Smart thermostats are often promoted as an easy way to reduce household energy bills. They can learn your routine, adjust the temperature when you leave, provide reports about your heating and cooling use, and let you control your HVAC system from almost anywhere. Those capabilities sound impressive, but they leave many homeowners with an important question: can a smart thermostat genuinely save money, or is it mainly a convenient upgrade?The short answer is that smart thermostat savings are ...