The answer to 'how much to fix thermostat' is that the cost can vary significantly depending on several factors. Generally, the cost to repair a thermostat can range from $50 to $300 or more. The exact price will depend on the type of thermostat, the complexity of the repair, and whether you need to replace the entire unit.
Factors that can affect the cost include the age and model of the thermostat, the accessibility of the wiring, and whether any additional components like the HVAC system need to be serviced. Simple repairs like replacing batteries or a faulty switch may be on the lower end, while more complex issues like a faulty control board or sensor may be on the higher end.