Thermostat and Furnace Compatibility

Electric Heat and Cooling Systems - Low or High Voltage

Condensing Unit

Type: Electric Air Conditioning
Number of Thermostat Wires: 4 or 5
Voltage: 24 Volts AC
System Attributes: Outdoor condensing unit; cooling coils in furnace ductwork

Type: Electric Baseboard Heat
Number of Thermostat Wires: 2 or 4
Voltage: 120 Volts AC or 240 Volts AC
System Attributes: Localized heating with line voltage thermostat in each room

• Furnace and Thermostat Compatibility - Introduction
• Type of Systems - Millivoltage
• Type of Systems - Low Voltage
• Type of Systems - Line Voltage
• What to Look For When Identifying Your Furnace and Thermostat
• Gas Furnace System - Millivoltage
• Gas Furnace Systems - Low Voltage
• Boiler and Oil Fired Systems
• Electric Heat and Cooling Systems - Low or High Voltage
• Heat Pump Systems