What wire should you use for your new home to ensure that it will work with the nest thermostat, ecobee thermostats or other smart thermostats? If you are wiring a new home you should always use at least 5 wires if you have a standard HVAC system and 8 wires if you have a heat pump or multi stage heating and cooling. Smart thermostats like the nest thermostat should be wired with 5 wires to ensure that they have constant power to provide the best connection and best thermostat functionality. If you are wiring a new home and your HVAC contractor or Electrician is unsure of how many wires to use, make sure you use the 8 strand wire we recommend in our post to ensure your new home is compatible with a smart thermostat.