Smart thermostats are similar to programmable thermostats in the sense that they have a scheduling feature that allows users to set different temperatures for different times of the day. In addition to this feature, smart thermostats implement other technologies to reduce the amount of human error involved with using programmable thermostats. Smart thermostats incorporate the use of sensors that determine whether or not the home is occupied and can suspend heating or cooling until the occupant returns. Additionally, smart thermostats utilize Wi-Fi connectivity to give the user access to the thermostat at all times. These additional technologies have proven to make smart thermostats successful in saving users energy and money.

The programmable schedule feature on the smart thermostat is similar to that on standard programmable thermostats. Users are given the option to program a custom schedule to reduce energy usage when they are away from the home. Studies have shown, though, that manually creating a schedule may lead to more energy usage than just keeping the thermostat at a set temperature. To avoid this problem, smart thermostats also provide an auto schedule feature. This feature requires the use of algorithms and pattern recognition to create a schedule that results in occupant comfort and energy savings. Upon creating a schedule, the thermostat will continue monitoring occupant behavior to make changes to the auto schedule. By taking the human error out of the scheduling, smart thermostats can create smart schedules that actually save energy.

Another major feature of smart thermostats is their ability to connect to the internet. Smart thermostats are designed with a WiFi module that allows the thermostat to connect to the users home or office network and interface with a web portal or smart phone application, allowing users to control the unit remotely. The WiFi feature also has the ability to send reports on energy usage and HVAC system performance via the web portal, informing the user on their energy efficiency and how it compares to other smart thermostat users. It also alerts users when a problem arises with their HVAC system or when it is time for equipment maintenance. The thermostat also uses the WiFi connection to display current weather conditions and the weather forecast. Another feature offered by some smart thermostats through the internet connection is geofencing. A geofence is a perimeter boundary created around the location of a smart phone or other device, based on GPS signals. The benefit of having a smart thermostat with geofencing capabilities is that it uses a users smart phone location to determine whether the home is occupied. Instead of using a schedule or sensor to determine occupancy, the smart thermostat can rely on the location of the geofence to tell the HVAC system whether it needs to be on or off. Since most people carry their phones with them, geofencing can be an accurate way to determine occupancy patterns.

Another discrepancy to consider is the population of people involved in the study. Some studies, such as the My Energy study, involve people who signed up for an energy analysis program.These people are likely to be more energy conscious and efficient and have better heating and cooling practices. This greater interest in energy efficiency may lead to lower energy savings by switching to a smart thermostat. The most energy-conscious customers are the ones more likely to have had efficient thermostat settings, therefore, the savings that they receive from the smart thermostat may not be as great.