Electric heating is the only heat produced almost as fast as the thermostat calls for it. It is nearly instantaneous because there are no heat exchangers to warm up. The heating elements start producing heat the moment the thermostat calls for it. Unlike electric base- board heating systems, electric furnaces are designed to provide the same heating/cooling advantages as gas or oil furnaces.
Because there is no flame with electric heat, there is no need to vent smoke or flue gases to the outside. Furthermore, there is no chimney loss with electric heat. It is 100 percent efficient, compared with the 60 to 95 percent efficiency of furnaces using other fuels.
Electric furnaces are available in upflow, downflow, or horizontalflow models and in a wide range of sizes. For example, Carrier electric furnaces are available in 15 standard models from 5 to 35 kW in 5-kW increments. Other manufacturers offer a similar range of models (Figures 14-1 and 14-2).
An electric furnace should be listed by Underwriters Laboratories, Inc. (UL) for construction and operating safety. Furnaces approved by the agency are marked UL Approved.
Electric furnaces should be installed in accordance with local codes and regulations, the National Electrical Code, and recommendations made by the National Fire Protection Association.
Electrical Power Supply
Contact the local power company and make certain adequate electrical service is available for the furnace load plus all other appliances that will be on the line.
Check the National Electrical Code and the local code requirements. All wiring (including sizing) must comply with the requirements of these codes. When there is any conflict, the local codes and regulations take precedence. The manufacturer’s requirements are also important. For example, Janitrol discourages the use of aluminum wire, although it is acceptable to the National Electrical Code. Use of aluminum wire in this case could jeopardize the furnace warranty.
Be sure to consult the manufacturer’s wiring diagrams for electrical power requirements. Read the instructions carefully, and be sure you understand them thoroughly before you begin work.
