Q&A: What to look for in a new heating or cooling system.

What should I look for in a new furnace?

The three most important factors to evaluate when you’re considering purchasing a new furnace are: (1) quality; (2) efficiency; and (3) comfort features.

Quality

When you buy a new car, the quality of it helps determine how well it will perform and for how long. A furnace is really no different. 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 on random samples. Plus, 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: contact your local Carrier dealer for details.

For more information on quality and reliability, go to the Resource Center.

Efficiency

A furnace’s efficiency rating, or AFUE (Annual Fuel Utilization Efficiency), tells you how efficiently the furnace uses fuel (gas or oil). In general, the higher the efficiency, the less fuel the furnace will use to heat your home. For more details on AFUE, go to How can I compare the performance of heating and cooling products?

In 1992, the government established a minimum AFUE rating for furnaces installed in new homes at 78%. In contrast, many furnaces manufactured before 1992 had AFUE ratings as low as 60%.

Mid-efficiency furnaces, also known as non-condensing or induced draft furnaces, offer efficiencies from 78% to about 80%. High-efficiency furnaces, also called condensing or sealed combustion furnaces, offer AFUE ratings from 80% to about 96%.

Usually, the higher the efficiency, the more expensive 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.

Comfort Features

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 home’s 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 Carrier’s 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.

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