It depends on the type of thermostat you are replacing. If you are looking to replace a mechanical thermostat, then any standard mechanical thermostat will work. If you are looking to replace a digital thermostat, then you need to make sure the replacement is compatible with your heating and cooling system. Most digital thermostats are compatible with most systems, but there are a few exceptions so it's best to check before purchasing.

It depends on the type of thermostat. If you are replacing a mechanical thermostat with a digital one, most likely you can. If you are replacing a digital thermostat with a mechanical one, you may not be able to because the wiring may be different. Check your owner's manual or contact the manufacturer of your current thermostat to see if it is compatible with the new model you are considering. You also need to make sure that the new model has all of the features that you want and that it is compatible with your heating and cooling system.