Connected Thermostat Efficiency Program Heats Up

Tue, 04/12/2016 - 16:26 -- MrGreen

In 2014, the U.S. Environmental Protection Agency embarked on a new approach for ENERGY STAR recognition of smart thermostats, focusing on "demonstrated" consumer home energy savings. The agency is now working with stakeholders on the second draft of a new specification for a new product group called "Connected Thermostats" (CT).

The EPA defines a CT as a product that controls an area's heating, ventilation, and air conditioning (HVAC) with the added ability to communicate with external sources. Communication typically is through a home WiFi network and an internet connection independent to the thermostat. Any products without the ability to collect and transmit required energy savings data is excluded from this program.

Key changes incorporated into Draft 2 include:

  • Addition of a standby power and static temperature accuracy test method
  • Removal of the requirement for occupancy sensing
  • Simplified grid response requirements in recognition of the many demand response options currently available from connected thermostat service providers
  • Options to verify actual field performance energy savings

In its present form, the draft specification requires that a product must first meet the performance requirements shown below:

Parameter Performance Requirement
Static Temperature Accuracy ± 1.0°F
Network Standby average power consumption1 ≤ 2 W average
Time to enter networked standby after user interaction (on device, remote, or occupancy detection) ≤ 5 minutes

1. Includes all equipment necessary to establish connectivity except those that are typically present in the home (i.e. Wi-Fi routers and smart phones)

In addition to these requirements, a connected thermostat must demonstrate a minimum level of typical field performance. The performance metrics are currently being developed but are expected to include minimum requirements for average annual run time reductions for heating and for air conditioning. Draft 2 also proposes an option for manufacturers to demonstrate field savings through a comparative study instead of meeting specific metric performance requirements.

Partners and other interested parties who would like to participate in this process should send their contact information to to be added to the distribution list for updates. Additional information including the current specification draft, previous meeting presentations, and stakeholder comments can be found on the Connected Thermostats Specification V1.0 web page.