Dual Fuel Systems

Dual Fuel Systems

A heating system that uses both a gas furnace during extreme cold weather, and a more efficient heat pump in milder months. The benefit of these flexible fuel units is they use the least expensive energy source for heating, based on the outside temperature. Dual Fuel systems don’t run at the same time, either the heat pump OR furnace does the heating.

While dual fuel systems can be found in DFW, they are primarily designed for northern climates where winter temperatures are frequently below 35ºF.

A Heat Pump with Auxiliary Heat

A heat pump with auxiliary (electric) heat combines a heat pump with an air-handler. An air handler is not a furnace — it cannot produce heat unless heat-strips are added. Both the heat pump AND electric heat-strip run at the same time when the outside temp is too cold for the heat pump to create enough heat by itself.

This system is typically what is found in DFW.

NOTE: If you have a Heat Pump with Auxiliary Heat, be sure your thermostat is set to “Aux Heat” — not “Emergency Heat”.

“Aux Heat allows both the heat pump and heat-strips to run at the same time.

“Emergency Heat” shuts the heat pump off, and only electric heat is provided. This is a much more expensive way to generate heat and defeats the purpose of having a heat pump. The “Emergency Heat” setting is to be used only if the heat pump stops working.

How can I tell which type of system I have?

If you have a dual fuel system, the furnace will be likely be gas in DFW. There will have either a 6 inch gray pipe, or white plastic pipes coming from a furnace.

There are no vent pipes coming from an air-handler (it uses only electricity). There will be one large cable coming into the air handler. This is its electric supply.

One cable provides the electricity (see top left of the unit). A furnace will have either a gray pipe OR white plastic pipes coming from it. These pipes provide for the venting of the exhaust gases.

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If you need a/c or heating repair or a new system installation in the Dallas metro area, give us a call at 972-225-5257 or contact us online.
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