The Tekmar Invita WiFi Thermostat makes upgrading easy by using the existing 2-wires from any living space to connect to an HVAC Interface Module in the mechanical room. It works with most types of heating and cooling systems including conventional, heat pump and dual fuel while offering fan, relative humidity and ventilation control. The Invita Connect app provides secure WiFi adjustment, and can send email notifications when there are problems with the HVAC system. The Invita WiFi Thermostat is available in both white and black finishes and offers a choice of five display screen color themes. Compatible with Alexa and the Google Assistant.