Adding GPS-Control to Traditional Thermostats: An Exploration of Potential Energy Savings and Design Challenges

Abstract

Abstract. Although manual and programmable home thermostats can save energy when used properly, studies have shown that over 40% of U.S. homes may not use energy-saving temperature setbacks when homes are unoccupied. We propose a system for augmenting these thermostats using just-in-time heating and cooling based on travel-to-home distance obtained from location-aware mobile phones. Analyzing GPS travel data from 8 participants (8-12 weeks each) and heating and cooling characteristics from 5 homes, we report results of running computer simulations estimating potential energy savings from such a device. Using a GPSenabled thermostat might lead to savings of as much as 7% for some households that do not regularly use the temperature setback afforded by manual and programmable thermostats. Significantly, these savings could be obtained without requiring any change in occupant behavior or comfort level, and the technology could be implemented affordably by exploiting the ubiquity of mobile phones. Additional savings may be possible with modest context-sensitive prompting. We report on design considerations identified during a pilot test of a fully-functional implementation of the system.

Balance: Budget-driven smart thermostat control

“…Specifically, BALANCE is useful to those with a strong desire to keep their energy bill below a certain amount and who are willing to relax their ideal comfort requirements. We demonstrated that our simple BalancingAgent can reliably meet a reasonable user-provided budget 7 and provide at least a 40% improvement in comfort over the lowest-cost approach, given user preferences. There are also several avenues for improving the performance of the BALANCE agent that have the potential to meet the budget with more time spent in the preferred comfort range.…”

Thermostat Interface and Usability: A Survey

“…Several applications have been developed to enable control of a thermostat using a cell phone (Figure 3). Global Positioning Systems (GPS) in cell phones have been used to convey occupancy to smart thermostats, which can then predict arrival times of a home's occupants and modify the setpoint accordingly (Gupta, Intille, & Larson, 2009). An "Internet thermostat" describes a programmable thermostat that connects to an IP (Internet Protocol) network; models are currently being made by Proliphix, Aprilaire, and Ecobee (Figure 3).…”

“…Parker, Barkaszi, Sherwin, & Richardson, 1996;Rathouse & Young, 2004b) Aesthetics of the device (Gupta, et al, 2009) People want to retain control (Kempton, Reynolds, Fels, & Hull, 1992) Special HVAC systems (Evaporative Cooling, Heat Pumps) work differently than normal systems and require a different operating mode, user practice, and (Bouchelle, et al, 2000;Diamond, et al, 1996) thermostat setting High priority for heating in people's expenditures (Rathouse & Young, 2004b) Renter/Owner problem In some studies, functions like the "boost button" (an additional hour of heating (Rathouse & Young, 2004b), a timer (Kempton, Feuermann, & McGarity, 1992), and indication of the time needed to reach the desired temperature (Karjalainen, 2008) were considered useful to customers. These features are not currently available in any of the surveyed U.S. thermostats.…”

“…Cialdini suggested that showing waste or loss instead of savings can be a better incentive to conserve energy (Cialdini, 1993). In recent studies, the indication of the time expected to reach the selected temperature emerged as a very useful indication for users (Gupta, et al, 2009;Karjalainen, 2008). To implement this feedback information requires some intelligence; the devices needed to store historic internal and external temperature and HVAC cycles, and use the information to predict how quickly the room temperature is going to change.…”

“…Some examples of information needed to operate a system without human input were occupancy and thermal preference. Different original solutions have been suggested to monitor the location of household members ranging from occupancy sensors (BAYweb; Fountain, Brager, Arens, Bauman, & Benton, 1994;Peffer, 2009; RCI Automation LLC; Telkonet) to Mobile GPS (Gupta, et al, 2009). Occupancy data could also be predicted from historic energy consumption of water boilers with the addition of cheap sensors in the tank (Boait & Rylatt, 2010).…”