Furnace vs. Air Handler: Complete List Of Differences Between Them

Whether you’re a newbie in the world of HVAC heating and cooling equipment or a pro who’s been there, done that, and seen it all, it is not a matter of surprise if you’re having somewhat of a problem distinguishing between two specific kinds of heating systems: the air handler and the furnace.

Often baffling the minds of most people out there, these two devices seem to have a similar role to execute, so it often leads to confusion when customers go through different models of air handlers and furnaces without knowing which one they should buy. It also doesn’t help that both air handlers and furnaces display a similarity in appearance while working towards the apparently same goal of producing heat and warming up an area.

However, there are certain myths surrounding these units that ought to be dispelled so as to give you a more precise idea of which model to pick in accordance with what benefits you the most.

In fact, we’ll start off by eliminating some doubts for you right away. Take, for instance, the manner of operation of both units. Where an air handler is an all-electric system that runs on your home’s circuit, a gas furnace functions on the basis of using gas or propane to heat your home. Another example of such a difference is that an air handler often has an additional source, such as a heat pump, which aids in its generation of heat, whereas a furnace generates heat on its own and moves it around as well.

This is neither where the differences end nor where the similarities start.

If you want to truly be able to distinguish between the two units and be able to judge for yourself which one would be more resourceful for you, we have provided below information on both devices, along with a list of differences and similarities between them.

Air Handler Explained: What is it, and What does it do? - Differences Between Furnaces and Air Handlers

If you’ve heard of forced air systems, you will be able to understand air handlers better. For your reference, a forced-air system is one in which a blower or a fan regulates air throughout your home’s ductwork and moves it around.

The blower, then, is largely responsible for the exchange of hot and cold air in your house. And so, the origin of the name “air handler" is the handling of the movement of air by the blower, which is a crucial part of the system.

An air handler is a device that provides air conditioning and heating in a commercial or institutional building. It consists of a number of components, including a condenser, compressor, fan, heat pump, and other hardware, as well as specialized software. An air handler's primary function is to move air through the building, distributing cooling or heating where it is needed most.

As mentioned, the air handler makes good use of a heat pump, which is also involved in the ductwork and ventilation system of your home. However, the heat pump is the component doing most of the work, as it does the primary task of heating the air. It is then that the air is taken over by the blower and moved through the different ducts.

With regards to the inner workings of the heat pump, you can equate it to your knowledge of the operation of a refrigerator. In low temperatures, warm air is absorbed from outside and circulated indoors through the air handler.

A similar process is undertaken during high summer temperatures. The heat pump is also electric, giving it a distinctive quality compared to the gas furnace. Electric heat pumps work by using the thermal energy of water to heat air. The heat pump extracts thermal energy from the water and then uses that energy to make the air or gas warmer than it would be without the heat pump.

The relationship between the heat pump and the blower is that they are directly connected and work off of each other. When a thermostat sends back a signal, the heat pump is activated and sends hot or cold air based on what is needed. The air is then evenly distributed by the blower.

Another important part of the air handler is the so-called indoor coil, which is relevant to ensuring the smooth operation of the air conditioning and heating modes of the air handler.

The indoor coil contains refrigerant. The refrigerant, then, is positioned right amidst the forced air system and influences the air traveling in this pathway by increasing or decreasing the temperature. The refrigerant is subject to two modes: AC mode and heat mode.

AC Mode - Air Handler Explained

In AC mode, the blower absorbs hot and usually humid air through the ductwork. The refrigerant coil that is placed in the path of traveling air takes in heat emanating from the warm, outside air, and thus effectively leaves it cool. The refrigerant in air conditioning systems circulates around the system to reduce humidity and heat. The refrigerant is a gas, and as it moves, it changes its pressure. This pressure difference causes the gas to cool, and subsequently the air around it as well.

Then, the blower once again takes on its role, now moving the cooled air through the supply ducts and finally blowing it into a room. However, the responsibilities of the indoor coil do not stop there. It also has the responsibility of sending the now-heated refrigerant to a radiator-like coil, which is helpful in disposing of the heat.

Heat Mode - Air Handler Explained

The process of the heat mode is the exact opposite of the AC mode. Air is pulled in by the refrigerant from the cool air outdoors. This heat is then moved into the coil, thus maintaining it at a high temperature.

Then, the blower absorbs cold air, which is moved across the surface of a metal coil. The heated air is then directed to the space being heated. This system works best when the air is circulated constantly.

Furnace Explained: What is it, and What does it do? - Differences Between Furnaces and Air Handlers

You must have already noticed that the air handler has most of its work cut out for it. It is only heavily involved in the movement of air. On the other hand, furnaces are termed “creators of their own heat.”

This is done by burning fuel (usually natural gas or oil) in a combustion chamber or a heat exchanger, within which cool air from the outside is circulated courtesy of the blower fan.

Once the air is sufficiently heated, it travels through the ducts and grates to heat up the rooms. Much like an air handler, the working of a furnace begins with a sign from the thermostat.

When a set temperature is achieved, and the thermostat alerts the system of this condition, the furnace stops burning fuel to produce heat until it is required again.

Meanwhile, once the heated air is blown into your home, any harmful gases that may be produced due to the fuel burning are passed out.

Air Handlers vs Furnaces: The Differences - Differences Between Furnaces and Air Handlers

Knowing how these systems work is a good way to begin differentiating between them.

The biggest marked difference between them, as you probably noticed, is the process of heating. Where the air handler is concerned with moving, circulating, and distributing the heat created by a different source (the heat pump), a furnace is involved in creating its own heat.

A furnace has a conveniently positioned internal combustion box or chamber and thus does not need to borrow from an external source.

The second difference that is also concerned with heat regulation is the presence of the indoor coil. You’ve read that the air handler has an indoor coil.

This presence of this coil makes an air handler more similar to an AC with an added heat extension. On the other hand, most furnaces, unless specifically attached to an air conditioning system, don’t contain an indoor coil.

Air handlers are generally known for their ability to function independently even without using a heat pump, relying solely on the indoor AC coil in climates with harsher summers and flimsier winters.

Furnaces, therefore, don’t have this advantage of running on just the coil and refrigerant. However, they have a leg-up on the handlers in extremely cold weather.

Furnace Vs Air Handler Similarities - Differences Between Furnaces and Air Handlers

Despite the differences, air handlers and furnaces share some significant similarities with each other.

The most well-known similarity is that they both use a blower to distribute the air effectively and move it through the home’s ductwork system.

Additionally, another component common to both units is the thermostat, which kick-starts the heating process for the air handler and the furnace.

Also, both furnaces and air handlers come in a variety of single-speed and variable–speed models. As the speed of the system is the concern of the blowers, it makes sense that both systems share this characteristic.

Which One Is Better? - Differences Between Furnaces and Air Handlers

Clearly, the air handler and the furnace are attributed to their unique features and working model. The question of “Which is better?” falls flat; due to their differences, these air systems cannot be compared purely.

Rather, it is more advantageous for customers to know which heating system suits their living conditions and lifestyle. One of the main factors to consider in that aspect is the climate.

Air handlers are considered more advantageous in lands that are bullied by harsh summers, while furnaces have displayed brilliant resilience in the face of extremely low temperatures.

At the same time, air handlers can also handle mild to moderate winters well, thanks to their heat pump extensions.

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