Honeywell thermostats are no longer classified as energy-efficient devices by the Department of Energy's Energy Star program. The Energy Star specification was suspended for all programmable thermostats in December 2009.
The Energy Star specification for thermostats was suspended due to inconclusive evidence that the programmable thermostats made by any manufacturers were substantially more efficient than other models. However, the Department of Energy continues to advise homeowners that a properly used programmable thermostat does improve energy use overall. Setting a programmable thermostat to reduce heating and cooling during the day and late at night can reduce energy costs by about $180 a year for most homes.