Thursday, 28 March 2013

How does a gas furnace work?

A gas furnace is an extremely important and useful appliance for people living in cold regions. Also known as a home furnace, it converts gas to heat and is used to keep the circulation of indoor air warm and comfortable for living conditions. As an environmentally friendly option to preserve natural resources like wood, coal and oil to heat homes, natural gas is used in recent times. Some furnaces operate at 95% efficiency which simply means that what you pay for energy is converted into heat for your home’s indoors.

Before going on to understand how a gas furnace works, take some time to know the parts of a furnace. A home furnace is divided into three parts. The first part consists of the burner, heat exchanger, vent and draft inducer. The second is made up of safety devices and controls. The third consists of the blower and air movement. All these parts work in unison to keep the furnace running efficiently.

How does it work?

A gas furnace is a forced home air heating system that reacts when the indoor air temperature drops below the programmed setting on a thermostat. The heart of your home furnace is the burner controlled by a thermostat. When the temperature indoors falls below a certain point, the thermostat alerts the furnace which combines air and fuel and the mixture gets ignited by an electronic igniter.The combusted, hot gas begins to rise through the heat exchanger situated above the burner and heats the air which is circulated throughout the house. The remaining exhaust exits the gas furnace from a vent, which is let outside the house. The whole heating process starts at the heart of the system, which is the furnace controlled by the thermostat. Some furnaces come with two or more burners where huge volumes of air are heated for distribution.Meanwhile, an electric fan situated inside the furnace pulls in fresh air which comes through a flat, large grill located in the floor, wall or ceiling of the house. Before the fresh air reaches the furnace, it must filtered properly of dust and other particulate matter.If the cold air is not properly cleaned then it can have an adverse effect on its operation. You need to replace furnace filters every month and also keep the duct vents clean to provide maximum working efficiency and heat to your home. The filtered air passes into an enclosed space known as the plenum which is located opposite to the heat exchanger.The exchanger then heats the air very quickly which comes from the plenum as a result of high pressure. The hot air is passed out of the furnace and through the ductwork into your home’s indoor spaces. 

The ignited gases that are used to create the heat are vented through a shaft in the wall or roof. However in some furnace installations, a humidifier is added near the place where the intake duct is located so that the drying out of heated air can be mitigated. Humidifiers are directly connected to the water line by a tiny copper pipe.Another pipe is also used to drain away the condensation created from the process. Till the temperature inside reaches a specific point, the process is repeated again and again. Only after a certain level, the thermostat stops the furnace from the heating process.The size of the FurnaceIt is important to consider the size of the furnace before installation. The size of the gas furnace should match the size of the indoor spaces meant for heating.If the furnace is too large, it will off repeatedly and short-cycle, which in turn can lead to wear and tear on internal components and spikes in electricity.If the furnace is too small, it will constantly run in cold weather, which will take more energy to warm indoor spaces and therefore increase electricity usage.To determine what furnace size to purchase, take important points into consideration like your home’s total area for heating and type of insulation used. A well-insulated home goes a long way in keeping your furnace running efficiently and cut back on energy bills every month.

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