick 115 0.35 - 3 Cement mortar 10 1.30 - 4 Polyurethane (PUR) insulation 40 0.028 - 5 Air gap 100 - 0.18 c 6 Hollow brick 40 0.32 - 2 Cement mortar 15 1.30 - 3Extruded polystyrene (XPS) insulation 30 0.036 - 4 Air gap 70 - 0.18 c 5 Hollow brick 70 0.32 - 6 Gypsum plaster 15 0.57 - Rs,in = 0.13 (m2·K)/W bRs,out = 0.04 (m2·K)/W bCCF = 1.0385 d # Component C-5 s(mm) λ(W/(m·K)) aR((m2·K)/W) Sketch 1 Perforated brick 115 0.35 - Energies 2018, 11, x FOR PEER REVIEW 8 of 18 Table 2. Technical characteristics and thermophysical properties of case studies 1–8. # Component C-1 s (mm) λ (W/(m·K)) a R ((m 2 ·K)/W) Sketch 1 Cement mortar 15 1.30 - 2 Perforated brick 115 0.35 - 3 Cement mortar 10 1.30 - 4 Air gap 20 - 0.17 c 5 Hollow brick 50 0.32 - 6 Gypsum plaster 15 0.57 - , = 0.13 (m 2 ·K)/W b , = 0.04 (m 2 ·K)/W b  = 1.0385 d # Component C-2 s (mm) λ (W/(m·K)) a R ((m 2 ·K)/W) Sketch 1 Cement mortar 15 1.30 - 2 Perforated brick 115 0.35 - 3 Cement mortar 10 1.30 - 4 Extruded polystyrene (XPS) insulation 35 0.036 - 5 Air gap 10 - 0.15 c 6 Hollow brick 50 0.32 - 7 Gypsum plaster 15 0.57 - , = 0.13 (m 2 ·K)/W b , = 0.04 (m 2 ·K)/W b  = 1.0385 d # Component C-3 s (mm) λ (W/(m·K)) a R ((m 2 ·K)/W) Sketch 1 Cement mortar 15 1.30 - 2 Solid brick 115 0.85 - 3 Cement mortar 10 1.30 - 4 Air gap 100 - 0.18 c 5 Hollow brick 50 0.32 - 6 Cement mortar 15 1.30 - 7 Ceramic tiles 10 1.30 - , = 0.13 (m 2 ·K)/W b , = 0.04 (m 2 ·K)/W b  = 1.0385 d # Component C-4 s (mm) λ (W/(m·K)) a R((m 2 ·K)/W) Sketch 1 Perforated brick 115 0.35 - 2 Cement mortar 15 1.30 - 3 Extruded polystyrene (XPS) insulation 30 0.036 - 4 Air gap 70 - 0.18 c 5 Hollow brick 70 0.32 - 6 Gypsum plaster 15 0.57 - , = 0.13 (m 2 ·K)/W b , = 0.04 (m 2 ·K)/W b  = 1.0385 d # Component C-5 s (mm) λ (W/(m·K)) a R ((m 2 ·K)/W) Sketch 1 Perforated brick 115 0.35 - 2 Cement mortar 10 1.30 - 3 Air gap 100 - 0.18 c 4 Hollow brick 70 0.32 - 5 Gypsum plaster 15 0.57 - ,=0.13 (m 2 ·K)/W b ,=0.04 (m 2 ·K)/W b  = 1.0385 d # Component C-6 s (mm) λ (W/(m·K)) a R ((m 2 ·K)/W) Sketch 1 Cement mortar 20 1.30 - 2 Perforated brick 115 0.35 - 3 Cement mortar 10 1.30 - 4 Mineral wool (MW) insulation 20 0.05 - 5 Air gap 50 - 0.18 c 6 Hollow brick 70 0.32 - 7 Gypsum plaster 15 0.57 - , = 0.13 (m 2 ·K)/W b , = 0.04 (m 2 ·K)/W b  = 1.0385 d # Component C-7 s (mm) λ (W/(m·K)) a R ((m 2 ·K)/W) Sketch 1 Cement mortar 25 1.30 - 2 Perforated brick 115 0.35 - 3 Cement mortar 10 1.30 - 4 Polyurethane (PUR) insulation 40 0.028 - 5 Air gap 100 - 0.18 c 6 Hollow brick 40 0.32 - 2 Cement mortar 10 1.30 - 3 Air gap 100 - 0.18 c 4 Hollow brick 70 0.32 - 5 Gypsum plaster 15 0.57 - Rs,in=0.13 (m2·K)/W bRs,out=0.04 (m2·K)/W bCCF = 1.0385 d # Component C-6 s(mm) λ(W/(m·K)) aR((m2·K)/W) Sketch 1 Cement mortar 20 1.30 - Energies 2018, 11, x FOR PEER REVIEW 8 of 18 Table 2. Technical characteristics and thermophysical properties of case studies 1–8. # Component C-1 s (mm) λ (W/(m·K)) a R ((m 2 ·K)/W) Sketch 1 Cement mortar 15 1.30 - 2 Perforated brick 115 0.35 - 3 Cement mortar 10 1.30 - 4 Air gap 20 - 0.17 c 5 Hollow brick 50 0.32 - 6 Gypsum plaster 15 0.57 - , = 0.13 (m 2 ·K)/W b , = 0.04 (m 2 ·K)/W b  = 1.0385 d # Component C-2 s (mm) λ (W/(m·K)) a R ((m 2 ·K)/W) Sketch 1 Cement mortar 15 1.30 - 2 Perforated brick 115 