Interestingly, as seen in Figure 11, some overheating and overcooling is observed in October, when the house is already mechanically heated. From the outdoor temperature and solar irradiation it seems that occupants opened the windows in some sunny October days, which overcooled the room. Comparing the outdoor temperature in Figure 11 with that of Bogotá (Figure 3), we can see that while locally it is common to mechanically heat our homes in October, in Bogotá, at lower outdoor temperatures this option is not even considered, no matter how clear or cloudy the sky is, or how rainy or humid the weather is. The example illustrates that when given opportunities to adapt, dwellers create indoor temperatures and expand their comfort zones. Obviously not all buildings or rooms in a house can afford cross-ventilation, or having the windows open at night. In dense urban settings, designing adaptive opportunities within the building form and character is more challenging. Designing multi-unit residential building (MURB) suites for comfort is more challenging because of high window-to-floor ratios, and operable windows that can only provide single-sided ventilation, which is not optimized (i.e. operable window type, size and placement in the exterior wall). High-end high-rise MURBs being built in Vancouver are designed with mechanical cooling with little or no consideration for solar protection or natural cooling. However, the effectiveness of single-sided ventilation for natural cooling is limited. Research studies on schools and offices show single-sided ventilation air change rates between 1 and 4 ACH, compared to 5 to 22 ACH for cross-ventilation16 . COVER STORY FIGURE 9: TEMPERATURES IN THE ROOMS OF THE HOUSE OVER A WEEK, AND WINDOW OPERATION IN THE MASTER BEDROOM. Figure 9. Temperatures in the house rooms over a week, and window operation in the master bedroom Figure 10. ATC limits and temperatures from the master bedroom from 10 PM to 7 AM FIGURE 10: ATC LIMITS AND TEMPERATURES FROM THE MASTER BEDROOM FROM 10 P.M. TO 7 A.M. Figure 8 shows large temperature variations in the master bedroom. This is explained in Figure 9: the occupants open the bedroom windows every night before going to bed, and close them early in the morning. The reason they do this is because they like cool temperatures for sleeping, which also cool down the bedroom thermal mass for the next day. As a consequence, the master bedroom temperature remains within the 80 per cent acceptability ATC bands as indicated in Figure 10, with some overheating and overcooling. Within the ATC bands, occupants are expected to readily adapt thermally in relation to the outdoor temperature. However, the ATC bands were not produced from bedroom data. A field study in the UK15 shows that quality of sleep may be compromised if the bedroom temperature rises much above 24°C. The dotted red line in Figure 10 represents a hypothetical expanded comfort zone of this house’s dwellers that reflects that given the opportunity to adapt, dwellers are willing to adapt further and expand their comfort zone. In this house, dwellers voiced no complaints with the home temperatures. 22 BCBEC ELEMENTS A BCBEC PUBLICATION