Property owners usually use furnaces to heat their homes. You can choose between either an upflow furnace or a downflow furnace. Upflow furnaces are usually preferable, but some property owners do not have homes that are suitable for upflow furnaces. Both furnaces have some benefits and downsides.
An upflow furnace takes air from the bottom of the furnace, heats the air and expel sthe air from the top of the furnace. A downflow furnace does the opposite, taking air from the top, heating it and expelling it from the bottom. A property owner with an upflow furnace must place that furnace in the basement of the property so that the heat can efficiently rise to the upper levels of the property. A downflow furnace should be placed in the attic, releasing heated air to the lower areas of the property. Placing a furnace in the wrong spot can cause the furnace to waste energy by unnecessarily heating air, creating a larger energy bill. Upflow furnaces are normally more efficient because heat tends to rise, while downflow furnaces have to counter this natural tendency. However, some property owners do not have basements where they can place their upflow furnaces. Since heat rises, property owners lose a lot of heat through the attic to the outside no matter what they do, so downflow furnaces are rarely if ever more efficient than upflow furnaces.
Property owners usually prefer heat that rises from the floor than heat that descends from the ceiling. Rising heat warms the feet of the occupants, while descending heat heats heads and upper extremities first, which can be uncomfortable.
Since upflow furnaces are more energy efficient than downflow furnaces, upflow furnaces more often qualify for a tax credit.
Downflow furnaces use a system of ductwork to direct the heat downward where property owners want it. These furnaces can sometimes give homeowners more control over where the heated air flows by choosing where the vents go in the home -- and which ones are open or closed.
Cool air falls, making the recirculation of air easier for upflow furnaces. Furnaces need to take cold air and circulate it through the furnace, not only to create more hot air but to also eliminate the cold air.
In the upflow furnace, the basement may be colder than it would be with a downflow furnace, since the heat will mostly rise and will not warm up the air closer to the ground.