2.1. Winter solstice free floating temperature.

• *Comparison of simulation and monitoring:*

In the winter solstice period simulation and monitoring data follow a very similar trend (Figure 6). The thermal amplitude range is 1.5 ◦C for simulation and 2.3 ◦C for monitoring, with some specific days that can increase up to 3.7 ◦C. While the outdoor maximum temperature is at 3 p.m., inside the Earthbag building the maximum peak of temperature is produced from 1 p.m. to 2 p.m., one hour after the moment of maximum solar radiation. This peak of temperature is produced by the direct solar gain through the south glazed door. In this period of the year, the incident solar radiation in the east and west windows is inexistent and therefore no effect due to these glazed openings is observed. In a cloudy day with significantly less solar radiation, such as 11 December, there is no substantial increase of temperature from 2 p.m. to 3 p.m. In this case, the temperature oscillates moderately as if there were no windows.

**Figure 6.** Interior simulated and monitored temperature, exterior temperature, solar radiation and radiation through the glazed surface, during the winter solstice.

• *Comparison between the two simulation cases*:

When comparing the simulated data in Figure 6 with the simulated model with no windows, the effect of the direct solar gains through the south glazed opening increases the average temperature in 1.31 ◦C, during the exposed period. In both cases, the thermal lag between interior and exterior maximum temperature is about 8 h (from 3 p.m. to 11 p.m.), due to the effect of thermal inertia of the Earthbag walls. This effect is more visible in the simulated case of the building without glazed openings. If the glazed openings were covered, the thermal lag would be 7 h (from 3 p.m. to 10 p.m.) and the thermal amplitude 1.3 ◦C.

#2.2. Equinox free floating temperature.

• *Comparison of simulation and monitoring:*

During the equinox period simulation and monitoring data follow a similar trend (Figure 7). In both cases, the thermal amplitude ranges between 1.8–2.2 ◦C. While the outer maximum temperature is at 3 p.m., inside the Earthbag building the maximum is at 2 p.m., one hour after the maximum solar radiation. This peak of temperature is produced by the direct solar gain through the south glazed door. In this period of the year, the solar radiation incident in the east window is slightly noticed from 8–9 a.m. with a small increase of 0.5 ◦C in the indoor temperature, clearly visible in the simulation.

**Figure 7.** Interior simulated and monitored temperature, exterior temperature, solar radiation and radiation through the glazed surface, during the equinox.

• *Comparison between the two simulation cases:*

Compared to the simulated model with no windows, the effect of the direct solar gains increases the temperature in 1.37 ◦C. This increment of temperature is mainly due to the south glazed opening. In this case, the thermal lag of the simulated analysis between interior and exterior maximum temperature is about 7 h (from 3 p.m. to 10 p.m.), due to the effect of thermal inertia of the Earthbag walls. In the case of the Earthbag building with no glazed openings, the thermal lag is 8 h (from 3 p.m. to 11 p.m.) and an average of the thermal amplitude about 1.8 ◦C.

#2.3. Summer solstice free floating temperature.

• *Comparison of simulation and monitoring:*

In the summer solstice, the interior temperatures in the monitored and the simulated Earthbag building have a similar tendency (Figure 8). The thermal amplitude for both, simulation and monitoring is a maximum of 2.3 ◦C. The solar radiation entering through the glazed openings is visible for the three glazed surfaces in the monitoring, and barely visible in the simulation. Due to the relative position of the sun respect to the south facade, the radiation entering in the south glazed opening is inferior than in the other periods, with 200 W around midday corresponding to the maximum solar radiation (12 p.m.–1 p.m.). The shadow produced by the design of the awnings over the windows and the thickness of the Earthbag walls caused enough solar protection to minimize the solar heat gains. In this case, the maximum exterior temperature is around 4 p.m.

**Figure 8.** Interior simulated and monitored temperature, exterior temperature, solar radiation and radiation through the glazed surface, during the summer solstice.

#### • *Comparison between the two simulation cases:*

Compared to the simulated model with no windows, the effect of the direct solar gains increases the temperature in 0.52 ◦C, the lowest increase for the three analyzed periods. The thermal lag for the glazed Earthbag building simulation is about 6 h while for the simulation with no glasses is 7 h. The internal temperature thermal amplitude is about 2 ◦C for the building simulated with glazed openings and about 2.1 ◦C for the simulated building without glazed openings, when the outer temperature's amplitude is about 15 ◦C. When calculating the thermal amplitude for the monitored building, the value is about 1.2 ◦C.

#3.1. Summer 24 h cross ventilation.

The behavior of the Earthbag building under natural cross ventilation conditions (24 h per day) during summertime is presented in Figure 9. Both results of interior temperature for simulation and monitoring, present a similar trend, which validates the simulation. The thermal lag between exterior and interior temperatures is inferior to 1 h. Despite the ventilation, a decrement factor can still be observed. The mean exterior thermal amplitude is 10 ◦C, while the interior is 4 ◦C. During midday, interior temperature is almost reaching exterior temperatures (from 1 ◦C to 4 ◦C below the maximum peak temperatures). During the night, the effect of the thermal inertia of the Earthbag building is visible. Despite the ventilation, when the exterior temperature decreases drastically, the Earthbag building keeps the thermal energy and makes the interior temperature be higher than the exterior (from 3 ◦C to 5 ◦C over the minimum peak temperatures). The thermal inertia effect is also visible on 6 June (a cooler day than the previous) when the interior maximum temperatures are 2 ◦C over the exterior temperatures. The natural cross ventilation during all the day was not effective to cool down the Earthbag building because the exterior day temperatures were high enough to keep the daily average interior temperatures in a high range (20–24 ◦C). In this case, the solar radiation does not have much influence because the main temperature changes are due to the constant hot air circulation from the outside.

**Figure 9.** Indoor simulated and monitored temperature, exterior temperature and solar radiation, during 24 h natural cross ventilation scenario.
