Furnaces—Gas and OilIn our area, the furnace is the most important appliance in a home. We visit the refrigerator many times daily, and a hot shower is a daily ritual for most of us, so we don't think about the furnace sitting in the basement, faithfully keeping us comfortable through the colder times of the year. Routine servicing will help ensure it continues to do so.
Your furnace is also likely to be the appliance that consumes the most energy in your home. Improvements in recent years have reduced operating costs through more efficient motors and more effectively extracting heat from fuel. So if you're looking to cut your energy bills—or just to cut your carbon footprint—the appliance that will provide the biggest impact is probably your furnace.
A typical high-efficiency gas furnace today uses 95% of the heat per unit of fuel. Compare that to an 80% efficiency gas furnace (typical of 1990) or a 70% unit (typical of 1980), and you can expect to save 15-25% off your energy bill.
New technology also provides a more comfortable heat by adjusting heat output to maintain a stable temperature, rather than cycling fully on and fully off as in the past. Instead of having your home temperature repeatedly cycle up and down by a few degrees, a modern furnace equipped with a digital thermostat will hold the temperature stable with less than a degree of fluctuation.
Lastly, the newest generation of furnaces use "sealed combustion". Older units suck in air from your house, burn it, and send it up your chimney—creating drafts as they pull in air around windows and doors to replace that which is lost. Modern furnaces have an air intake that uses outside air for combustion, reducing draftiness, but also having an important effect on humidity—as we all know, "It's not the heat, it's the humidity." Cold air carries less moisture than warm, so as an older furnace operates it dries out the air in your house. Coupled with a humidifier, sealed combustion can help your house stay comfortably humid— making it feel warmer at the same temperature, or equally warm at a lower temperature.