0.35 - 3 Cement mortar 10 1.30 - 4 Extruded polystyrene (XPS) insulation 35 0.036 - 5 Air gap 10 - 0.15 c 6 Hollow brick 50 0.32 - 7 Gypsum plaster 15 0.57 - , = 0.13 (m 2 ·K)/W b , = 0.04 (m 2 ·K)/W b  = 1.0385 d # Component C-3 s (mm) λ (W/(m·K)) a R ((m 2 ·K)/W) Sketch 1 Cement mortar 15 1.30 - 2 Solid brick 115 0.85 - 3 Cement mortar 10 1.30 - 4 Air gap 100 - 0.18 c 5 Hollow brick 50 0.32 - 6 Cement mortar 15 1.30 - 7 Ceramic tiles 10 1.30 - , = 0.13 (m 2 ·K)/W b , = 0.04 (m 2 ·K)/W b  = 1.0385 d # Component C-4 s (mm) λ (W/(m·K)) a R((m 2 ·K)/W) Sketch 1 Perforated brick 115 0.35 - 2 Cement mortar 15 1.30 - 3 Extruded polystyrene (XPS) insulation 30 0.036 - 4 Air gap 70 - 0.18 c 5 Hollow brick 70 0.32 - 6 Gypsum plaster 15 0.57 - , = 0.13 (m 2 ·K)/W b , = 0.04 (m 2 ·K)/W b  = 1.0385 d # Component C-5 s (mm) λ (W/(m·K)) a R ((m 2 ·K)/W) Sketch 1 Perforated brick 115 0.35 - 2 Cement mortar 10 1.30 - 3 Air gap 100 - 0.18 c 4 Hollow brick 70 0.32 - 5 Gypsum plaster 15 0.57 - ,=0.13 (m 2 ·K)/W b ,=0.04 (m 2 ·K)/W b  = 1.0385 d # Component C-6 s (mm) λ (W/(m·K)) a R ((m 2 ·K)/W) Sketch 1 Cement mortar 20 1.30 - 2 Perforated brick 115 0.35 - 3 Cement mortar 10 1.30 - 4 Mineral wool (MW) insulation 20 0.05 - 5 Air gap 50 - 0.18 c 6 Hollow brick 70 0.32 - 7 Gypsum plaster 15 0.57 - , = 0.13 (m 2 ·K)/W b , = 0.04 (m 2 ·K)/W b  = 1.0385 d # Component C-7 s (mm) λ (W/(m·K)) a R ((m 2 ·K)/W) Sketch 1 Cement mortar 25 1.30 - 2 Perforated brick 115 0.35 - 3 Cement mortar 10 1.30 - 4 Polyurethane (PUR) insulation 40 0.028 - 5 Air gap 100 - 0.18 c 6 Hollow brick 40 0.32 - 2 Perforated brick 115 0.35 - 3 Cement mortar 10 1.30 - 4Mineral wool (MW) insulation 20 0.05 - 5 Air gap 50 - 0.18 c 6 Hollow brick 70 0.32 - 7 Gypsum plaster 15 0.57 - Rs,in = 0.13 (m2·K)/W bRs,out = 0.04 (m2·K)/W bCCF = 1.0385 d # Component C-7 s(mm) λ(W/(m·K)) aR((m2·K)/W) Sketch 1 Cement mortar 25 1.30 - Energies 2018, 11, x FOR PEER REVIEW 8 of 18 Table 2. Technical characteristics and thermophysical properties of case studies 1–8. # Component C-1 s (mm) λ (W/(m·K)) a R ((m 2 ·K)/W) Sketch 1 Cement mortar 15 1.30 - 2 Perforated brick 115 0.35 - 3 Cement mortar 10 1.30 - 4 Air gap 20 - 0.17 c 5 Hollow brick 50 0.32 - 6 Gypsum plaster 15 0.57 - , = 0.13 (m 2 ·K)/W b , = 0.04 (m 2 ·K)/W b  = 1.0385 d # Component C-2 s (mm) λ (W/(m·K)) a R ((m 2 ·K)/W) Sketch 1 Cement mortar 15 1.30 - 2 Perforated brick 115 0.35 - 3 Cement mortar 10 1.30 - 4 Extruded polystyrene (XPS) insulation 35 0.036 - 5 Air gap 10 - 0.15 c 6 Hollow brick 50 0.32 - 7 Gypsum plaster 15 0.57 - , = 0.13 (m 2 ·K)/W b , = 0.04 (m 2 ·K)/W b  = 1.0385 d # Component C-3 s (mm) λ (W/(m·K)) a R ((m 2 ·K)/W) Sketch 1 Cement mortar 15 1.30 - 2 Solid brick 115 0.85 - 3 Cement mortar 10 1.30 - 4 Air gap 100 - 0.18 c 5 Hollow brick 50 0.32 - 6 Cement mortar 15 1.30 - 7 Ceramic tiles 10 1.30 - , = 0.13 (m 2 ·K)/W b , = 0.04 (m 2 ·K)/W b  = 1.0385 d # Component C-4 s (mm) λ (W/(m·K)) a R((m 2 ·K)/W) Sketch 1 Perforated brick 115 0.35 - 2 Cement mortar 15 1.30 - 3 Extruded polystyrene (XPS) insulation 30 0.036 - 4 Air gap 70 - 0.18 c 5 Hollow brick 70 0.32 - 6 Gypsum plaster 15 0.57 - , = 0.13 (m 2 ·K)/W b , = 0.04 (m 2 ·K)/W b  = 1.0385 d # Component C-5 s (mm) λ (W/(m·K)) a R ((m 2 ·K)/W) Sketch 1 