It is not necessary to have an electrician to install a thermostat. Thermostats can be easily installed by following the manufacturer's instructions. However, if you are not comfortable with installing the thermostat yourself, it is advised to hire a professional electrician.

It depends on the thermostat. If it's a programmable thermostat, then you might need an electrician to install it, but most regular thermostats don't require any special installation skills.