| Do you know how energy efficient your furnace | | | | for extra efficiency, and with sealed combustion |
| is? Most homeowners don't really know. A central | | | | chambers, attain 90%-97% AFUE. |
| heating furnace's efficiency is measured in terms | | | | Don't worry, you aren't stuck with old money-pit |
| of annual fuel utilization efficiency (AFUE). The U. | | | | furnace forever. Furnaces can be retrofitted to |
| S. Federal Trade Commission forces | | | | raise their efficiency. Upgrades improve both the |
| manufacturers of new furnaces or boilers to | | | | safety and efficiency of otherwise sound, older |
| display their AFUE on their product so that | | | | systems. The costs of retrofits should be |
| consumers may compare heating efficiencies of | | | | carefully weighed against the cost of a new |
| various models. | | | | furnace, especially if replacement is likely within a |
| AFUE expresses how efficient the appliance is in | | | | few years or if you wish to switch to a different |
| the energy in its fuel over the course of a typical | | | | system for other reasons, like adding air |
| year. To be more precise, AFUE is the ratio of | | | | conditioning or going all-gas from electric power. |
| heat output of the furnace compared to the total | | | | Vintage model furnaces with a continuous pilot |
| energy consumed by a furnace. An AFUE of 90% | | | | light can be retrofitted with intermittent ignition |
| means that 90% of the energy in the fuel | | | | devices. These are difficult to install, however, and |
| becomes heat for the home and the other 10% | | | | only should be installed by certified professionals. |
| escapes up the chimney and elsewhere. AFUE | | | | Costing about $250, they characteristically have a |
| doesn't include the heat losses of the duct | | | | payback period of less than 10 years. Even |
| system or piping, which can be as much as 35% | | | | though intermittent ignition devices can save you |
| of the energy for output of the furnace when | | | | some in fuel costs, they are not always that cost |
| ducts are located in the attic. | | | | effective when installed on old equipment. Turning |
| You can figure a system's efficiency not only by | | | | off a furnace's pilot light in the spring and turning it |
| its AFUE but also by its equipment features and | | | | back on again in the fall can usually save the |
| type. For example, older, low-efficiency heating | | | | same amount of money as you would with one |
| systems have a continuous pilot light, heavy heat | | | | of these devices. Not all continuous pilot light |
| exchangers and an AFUE of around 68%-72%. | | | | furnaces can accommodate this solution, though, |
| Newer, high-efficiency heating systems feature | | | | so check with your furnace manual or heating |
| condensing flue gases in a second heat exchanger | | | | contractor first. |