The burning of coal to produce energy is a major source of mercury emissions to the environment, as well as of other pollutants, particularly greenhouse gases. A mercury-switch thermostat uses mercury in a sealed glass bulb. Each bulb contains approximately three grams of mercury, which is about the size of a dime. Thermostats with mercury switches operate quietly and efficiently, require little or no maintenance, and provide up to 30 to 40 years of service. In Minnesota, Honeywell offers a free recycling program for mercury-containing thermostats.
Homeowners can recycle any brand of thermostat by mail.
Honeywell and other manufacturers plan to expand the recycling program for homeowners and dealers in other states pending regulatory permission. Last updated December 31, 1995.