ThermaLink: A Multi-System Thermostat That Runs Itself. ThermaLink adapts to a building’s changing climate demands, offering full control of a heat pump’s heating and cooling functions while supporting reliable backup from existing line-voltage electric heaters. It allows buildings with existing electric heaters to upgrade to a heat pump system, retaining the original heaters as backup. It meets State Energy Code requirements by using automatic controls that only activate emergency electric heat if the heat pump cannot maintain the desired temperature. The standard kit includes a 7-day programmable thermostat, a 120/240-Volt 20A electric heat relay, and a 24-Volt HVAC relay. Optional wireless RF sensors can detect when someone is in the room or if a door or window is left open and adjust the temperature automatically. An outdoor sensor can be added to limit electric heat use when the heat pump can meet demand, and enable it when outdoor temperatures fall below the heat pump’s effective range. Plus, multiple rooms can connect to a wireless master switch, letting you adjust the whole building with one button.