Do thermostats still have mercury in them? No, never 100% Get Free Quotes Today! Question: Do thermostats still have mercury in them? Top Answer (100% of 1 votes): No, never. Answer: No, never Explanation: New thermostats no longer use mercury Construct Boss Get Free Quotes Today! Find Local Pros Free Thermostat Installation Cost Estimates Related Questions Do digital thermostats need to be calibrated?Top answer: No How Often Should I Have My Central Air Conditioner Serviced?Top answer: Every year Can I have central air if I have baseboard heat?Top answer: In most cases Do central air conditioners need to be covered in the winter?Top answer: No Can central air run on natural gas?Top answer: In some cases