Gas and oil furnaces provide warm, even heat throughout your home by circulating heated air through ducts. This section will provide insight on four main furnace topics:
- How They Work
- Energy Efficiency
How They Work
The heat is created by burning gas or oil inside your furnace. Hot gases that are created pass through curved metal tubing called a heat exchanger and then out of your home through a metal or plastic vent pipe. At the same time, the air that circulates through your home passes over the outside of the heat exchanger and takes on the heat from the hot metal. The warm air is then circulated through your home.
Purchasing a brand name that has a reputation for quality and reliability can save you headaches and extra expense down the road.
New Carrier furnaces, for example, undergo a rigorous series of quality tests and checks, during production, with many of the tests being performed on every unit - not just random samples.
We back every furnace in writing, with a 20-year or more limited warranty on the heat exchanger (the heart of the furnace) and a one-year limited warranty on the entire unit. Extended warranties are also available.
Some mid- and high-efficiency furnaces offer additional features that provide greater comfort, as well as additional energy savings.
Two-speed furnaces can run on low speed up to 90% of the time, so they operate more quietly and run for longer periods of time than single-speed furnaces. Longer operating periods translate into fewer on/off cycles, fewer drafts and much smaller temperature swings -- only one or two degrees instead of the four-degree swings common with single-speed furnaces. Plus, better air circulation helps prevent air "stratification" warm air rising to the ceiling and cold air settling on the floor. In short, you get consistent, even heat throughout your home.
Variable-capacity furnaces provide the ultimate combination of comfort, efficiency and quiet performance. In addition to the benefits of two-speed furnaces, they offer "smart" motors than can monitor your homes comfort needs and automatically adjust the volume and speed of air to provide the most efficient heating or cooling. They offer added electrical efficiency as well: the "smart" fan motors on Carriers variable-capacity furnaces use less electricity than a 100-watt light bulb. They operate so efficiently that they can actually increase the efficiency rating of your central air conditioning system and offer you added energy savings when you use continuous fan operation in any season.
A furnace's efficiency rating, or AFUE (Annual Fuel Utilization Efficiency), tells you how efficiently the furnace uses fuel (gas or oil). In general, higher efficiency furnaces mean lower monthly operating costs for heating.
The government-mandated minimum AFUE rating for furnaces installed in new homes is 78%. In contrast, many furnaces manufactured before 1992 had AFUE ratings as low as 60%.
Higher efficiency furnaces offering AFUE ratings of 80%, 90%, or up to 96% are also available to help reduce monthly heating costs.
Usually, the higher the efficiency, the more expensive the inital cost of the furnace. If you live in a cold climate, you will probably see the higher cost of a high-efficiency furnace paid back through lower utility bills in a few short years. Your dealer can use heating data from your area to help you determine about how long it would take you to recover the additional cost in energy savings. Of course, after the payback, you continue to save on your energy bills for the life of the system.