Have you ever heard of a hybrid heating system? Also known as a dual-fuel system, learn how it can save on heating costs over the long-term and how it works.
If you’re building a new home or remodeling your existing one, you may think you have only two options when it comes to heating systems. One is a combustion furnace that burns natural gas, propane or heating oil. The other is a heat pump system. But you also have a third option — a hybrid heating system. Learn the benefits and shortcomings of each to assist you in making your choice.
Combustion Furnace
For years, this heating technology has been the most prevalent in American homes. Furthermore, it is likely to remain so, given the increase in domestic production of both natural gas and heating oil.
In a combustion furnace, gas or oil fuel is sparked into flames by a pilot light or electronic ignition. Burners keep the fuel flaming in a combustion chamber, and the heated air is blown through your house via a network of ducts. Eventually, the air cools and is drawn from the rooms of your home through an air return and routed back to the furnace where it’s heated again. Combustion gases, including carbon monoxide, are routed out of your home by a flue pipe and chimney.
Combustion furnaces can be plagued by inefficiencies though. How well a furnace converts fuel into heat is reflected in its annual fuel-utilization-efficiency (AFUE) rating. The higher the AFUE percentage, the better the furnace is able to use all of the heat generated by the fuel it burns. As technology has improved, so has the efficiency of combustion furnaces. According to Consumer Reports magazine, gas furnaces made in the 1970s typically had an AFUE of about 65 percent. The lowest efficiency allowed by law today is 78 percent, and some of the newest models have ratings up to 97 percent. The higher the AFUE, however, the more costly the furnace.
Finally, if propane gas is your only source of combustion, that can increase heating costs as propane is about a third more expensive than natural gas.
Heat Pump
An air-source heat pump uses the unique heat exchange capabilities of a refrigerant to move heat energy from one place to another. Even when the weather is cool, ambient heat persists in the atmosphere. The refrigerant flowing through a heat pump extracts this heat from the outside air and transfers it to an air conditioning coil in the furnace. The furnace fan then blows air over the coil, sending warm air throughout the house via its duct system.
A great advantage of a heat pump is that it saves energy. Transferring heat by these means is more energy-efficient than burning fuel to produce heat. Working at peak efficiency, a heat pump can transfer 300 percent more energy than it consumes, compared to 97 percent for the latest combustion furnaces.
The heat pump’s greatest shortcoming is that while it provides sufficient heat in areas with brief and mild winters, the system struggles to extract heat from the outside air, when the temperature falls below freezing, potentially leaving your house chilly and uncomfortable.
Hybrid Heat System
The third option is a hybrid heat system, sometimes called a dual-fuel system. In a hybrid system, an air-source heat pump is backed up by an auxiliary combustion furnace. When temperatures plunge below a certain level, the combustion furnace kicks in, keeping your house warm in even the coldest weather.
You can program the temperature at which the system switches from the air-source heat pump to combustion — or if you prefer, you can make the switch manually.
Like hybrid cars, hybrid heating systems cost more than their conventional counterparts. They promise long-term savings by reducing your monthly energy expenditures. Best estimates suggest that a hybrid heating system can save a homeowner between 30 and 50 percent in energy costs over the course of a year. Many hybrid systems pay for themselves within three to five years.
In addition to lowering your utility bills, use of a hybrid heating system may qualify you for a tax credit or rebate, either from the federal government or your state. Ask your utility company and HVAC contractor about incentives that may be available in your area.
However you choose to keep your home warm and cozy, you'll also want to protect the investment you've made in your heating system. That means performing the manufacturer's recommended preventive maintenance, regularly changing your filters and otherwise taking care of your system and its key components. To help control the costs associated with the repair and replacement of your home's HVAC system, consider purchasing an American Home Shield® home warranty. Our plans can help you protect your home and your household budget.