Perforated brick 115 0.35 - 2 Cement mortar 10 1.30 - 3 Air gap 100 - 0.18 c 4 Hollow brick 70 0.32 - 5 Gypsum plaster 15 0.57 - ,=0.13 (m 2 ·K)/W b ,=0.04 (m 2 ·K)/W b  = 1.0385 d # Component C-6 s (mm) λ (W/(m·K)) a R ((m 2 ·K)/W) Sketch 1 Cement mortar 20 1.30 - 2 Perforated brick 115 0.35 - 3 Cement mortar 10 1.30 - 4 Mineral wool (MW) insulation 20 0.05 - 5 Air gap 50 - 0.18 c 6 Hollow brick 70 0.32 - 7 Gypsum plaster 15 0.57 - , = 0.13 (m 2 ·K)/W b , = 0.04 (m 2 ·K)/W b  = 1.0385 d # Component C-7 s (mm) λ (W/(m·K)) a R ((m 2 ·K)/W) Sketch 1 Cement mortar 25 1.30 - 2 Perforated brick 115 0.35 - 3 Cement mortar 10 1.30 - 4 Polyurethane (PUR) insulation 40 0.028 - 5 Air gap 100 - 0.18 c 6 Hollow brick 40 0.32 - 2 Perforated brick 115 0.35 - 3 Cement mortar 10 1.30 - 4Polyurethane (PUR) insulation 40 0.028 - 5 Air gap 100 - 0.18 c 6 Hollow brick 40 0.32 - 7 Gypsum plaster 15 0.57 - Rs,in = 0.13 (m2·K)/W bRs,out = 0.04 (m2·K)/W bCCF = 1.0403 d Energies 2018,11, 360 9 of 17 Table 2. Cont. # Component C-8 s(mm) λ(W/(m·K)) aR((m2·K)/W) Sketch 1 Cement mortar 15 1.30 - Energies 2018, 11, x FOR PEER REVIEW 9 of 18 7 Gypsum plaster 15 0.57 - , = 0.13 (m2·K)/W b , = 0.04 (m2·K)/W b = 1.0403 d # Component C-8 s (mm) λ (W/(m·K)) aR ((m2·K)/W) Sketch 1 Cement mortar 15 1.30 - 2 Perforated brick 115 0.35 - 3 Cement mortar 10 1.30 - 4 Polyurethane (PUR) insulation 35 0.028 - 5 Air gap 10 - 0.15 c 6 Hollow brick 70 0.32 - 7 Gypsum plaster 15 0.57 - , = 0.13 (m2·K)/W b , = 0.04 (m2·K)/W b = 1.0403 d : thickness; : thermal conductivity; : thermal resistance; a Thermal conductivity of each layer obtained from the Spanish standard [43]; b Surface thermal resistance obtained from ISO 6946 [17]; c Thermal resistance of air gap obtained from ISO 6946 [17] according to its thickness; d Conductivity correction factor given by Pérez-Bella et al. [38]. Table 3. Main technical specifications of the employed equipment. Equipment Measuring Range Resolution Accuracy Data logger A with thermocouples K Temperature −10 °C to 105 °C 0.1 K ±0.05 K ±0.05% with thermocouples K Temperature −200 °C to 205 °C 0.1 K ±0.05 K ±0.05% Data logger B with thermocouples K Temperature −20 °C to 70 °C 0.1 °C ±0.1 °C with thermohygrometer Temperature −20 °C to 70 °C 0.1 °C ±0.3 °C Infrared camera FLIR E60bx (FLIR systems, Portland, OR, USA) Field of view (FOV) 25° × 19° Spectral range 7.5 µm to 13 µm Thermal sensitivity <0.05 °C to 30 °C Infrared camera Fluke TiR1 (Fluke Corporation, Everett, WA, USA) Field of view (FOV) 23° × 17° Spectral range 7.5 to 14 µm Thermal sensitivity <0.07 °C to 30 °C Weather station PCE-FWS20 (PCE Instruments, Southampton, UK) Temperature −40 °C to 65 °C 0.1 °C ±1 °C Wind speed 0 km/h to 180 km/h 0.07 m/s ±10% Precipitation 0 mm to 9.99 mm 0.1 mm ±1 mm 5. Analysis and Results The measured values during the experimental campaign for the different case studies can be seen in Figure 3. To show a simpler graphic, only the values measured by one of the data loggers are represented. Figure 4 represents the average values and the uncertainty estimations of the case studies obtained by means of THM. Furthermore, the estimated and obtained thermal transmittance values are reported in Table 4. It is important to highlight the following aspects