Bob Boldt HVAC is your go-to source when you need a thermostat in Rosemount, MN. As the central controller of your home’s HVAC system, thermostats play a key role in your comfort and the efficiency of your equipment. As they age, however, they may malfunction or require recalibration to continue functioning well. Or, you might wish to install a state-of-the-art smart thermostat to give your HVAC system a modern makeover.