## 3 Results and Discussion
### Energy Use for Space Heating  
The average indoor temperatures were 20.0 \({}^{\circ}\)C in room A and 20.1 \({}^{\circ}\)C in room B during the heating period. Thus, although room A used more energy for space heating, the average indoor temperature was somewhat lower in that room than in room B. However, this difference was very small--only 0.1 \({}^{\circ}\)C.  
The temperature in the space surrounding the test rooms (room C) was most of the time a little bit warmer than inside the test rooms (see Figure 12). This difference accounted for a total of 6589.7 degree hours for room A and 6418.5 degree hours for room B (see Table 1). This difference was only accounted for on days when the average outdoor temperature was \(<\)19.0 \({}^{\circ}\)C, and ignored for days when the average outdoor temperature (\(\overline{T}_{e}\)) was \(\geq\)19.0 \({}^{\circ}\)C.  
The temperature in the building surrounding the two test rooms was not always exactly the same as inside the test rooms. Therefore, there was a heat flow through the internal walls, floors, and roofs of the test rooms. Overall, the temperature in the surrounding building was somewhat higher than inside the test rooms, leading to an energy gain from the surrounding building into the test rooms:  
The thermal transmittance (U) through the walls equalled  
\[U=\frac{\Phi}{(T_{1}-T_{2})\cdot A} \tag{1}\]  
thus the heat flow (\(\Phi\)) through the walls equalled  
\[\Phi=(T_{1}-T_{2})\cdot A\cdot U \tag{2}\]  
and total energy gain (dQ) was calculated as  
\[dQ=\Phi\cdot dt \tag{3}\]  
This gave an energy gain from the surrounding building into the test rooms (see Table 1). Figure 11: Daily mean indoor temperatures in room B, as measured by the ventilation system (Room B) and by the TESTO device (TESTO Room B). Room A used 563.0 kWh for space heating while room B used 350.9 kWh. However, a correction had to be made for room B because of flaws in the heating system during the holidays. The three spikes in temperature in room B (see Figure 12) were caused by a failure in the control schedule: Unfortunately, there was an alternative schedule in the system that started during the holidays which caused the system to heat room B continuously for the entire day during Christmas (25 and 26 December), New Year's Day (1 January), and Epiphany (6 January). To correct this, an analysis was made of the data for these holidays: T\({}_{\rm A}\) and T\({}_{\rm C}\). Then days with (almost) the same values for T\({}_{\rm A}\) and T\({}_{\rm C}\) were found. The values for T\({}_{\rm B}\) for these similar days were used instead for the above-mentioned holidays. The correction value for room B was 24.25 kWh for space heating. In other words, room B used 24.25 kWh too much for space heating. This was space heating that was not necessary; the temperature in room B was over 27 \({}^{\circ}\)C at Christmas, which is much higher than what was needed. Additionally, the degree hours were affected by the flaws in the heating system. Due to the high temperatures around Christmas, the difference in degree hours between room B and the surrounding building was too low. Therefore, the values for degree hours were compensated in the same manner as for the space heating data. This produced a correction of 437.3 degree hours (6418.5 = 5981.2 + 437.3) for the holiday period. This resulted in a total energy use per room for the heating season of 15 September-15 May as follows: \begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Test Room**} & **Total Degree Hours \({}^{\star}\)** & **Thermal Transmittance** & **Total Energy Gain** \\  & **[\(\Delta\)Kh]** & \(\sum\)**[W/K]** & **[kWh]** \\ \hline A & 6589.7 & 13.8 & 90.8 \\ B & 6418.5 & 13.8 & 88.4 *** \\ \hline \end{tabular} \({}^{\star}\) Difference in degree hours between the test room and the surrounding building. ** Total transmittance through the internal walls, floor and roof of the test room to the surrounding building. *** compensated values for 25–27 December, 1–2 January, 6–7 January.  
\end{table}