Process

The problem space of this project is that many people’s mental model of how a thermostat works is different from the real working principle of a thermostat. In the summer, many people tend to turn down the temperature lower than they actually need to because they think this will make the thermostat work faster. This is not the case, because a thermostat is not actually a continuous control, but rather a switch. We tried to design an interface to inform users that the range of temperature change is not related to the working speed of a thermostat.

Our initial design has a line of dots as a progress bar to display the distance between the actual and set temperatures, approximating the time required to reach the desired temperature. The greater the distance, the more dots will turn to larger circles. As the thermostat works, the circles will gradually turn back into little dots, showing the passage of time. We designed this line of dots in order to help users understand that the further they adjust the temperature, the longer they have to wait. To avoid waiting a long time, users will adjust the temperature less and to a more reasonable number.

Usability testing for the initial design showed that the progress bar did not have the desired effect of preventing misunderstanding of the operational model. To address this finding, we changed this design to a combination of recommending a temperature to the user and showing a hint message when changing the set temperature too drastically. We added a recommended temperature on the top of the screen, and by pressing the “Enter” button users can make the thermostat start working toward the recommended temperature. We hope by providing this easy “one-press” operation users will be encouraged to choose the recommended temperature instead of adjusting the temperature drastically. If the user adjusts the temperature more than 10°F (5°C) from the current (“actual”) inside temperature, a message will appear to the user saying, “Drastic changes in temperature can greatly reduce the efficiency of the heating/cooling system”. It will appear only once, but the user must acknowledge the message, requiring them to move their hand away from the arrow buttons and encouraging them to pause and think about the temperature they are setting.

My Role

• Co-created personas for design.
• Co-sketched and designed prototyped with features and workflows in the thermostat.
• Co-conducted usability testing using paper prototype.
• Co-wrote design document describing personas, design rational, and usability testing.