What is Dual Fuel in the US?

The Answer Guide

What is Dual Fuel Heating?

Does it save energy?...
Does it make my home more comfortable?...
Is it more expensive?

Dual fuel heating involves the combination of a fossil fuel combustion heating system, such as a gas, oil, or propane furnace with an electric heat pump.

Because the technology for each fuel operates most efficiently during differing weather conditions, a dual fuel heating system maximizes efficiency, cuts heating bills, and minimizes environmental impact.

More important to many, dual fuel systems are more comfortable.

A Few Facts

  • The temperature of the air supplied by furnaces to the living space is typically 135°F. Most homeowners find the warmer air preferable when outside temperatures are freezing.
  • The temperature of the air supplied by a heat pump is typically 105°F. Most homeowners find the mellow temperature from a heat pump is preferable when outside temperatures are chilly, but not freezing.
  • The physical “balance point” of a heat pump is the temperature where a heat pump can no longer maintain the thermostat’s temperature setting. Usually, this is 25°F to 30°F. The economic balance point, when a furnace becomes more economic to operate than a heat pump is typically 30°F to 40°F.

How does Dual Fuel work?
In a dual fuel heating system, a furnace is used with an electric heat pump for heating. Heat pumps will heat and cool your home very efficiently. In fact, heat pumps are usually the most economic form of heating during cool to chilly weather.

Even when it feels cold outside, there is heat in the air, which the heat pump extracts and literally pumps it inside of your home. When the temperature outside drops below an economic balance point where it becomes more efficient to heat with gas, oil, or propane, the system switches to your furnace. Without a fossil fuel heat source, the heating system would use expensive electric resistance heat when the outside temperature dropped below the heat pump’s physical balance point.

How much does it cost and how much can I save?
A dual fuel heating system’s equipment and installation costs are slightly higher. After all, two heating systems using two different fuel sources are required. The cost will vary based on the size and heating load of your home, but is usually modest and will be repaid through utility savings. Depending on current utility rates, dual fuel systems typically cut utility expenses by 10%, vis-à-vis conventional systems. Of course, even greater savings are possible with the selection of higher efficiency heating and cooling equipment.

Will comfort improve?
Yes! Dual fuel systems offer the best of all worlds. During mild to chilly weather, homes are warmed with the steady, mellow heat of a heat pump, rather than intermittent blasts of high temperature air. When it’s freezing outside and a heat pump’s lower temperature feels drafty to some people, the system switches to the fossil fuel furnace with its warmer air. Each heating system is used when it’s most comfortable and most economic.

© 2005 Service Roundtable