Heating

Gas or fuel burning furnaces all work on the same basic principle. The fuel is burned inside an enclosed metal container (commonly referred to as a fire box or a heat exchanger). The exhaust gases (including carbon monoxide) are vented to the exterior of the building. The burning of the fuel warms the heat exchanger. The heat exchanger, now hot, radiates the heat into the air in the living area. This heated air is circulated by gravity or pumped through the living area with a fan.
 

These will usually be found in older homes. They include floor and wall furnaces and some ducted furnaces that are generally in a basement. The term gravity referrers to the fact that the furnace has no blower to move the heated air around the room. They rely on the fact that heated (less dense) air rises and the cooler (more dense) air falls to circulate the heat. This is not a very efficient way to heat a house and generally will be used as a room heater.

Are not the best ways to heat your home and are expensive to operate. They can make your electric meter spin like a top. They work like those old bathroom electric coil heaters except that they are enclosed in a box with a blower forcing the cold air across them heating the air for the living area.

Radiant heating does not dehumidify the air, so in winter, room humidity is more ideal. Unlike forced hot air, radiant heat will not dry out breathing passages or furniture. With no fans or blowers, radiant is dust-free, so it's also cleaner. Virus particles, bacteria and pet dander fall to the floor instead of circulating constantly in the air, so your family will stay healthier in winter. Because radiant heating warms the occupants rather than the room, people find they are comfortable at temperature settings several degrees lower than with conventional heating systems. Lower temperature settings mean lower fuel costs. You can learn more about floor warming and floor heating in our article center.

Space heating energy costs account for roughly 25-30 percent of the total energy costs for a typical commercial building in the Eugene/Springfield area. High-efficiency boilers can reduce heating costs by 10 percent and in many cases by as much as 20 to 30 percent.

In fact, a boiler replacement that reduces gas consumption by 20 percent could save about five to 10 cents per square foot annually.

Boilers are also available in two efficiency ranges, which include 80 percent for standard conventional boilers and 90 percent or higher for energy-efficient condensing units.

The dividing line between these efficiency ranges is based on the boilers ability to withstand condensing flue gases. Condensing flue gases, which occur in high-efficiency boilers, do require a special design for considerations to tolerate the corrosive effects of the condensate. Boiler efficiency is defined as how much of the heating value of the fuel is being converted to useful heat.

Condensing boilers absorb more heat from combustion gases, allowing the water vapor to condense and therefore providing increased efficiency. Any hydrocarbon fuel burned in a boiler, whether it is propane, natural gas, or fuel oil, produces water vapor during the combustion process.

Conventional boilers are non-condensing boilers with materials that cannot tolerate the corrosive properties of condensing flue or stack gases. Conventional boilers operate around 80 percent efficiency, compared to over 90 percent efficiency for condensing efficient boilers. Other factors also influence boiler efficiency, including boiler shell losses, piping losses, and cycling losses.

Boilers use water to absorb heat from a burned fuel/air mixture. Boilers can produce steam or hot water. The two most common types of boilers are fire tube and water tube.

Fire tube boilers typically consist of a series of straight tubes that are housed inside a water-filled outer shell. As hot gas flows through the tubes it heats the water that surrounds the tubes.

Water tube boilers are designed to circulate hot combustion gases around the outside of a large number of water-filled tubes. Newer boilers have tubes with complex and diverse bends and fins to maximize the heat transfer area.

Because the water/steam pressure is confined inside the tubes, water tube boilers can be fabricated in larger capacities than fire tube boilers and are often preferred for higher-pressure steam applications.