## 2 Materials and Methods
### Self-Adjustment Procedure in Real Conditions  
For the demonstration of the proposed technique in real conditions, a residential building in Pulovice (distr. Karlovy Vary), Czech Republic was selected. All necessary data and parameters including climatic variables, structural aspects, material properties, and indoor environmental variables were acquired during that experiment. The summary of data collected within the field survey and experimental measurements is shown in Figure 3.  
Figure 2: Scheme of the adjustment approach with an independent validation.  
The realization of the in-situ experiment including a description of the experimental equipment is documented in Figure 4.  
The wall was built from autoclaved aerated concrete (AAC) blocks with a thickness of 500 mm which were rendered with a plaster on the exterior surface only. The missing interior render helped to better analyze the background of the heat transport processes in the surface layers as the material characteristics of AAC are known very well and the potential sources of uncertainties could be significantly reduced by a simple visual check. In this way, sources of inhomogeneities or hidden materials in the wall composition could be excluded, which was very appreciating for the adjustment of the computational model. Otherwise, a pre-experimental site inspection using, for example, infrared thermography would be needed as required by C1046 [23].  
Figure 4: The realization of the in-situ experiment.  
Figure 3: Experimental measurement and input data overview.  
The outdoor data were collected using the Davis Vanatge Pro2 weather station in 30-min intervals. At the same time resolution, the indoor data were collected using a MS6D Dataloger (by Comet System Ltd., Bratislava, Czech Republic) equipped with two T/RH sensors and two thin-foil heat flux probes Hukseflux FHF01.  
Hukseflux sensors are considered thermopiles [35; 36], i.e., they consist of a series of thermocouples that measure the temperature difference across the sensor body. The FHF01 is a very thin and flexible foil sensor for general-purpose heat flux measurements equipped with the type T thermocouple to monitor the surface temperature along with the heat flux. The sensor is designed for the measurements of heat flux in the range from \(-200\) to 200 W\(\cdot\)m\({}^{-2}\) with a nominal sensitivity of \(4.5\times 10^{-6}\) V\(\cdot\)m\({}^{2}\cdot\)W\({}^{-1}\).  
Taking into account specific building-related conditions, such as surface roughness, various types of mountings, and low thermal conductivity of materials, or the conjunction of those factors, the default factory calibration should not always be suitable for heat flux measurement under such conditions. Therefore, a custom sensitivity adjustment approach is presented with the experimental setup described above, which does not require any additional equipment (such as foil heaters) or actions (sensor removal or replacement). Since all probes are classified as thermopiles, i.e., they produce raw data in the form of time-resolved voltage; a user-defined adjustment procedure seems to be optimal to get sufficiently accurate results for each specific application. To guarantee that the overall performance of the building element will be measured, and representative site conditions will be recorded, multiple heat flux sensors were involved in the experimental setup. The summary of input data and parameters that are necessary for both experimental measurement, computational simulation, and in-situ data analysis are shown in Table 1. Here, the following symbols are used: \(\rho_{\mathrm{v}}\) (kg\(\cdot\)m\({}^{-3}\)) for the bulk density, \(\rho\) (kg\(\cdot\)m\({}^{-3}\)) for the matrix density (kg\(\cdot\)m\({}^{-3}\)), and \(c\) (J\(\cdot\)kg\({}^{-1}\cdot\)K\({}^{-1}\)) is the specific heat capacity.