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If you have a heating system in your home, you probably are using one equipped with one of the most common furnaces around; gas or electricity. Modern furnaces have come a long way from the early versions that used wood and coal. It is therefore expected that most people will always ask, "How does a furnace work in a house?"


How does a Furnace Work in a House?

Understanding how a furnace works also helps you in operating and maintaining your unit. In case of any hiccup, it becomes easy to know where to look and also troubleshoot the whole setup. HVAC professionals suggests that having this knowledge also helps when it comes to picking among the heating systems to tell which will better suit your house and save energy.


The basis of all the furnaces is forced air heating, which means that the heated furnace transfers heat to the air which is then sent through the duct system of your house by the blower fans and distributed all around the house. You do not have to worry about space and how you will fit two duct systems in the house because the furnace heating systems easily share the same duct work with the home's air conditioning unit. This is the brevity of how a furnace works. To fully understand the details, you need to know the various parts of the furnace heating system and their roles.

How Does a Furnace Work in a House

Parts of a Furnace

1. Thermostat - All furnace unit systems contain a thermostat. Its purpose is to detect the temperature levels in the house. It is usually preset to the appropriate degrees. Should the temperatures in the house fall below the set number, the thermostat activates the furnace by sending a signal which opens up the gas valve and a device called a pilot light ignites the furnace.

2. Burners - Gas powered burners are designed to maintain a constant even flame. They all have to be lit for the system to kick on since internal sensors usually shut down the mechanism if even one burner is not lit.

3. Heat Exchanger - Heat from the burners is directed to the heat exchanger which is what warms the air as it is more efficient compared to if it was up to the burners alone. If this component is not working, then you will not get warm air.

4. From the heat exchanger, the warm heat is blown through the ducts and across the whole house by the blower fans propelled by a motor. Once the desired temperature is reached, the thermostat sends a signal to shut down the entire mechanism.


In an electric furnace, the process is the same only a few different components are involved. In place of a pilot light, there is electronic ignition, and in place of gas burners and heat exchanger, we have conductive coils through which air passes through, and it gets heated up for distribution. 


The right furnace system will save you a lot of energy since much of the fuel burnt will be used up for heating the air with very little going to waste. You have to check for the Annual Fuel Utilization Efficiency when choosing a furnace.



Although furnaces and heaters keep you warm over the colder months, it's important to be aware of the safety precautions when it comes to heaters. The Consumer Product Safety Commission (CPSC) estimates that more than 25,000 residential fires and more than 300 deaths are caused each year by space heaters. More than 6,000 Americans receive hospital emergency room care annually for burn injuries associated with room heaters.


Knowing How A Furnace Works

How does a furnace work in a house? The answer lies in knowing the roles of the major parts of the system. You can split it into three to have controls which is the thermostat, the heat source like the burners and the distribution which are the duct and vents system.