The term “smart thermostat” generally refers to devices that have two specific capabilities:
(a) the ability to run programs for each day of the week that use temperature setbacks during expected unoccupied periods and (b) external communications that may include, but are not limited to, Internet connectivity, mobile application (app) access, and data reporting.
In comparison to programmable thermostats, the smart thermostats are designed to be more user-friendly. Smart thermostats are designed to take notice of a home’s energy use patterns and make assumptions based on such. The programmable thermostats are often not used to their potential because most people don’t actually use them to schedule their thermostats to be set back for a duration and save money.
One key difference between smart thermostats and programmable thermostats is the ease of creating schedules for users. Although traditional programmable thermostats required users to program exact times for their schedules, these newer devices are more intuitive and don’t require as much time or engagement from the user. Most devices build a schedule by asking users simple questions during setup to understand the residents’ typical schedules and comfort preferences. Questions like “What time do you typically leave in the morning?” and “What is an acceptable indoor temperature during the summer while you’re away?” provide the input for the thermostats to build the setback schedules.
In the case of the Nest, the device learns when residents are home based on manual setbacks and the use of an occupancy sensor. This means that Nest owners are asked to treat the Nest like a manual thermostat for approximately the first week it is installed, manually turning it down when they leave for work or go to sleep, and returning the temperature to a preferred setpoint when they return home from work or wake up. After accumulating about a week’s worth of data, the Nest will create a setback schedule for the home. Regardless of the vendor, each product claims to make it easy for users to adjust schedules if they see fit.
For the more-engaged user, most smart thermostat vendors offer an online platform and mobile app that provide access to the thermostat. This allows users to change temperature setpoints and program settings on the fly. For example, if a user will be arriving home earlier than usual one night during the week, he could access the thermostat on his smartphone or desktop computer and change the thermostat’s program setting from Away to Occupied before leaving the office. The thermostat would then begin a temperature recovery process to bring the home back to the Occupied settings before he arrives home.
Smart thermostat vendors share that the overwhelming majority of their users – 80 percent or more – actively use programmed schedules. This compares favorably, which says that only about 50 percent of programmable thermostat users actually use programmed schedules. Furthermore, vendors said that users were averaging 7 to 10 logins to the online portal or mobile app each week. Though it’s reasonable to assume this login number could decrease over time, it shows that people are willing and able to program smart thermostats if they’re given easy-to-use tools.
It’s important to keep in mind that smart thermostats will be most useful when used with a wi-fi connection. All three thermostats are available for purchase online or through contractors. The Honeywell Prestige is available in major hardware stores and The Nest is available at electronic stores.
One of the Nest’s appealing features is the schedule builder. Rather than asking specific questions about users’ schedules and comfort preferences, the Nest uses actual usage data to build a schedule for its users. The instructions direct new owners to use the Nest as a manual thermostat for the first week, as well as selecting preferred comfort setpoints during times when the home is occupied and residents are awake and active. After several days (usually five), the Nest builds a programmed schedule based on the times the user changed the setpoints and the settings the user selected. Users can fine-tune the schedule too, either on the device or through the online portal or mobile app.
Some other features unique to the Nest are intended to educate homeowners about energy-saving behaviors. The Nest has an Energy History feature, where users can see how often their heating or cooling systems ran over the previous 10 days. Energy history can also tell users whether the energy increase or decrease was due to their behavior (setpoint changes), automatic features (auto-away was engaged), or outdoor weather, which the device monitors via its online connection. The Nest also displays a green leaf icon on the device to show users when they’re choosing a more economical setpoint.
The ecobee thermostat creates setback programs for its users based on answers to questions asked during setup that revolve around when the users are home and awake. ecobee claims that of the users who have downloaded the mobile app, 78 percent of them access it at least once a week.
In addition, ecobee offers customers an energy usage portal that stores up to 15 months of data, giving users the ability to perform year-over-year comparisons. The usage charts include several data streams beyond equipment run time too, including indoor and outdoor air temperature, indoor air temperature setpoint, actual indoor air temperature, and indoor humidity.
Thermostats from ecobee can also provide maintenance reminders and system alerts if users choose. Standard maintenance reminders would include general reminders for HVAC service and tune-ups—where the user specifies a monthly schedule for reminders—and a reminder to change filters, either at a regular time interval or based on equipment run time. Users can also receive reminders to change UV filters if they have them. When system alerts are set up, users will be notified if temperatures exceed predetermined maximum or minimum temperatures; similar alerts can be set for humidity levels.
The Honeywell Prestige’s unique feature is the way it connects to the cloud, through an online portal called “My Connect.” Rather than using standard Wi-Fi, it uses a proprietary wireless technology. Honeywell originally developed this technology for its security products, but tailored it to fit the needs of the home energy and light commercial markets.
The advantage of this technology is that users can connect up to six different accessories to the Prestige. These include wireless indoor and outdoor temperature sensors, three different types of remotes—two are stationary, would be placed at the front and back door, and have simple onetouch controls to change thermostat settings like Home, Away, or Sleep; the third can be carried around the home and has more functionality. Honeywell’s My Connect portal allows users to connect multiple thermostats. In fact, users have no limit to the number of devices and locations they link to the portal. Users can set these thermostats as residential or commercial, too; this will change the language used on the portal and the device. For example, a device that’s deemed residential will use terms like Home, Away, or Sleep for scheduled periods; a commercial device will use terms like Occupied, Unoccupied, and Holiday.
Other features include a scheduling wizard that asks users questions about the user’s lifestyle and how they come and go, and then builds a schedule based on the answers. The Prestige also uses temperature alerts to notify users of pending emergencies. When temperatures get too low or too high (such as in a server room), the Prestige will send a notification to the user that the temperature has reached an excessive level.