Not only will you have lower utility bills, but the comfort and quiet operation of a new system will surprise you. The contractor should install a computerized thermostat with it. This thermostat, coupled with the electronic controls in the new furnace, will maintain even room temperatures. These models are very efficient and so little heat is lost in the flue gases that a chimney is not needed. With no need for a new chimney liner, a condensing furnace is often cheaper to install than a less-efficient model.
Some models also offer sealed combustion for better efficiency.
The combustion air is drawn in from outdoors through another plastic pipe instead of being drawn from inside your house. Being sealed, there are fewer indoor drafts, less noise and less chance of hazardous backdrafting. This type of blower is needed if you want the best central air-conditioning too. In all but the coldest weather, the gas burners operate at a low heat level. The blower also runs slower and quieter at this low level.