of the measured values: • As can be observed, there were difficulties in the case studies (except in C-2 and C-5) to find observations with a difference higher than 10 °C between indoor and outdoor air temperatures. Also, in the case studies carried out during winter (C-1 and C-3), the largest temperature difference between the outdoor and the indoor air temperature was 7.2 °C, with values of the maximum temperature reaching up to 20.5 °C, which are records more commonly found in spring than in winter. For C-6 and C-8, there were few instances of a temperature difference registered higher than 5 °C. • In most case studies, the value of the indoor air temperature was constant but with slight variations. 2 Perforated brick 115 0.35 - 3 Cement mortar 10 1.30 - 4Polyurethane (PUR) insulation 35 0.028 - 5 Air gap 10 - 0.15 c 6 Hollow brick 70 0.32 - 7 Gypsum plaster 15 0.57 - Rs,in = 0.13 (m2·K)/W bRs,out = 0.04 (m2·K)/W bCCF = 1.0403 d s : thickness; λ : thermal conductivity; R : thermal resistance; a Thermal conductivity of each layer obtained from the Spanish standard [ 43 ]; b Surface thermal resistance obtained from ISO 6946 [ 17 ]; c Thermal resistance of air gap obtained from ISO 6946 [17] according to its thickness; dConductivity correction factor given by Pérez-Bella et al. [38]. Table 3. Main technical specifications of the employed equipment. Equipment Measuring Range Resolution Accuracy Data logger A with thermocouples K Temperature −10 ◦C to 105 ◦C 0.1 K ±0.05 K ±0.05% with thermocouples K Temperature −200 ◦C to 205 ◦C 0.1 K ±0.05 K ±0.05% Data logger B with thermocouples K Temperature −20 ◦C to 70 ◦C 0.1 ◦C±0.1 ◦C with thermohygrometer Temperature −20 ◦C to 70 ◦C 0.1 ◦C±0.3 ◦C Infrared camera FLIR E60bx (FLIR systems, Portland, OR, USA) Field of view (FOV) 25◦×19◦ Spectral range 7.5 µm to 13 µm Thermal sensitivity <0.05 ◦C to 30 ◦C Infrared camera Fluke TiR1 (Fluke Corporation, Everett, WA, USA) Field of view (FOV) 23◦×17◦ Spectral range 7.5 to 14 µm Thermal sensitivity <0.07 ◦C to 30 ◦C Weather station PCE-FWS20 (PCE Instruments, Southampton, UK) Temperature −40 ◦C to 65 ◦C 0.1 ◦C±1◦C Wind speed 0 km/h to 180 km/h 0.07 m/s ±10% Precipitation 0 mm to 9.99 mm 0.1 mm ±1 mm 5. Analysis and Results The measured values during the experimental campaign for the different case studies can be seen in Figure 3. To show a simpler graphic, only the values measured by one of the data loggers are represented. Figure 4represents the average values and the uncertainty estimations of the case studies obtained by means of THM. Furthermore, the estimated and obtained thermal transmittance values are reported in Table 4. It is important to highlight the following aspects of the measured values: • As can be observed, there were difficulties in the case studies (except in C-2 and C-5) to find observations with a difference higher than 10 ◦ C between indoor and outdoor air temperatures. Also, in the case studies carried out during winter (C-1 and C-3), the largest temperature difference between the outdoor and the indoor air temperature was 7.2 ◦ C, with values of the maximum temperature reaching up to 20.5 ◦ C, which are records more commonly found in spring than in winter. 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