What Is Forced-Air Heating? (2023 Guide)

There are several types of heating systems available, and choosing the right one for your home is an important decision. All home heating systems have the same goal: to transfer heat and maintain a comfortable temperature in your home. However, different systems work in different ways.

One popular option is forced-air heating. We’ll explore how this system works, its advantages and disadvantages, and what to consider when hiring a professional.

Forced-air heating is a central heating system that distributes heated air throughout your home using a blower via ducts and vents. Not all home heating systems use air to heat the house. For example, hydronic heating systems use water or steam to transfer heat from a boiler to the home through radiators or radiant heating.

The two most common heating systems that use forced-air distribution are furnaces and heat pumps. Furnaces heat air by burning fuel—natural gas, propane, oil, electricity—while heat pumps transfer heat from outside into the home. Both heat pumps and furnaces have pros and cons. The best system depends on your area’s climate.

Here’s how a forced-air heating system works using a gas furnace:

• Step 1: The thermostat signals the furnace to heat the home.
• Step 2: The furnace’s inducer motor kicks on to exhaust gasses from the previous cycle.
• Step 3: The pressure switch conducts a safety check.
• Step 4: A surface igniter, standing pilot, or spark ignition ignites. Electric systems use spark or surface ignitions while standing pilots burn continuously in gas furnaces. 
• Step 5: The heat exchanger heats the air in the plenum, a box that connects your HVAC system’s air handler to your ducts.
• Step 6: Blower fans force the heated air into the supply ducts. This also creates suction in the return ducts to pull recycled air into the system.
• Step 7: Air is pulled in through the air intake for replacement air. Otherwise, the furnace may draw air from the attic or crawlspace, reducing your home’s air quality.
• Step 8: The system shuts down when the home reaches the thermostat’s set temperature.

To better understand how a forced-air heating system works, you should know the essential parts and their importance. 

• Heat source: A forced-air system must have a source to draw heat from and distribute throughout the home. Forced-air systems use a furnace or heat pump as their heat source.
• Thermostat: Controls the temperature in the house and tells the heat source when to turn on and off.
• Supply duct: Distributes heat throughout the home.
• Return duct: Recycles air back to the heat source, helps maintain air circulation, and prevents hot and cold spots.
• Air plenum: A box that helps distribute heated air through your system’s ductwork.
• Heat exchanger: A metal shield located between the combustion chamber and blower that transfers heat from the source to unheated air.
• Blower fan: Forces the heated air through the ductwork and creates suction in the return ducts.
• Safety switches: Powers down the heat source if safe conditions aren’t met.
• Combustible fuel exhaust: Keeps combustion gasses out of the home.

Like all home systems, a forced-air system has pros and cons. Knowing its advantages and disadvantages will help you decide if it’s the right choice for your home.

Advantages of Forced-Air Heating:

• Heat distribution is almost instantaneous: Once the heat source kicks on, the home heats up quickly. The air is heated directly and then forced through the home’s ductwork.
• Heat sources are energy-efficient: Modern heating systems, such as an all-electric furnace and forced-air heating system, have an annual fuel utilization efficiency (AFUE) between 95% and 100% (according to Energy.gov). This means almost 100% of the fuel becomes heat for the home while 5% or less is lost. Homeowners can make even more upgrades to slash energy costs, such as adding a smart control for HVAC units.
• They’re cost-effective: Though expensive to install, a forced-air heating system can save homeowners up to $500 per year on their energy bills.
• They can last for decades: A furnace can last up to 30 years. Even after replacement, you can use the same duct and vent system to heat your home.
• Easy installation process: If you already have ductwork installed, adding a new heat source is a simple process.

Disadvantages of Forced-Air Heating:

• Creates carbon monoxide: Forced-air furnaces can leak carbon monoxide, which is a deadly gas.
• Maintenance is required: Because forced-air heating systems contain so many components, routine maintenance is required.
• It’s noisy: Forced-air heating can be noisier than other types of heating systems. 
• Ducts carry allergens and dust: If not cleaned and regularly maintained, dust and other allergens can collect in the ductwork and forced-air unit. The blower can push built-up contaminants into the home when the heat turns on.
• There may be inconsistent heating: The room’s size and location, and the location of the ductwork, may cause some areas of the home to be warmer than others.

Here are some tips for hiring a professional to install a forced-air heating system:

• Check the reviews for several local HVAC contractors and ask friends and family for recommendations.
• Look up the business on the Better Business Bureau (BBB) and read customer reviews.
• Contact multiple contractors and ask about their experience, availability, and rates.
• Ask about the installer’s experience with forced-air heating systems and their knowledge of the best HVAC brands.
• Check whether your HVAC contractor has the proper state licensing to work with forced-air heating systems.
• Get a written estimate and avoid companies that charge way less than their competitors.

Forced-air heating is one of the most common heating systems. Most forced-air systems have the same components, but different heat sources are available. Like most home systems, forced-air heating systems have their pros and cons. Understanding how they work and what to expect can help you decide if a forced-air system is right for your home. 

Contact a professional HVAC contractor if you have questions about specific forced-air unit brands or need help with your system.

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