According to Energy.gov, a high-efficiency furnace works by condensing gas in another heat exchanger, yielding a more efficient system. A furnace with high efficiency also has sealed combustion for better performance, and a system of this quality has a range of 90 to 98.5 percent Annual Fuel Utilization Efficiency (AFUE).Know More
HomeTips.com notes that the AFUE is measured in terms of heat consumption. A high-efficiency furnace with a 96-percent AFUE means that it is transforming air into 96-percent consumable heat. When it comes to comparison between an oil and electric furnace, one notable difference is that the electric option does not contain a flue, but since electricity is more expensive, many choose a fossil fuel-based furnace.
According to Dr. Energy Saver, high-efficiency oil furnaces tend to have sealed combustion systems of the condensing variety. It works by using a plastic tube that carries combustion air to the chamber. A secondary exhaust process, known as the condensing cycle, cools any gases. As a result, no chimney is necessary. A high-performance system typically operates at 96 percent AFUE, Dr. Energy Saver notes. An older furnace can operate at only 75 to 80 percent AFUE. Highly efficient oil furnaces that have a 96-percent AFUE rate decreases heating oil payments each year by hundreds of dollars.Learn more about Heating & Cooling
A gas furnace should be replaced when the furnace begins making weird noises, reaches a certain age or displays decreased efficiency and after the burner flame turns yellow. Generally, a gas furnace should be replaced when the furnace costs over $500 to repair or is more than 15 years old.Full Answer >
A furnace's gas valve controls gas flow to provide a steady stream of gas while controlling pressure. The valve also includes a safety feature that cuts off the gas supply if a certain temperature is not reached to prevent leaks.Full Answer >
A gas furnace consists of two parts, an outdoor air conditioning unit and indoor furnace that work together to draw in, heat and circulate winter air and cool, then circulate, warm summer air. These two units contain components including a burn, flue and heat exchanger that contribute to making the process complete.Full Answer >
According to HowStuffWorks, the thermocouple in a gas furnace uses two dissimilar metals that produce an electric current when heated in order to power an electromagnet that opens a valve allowing gas to reach the furnace. If the pilot light goes out, the thermocouple cools and no longer produces the current, so the electromagnet releases the valve to stop the gas flow.Full Answer >