Every year, homeowners across the country start an annual ritual as the temperatures start to drop. Closing storm windows, checking insulation, filling propane tanks, and even gathering firewood. We spend a lot of time and money, all in the name of warmth and comfort. But when the time comes to set that thermostat, do you really understand how your home is being heated? Knowing the details of how a furnace may seem unimportant. However, with just a little bit of information, you can save a ton of money and time by keeping your furnace up and running effectively.
Where It All Begins
When you turn up the thermostat in the winter, how does your furnace know? Well, the thermostat is directly connected to your furnace. When the temperature drops below the designated room temperature, a sensor sends an electronic message to the furnace to cut on. The furnace begins heating up and replenishes the lost heat in the controlled space. As soon as the designated temperature has been reached, the sensor terminates the signal, and the furnace shuts off.
This is a very simplistic explanation of how a furnace heats your home during the winter. There are, in fact, quite a few factors that affect the efficiency and performance of your furnace. Factors ranging from fuel sources and efficiency ratings to zoning and supplementary heaters have a great impact on how your furnace operates. This article will look at the basic function and operation of a furnace and the home’s HVAC system.
The first factor in how your furnace heats your home is the fuel source. Furnaces have to have some sort of fuel to burn to create heat. In some cases, furnaces use electricity to run. In this system, electricity heats metal coils inside the heat exchanger of the furnace. The coils become extremely hot and fill the cabinet with hot air. As the air becomes hot, a blower engages and sends the heat through the ductwork. There are no combustion products to vent away from the home, nor are there any clearance restrictions for installation.
In many cases, furnaces use combustible fuel to create heat. Common combustible fuel sources include gas, propane, and oil. The fuel is piped into the furnace from a tank, hopefully outside of the building. Simultaneously, combustible air must be drawn into the furnace as well to provide the oxygen for combustion. Depending on the system, this air is taken from outside or an adequately sized area in the home.
The mix of gas and oxygen feeds the flame as it also heats metal coils or panels in the furnace. These coils heat the air that is passing through by the use of a blower or gravity, depending on the system. The difference is that the combustible product must be delivered safely from the house. This happens through direct piping to the outside or through venting to a chimney or flue.
The heat exchanger is the component of your furnace that creates heat and passes it through your furnace. A mix of fuel and combustion air enters the heat exchanger. The flames from the burners feed off the heat and air and heat sets of coils. Circulated air then crosses the coils, either by the blower or natural draft. Products of combustion, like carbon monoxide, leave the burners and are vented away from the home.
The first element in the distribution of heat in your home is the blower. The blower consists of a fan that sits adjacent to the heat exchanger. Depending on the style of the furnace, the blower either pushes or pulls air across the heat exchanger. The fan can be adjusted to different speeds in most modern models to help regulate the consistency of heat distribution in the home. However, there are a few different types of forced air distribution.
Low-efficiency models are typically older models. They have no blower or open burners and rely on the natural draft of the home to circulate air. Mid-efficiency models usually have an induced draft across the burners, meaning the fan pulls the air across. The combustion air is usually from an open space inside the home. High-efficiency models are usually sealed systems. The fan pushes air across the burner. The combustion air is piped in from outside, and the combustion products are piped outside.
The next step in the process of heating your home is ductwork. The heat leaves the heat exchanger and travels through the ducts. The ductwork travels throughout the home and distributes heat through vents called registers. In a modern home, each room should have at least one register. Many modern homes will have numerous registers in a room, hallway, or open space.
Ducts travel throughout the wall cavities and unfinished spaces of the home. Each branch has been set to certain dimensions to help heat reach the rooms farthest from the furnace. Some ducts have baffles that can adjust the amount of air traveling through a section of ductwork. This allows a technician to adjust the airflow during different seasons, if necessary.
Equally important in the role of heating the home is the return ductwork. This separate set of ducts brings the cooled air back to the heat exchanger to be heated and pushed through the supply ducts again. The return system is also where you place air filters to help protect the furnace and raise the air quality in the home. The return and filter system is most efficient when a home is reasonably sealed and insulated. Cross breezes and drafty rooms can throw off the system’s circulation and lower its performance. Drafts and air leaks can also introduce debris into the air’s circulation, shortening the lifespan of your furnace.
Checks and Balances
As you can see, your furnace is part of a larger system. This system was not just haphazardly thrown together. Every home has different heating needs and requirements. Some homes have a furnace in the basement or crawl space, while others have one in the attic. Larger homes have multiple furnaces heating separate zones in tandem.
This system requires occasional inspections and maintenance to make sure the distribution of heat is balanced, the filters are clean, and the furnace is running at optimal performance. Furnaces also have a lifespan, depending on age, style, and model. Pushing a furnace too far past its lifespan can cause serious problems in the home.
If you are having issues with your home’s furnace or air conditioning, or if you just have more questions, call White Mechanical, Inc. for an experienced, professional technician. We have been providing excellent service to the residents of Orange County for over twenty years. We also offer commercial services as well. Our professional team of technicians can install quality equipment or repair your current system at a reasonable cost. Our residential and commercial services include duct cleaning, duct upgrades, heating and cooling repairs, HVAC installation and maintenance, ventilation, and filtration. So contact White Mechanical, Inc. today and schedule an appointment.