DEEP is continuing to carry out its mission and provide services while keeping both the public and our workforce safe during the COVID-19 pandemic. Click here for the latest updates on DEEP's response to COVID-19. DEEP COVID-19 Response

Mercury Thermostat Management

Round Thermostat

In response to studies indicating high mercury deposition levels in the northeast and unsafe mercury levels in fish in Connecticut, our legislature, in cooperation with the other northeast states,  passed the most stringent mercury products legislation in the country.  Among other provisions, mercury thermostats were banned from sale in Connecticut in 2004.  Many other states followed suit and now manufacturers no longer offer mercury thermostats for sale.

However many mercury thermostats remain in service and it is important to keep the mercury from entering the environment once they are replaced or taken out of service.  Manufacturers distributors, municipalities, contractors, businesses, and homeowners all have a role to play. 

Connecticut's Thermostat Stewardship Law

How to Properly Dispose of a Mercury Thermostat

Information for Manufacturers

Information for Wholesalers

Information for Demolition and HVAC Contractors

Information for Municipalities

Information for Residents

Additional Resources

Connecticut’s Thermostat Stewardship Law

In order to increase the recovery of mercury thermostats, in 2012 the Connecticut legislator passed Public Act 12-54, AN ACT REQUIRING THE ESTABLISHMENT OF MANUFACTURER MERCURY THERMOSTAT COLLECTION AND RECYCLING PROGRAMS. The law requires manufacturers to establish a collection system for the recovery of mercury thermostats. Under the provisions of that law, manufacturers, wholesalers and qualified contractors, demolition contractors, and every person each have responsibilities under the law.

The Thermostat Recycling Corporation (TRC) is a non-profit organization established in 1998 by the manufacturers of mercury thermostats. In response to the law, the TRC has set up a program to recover and recycle mercury thermostats using a network of collection sites, primarily wholesalers that carry thermostats.

  • Annual Report on Mercury-added Thermostat Collection & Recycling in Connecticut: 2013

Information for Manufacturers

In accordance with PA 12-54, manufacturers of mercury thermostats must:

  • By April 1, 2013, establish a program for the recovery of mercury thermostats. Manufacturers have fulfilled this requirement through the Thermostat Recycling Corporation (TRC);
  • Provide a storage container for any wholesaler, retailer, qualified contractor (employs seven or more technicians who service thermostats or is outside an urban area) or municipality who requests one;
  • Provide educational material with each container;
  • Promote the recovery program;
  • Report to DEEP annually on the effectiveness of the program.

Information for Wholesalers and Installers

In accordance with PA 12-54, wholesalers* of mercury thermostats and qualified contractors** who install mercury thermostats:

  • By July 1, 2014, must participate in the program by maintaining a collection container and posting informational material;
  • After July 1, 2014, may not sell any type of thermostat unless they participate in the program.

* Defined in the statute as selling thermostats.

** Defined in the statute as any contractor who employs seven or more service technicians or installers or who is located in an area outside of an urban area.

Information for Demolition and HVAC Contractors

In accordance with PA 12-54:

  • After July 1, 2014, any contractor who replaces a mercury thermostat must participate in the program or recycle mercury thermostats independently;
  • May not place mercury thermostats in the trash;
  • After July 1, 2014, demolition contractors must remove and recycle mercury thermostats prior to demolition and recycle them either through the TRC program or independently through a licensed hazardous waste contractor:
  • An HVAC company that has seven or more service technicians or installers is considered a “qualified contractor” and is entitled to a mercury thermostat collection container from the TRC.  To request a container, visit the TRC website.

Information for Residents

  • After July 1, 2014 Connecticut residents may not throw mercury thermostats in the trash.
  • To find a mercury thermostat recycling location, go to the TRC website and type your zip code into the locator tool at the top of the page.  It is advisable to double-check with the location you choose to confirm that they will accept your thermostat.
  • You may also bring them to a household hazardous waste collection.

Information for Municipalities

  • Municipalities can serve as a collection point for mercury thermostats. The Municipal Transfer Station General Permit does allow for the collection of mercury thermostats.
  • The TRC will provide a container to any transfer station or permanent household hazardous waste facility that requests one.  They will assess a onetime fee of up to $75. Once the container is full, it can be mailed back to the contracted mercury processing facility. To request a container, visit the TRC website.

How to Properly Dispose of a Mercury Thermostat

The newer digital and programmable thermostats are a great way to save energy and lower your heating bills. If you decide to replace a mercury thermostat with a newer model, it is important to properly dispose of the unwanted thermostat.

The first step is to determine if the old thermostat contains mercury. Carefully remove the face plate of the old thermostat. A mercury thermostat will have one or more glass ampoules containing a silver mass of mercury. DO NOT BREAK OR REMOVE THE AMPOULES!   Pictured below is an image of a typical mercury thermostat and the mercury ampoules it contains:

Thermostat with CoverRight ArrowTypical ThermostatRight ArrowMercury Thermostat Ampoules


If you determine that the thermostat contains mercury, you can bring it a household hazardous waste collection or a electrical wholesaler that participates in the Thermostat Recycling Corporation (TRC) program. To find a TRC location, go to the TRC website and type your zip code into the locator tool at the top of the page.  It is advisable to double-check with the location you choose to confirm that they will accept your thermostat.

If you have a mercury thermostat replaced by a professional, make sure the technician properly disposes of the thermostat.

If you have a mercury spill, please report it to the CT DEEP 24-hour Emergency Response and Spill Prevention Hotline at:
860-424-3338 or Toll Free at 1-866-DEP-SPIL (1-866-337-7745)
If these numbers are unavailable for any reason, call (860) 424-3333

Additional Resources

TRC Training Video for HVAC Wholesalers and other Collection Locations  (You Tube)

TRC Video on Preventing Mercury Pollution  (You Tube)

Webinar slide presentations, June 24, 2013:


Content Last Updated January 14, 2015