How Do HVAC Systems Work?

Although heating, ventilation, and air conditioning (HVAC) are familiar terms, understanding the systems and how they work together can be a little more complicated. Our goal is to demystify the technologies and discuss which systems are most prevalent in specific climates.

If you’re curious about how HVAC systems work and how they maintain temperature settings and balance humidity, you’ve come to the right place. There are many moving parts that work to warm you up in winter and cool you down in summer. Understanding how to create the perfect temperature solution for your home can be achieved by breaking down the different types of HVAC systems and their parts.

The Fundamentals of HVAC Systems

Your HVAC system’s primary function is to move warm and cold air through your home’s ductwork or through an indoor unit in a ductless system. Your HVAC is more than a single unit — it’s a system made up of multiple units and parts on the inside and outside of your home that works together to meet your temperature, comfort and air quality needs all year long.

Examine the functioning of HVAC systems by examining the primary components that make up a complete system.

Thermostat

Your home temperature is regulated by a programmable thermostat that activates the rest of the HVAC system when it falls above or below your set point. The most important part of your HVAC system is this one, so it’s typically located on walls that are easily accessible. Your thermostat has the ability to be programmed to keep your home at a specific temperature.

Furnace

A furnace is a type of HVAC unit that has a blower and heat exchanger. The location of this is in areas such as the garage, utility closet, attic, basement, or crawlspace of a home. Your home is heated by the furnace using a fossil fuel source like propane or natural gas. The warm air will be distributed through different areas of your home through the duct system ductwork after the furnace heat exchangers generate heat.

Air Conditioner

The unit that sits outside is commonly referred to as an air conditioner. The primary function of an air conditioner is to remove heat from the home. It does this by using refrigerant that circulates between the indoor and outdoor coils to absorb heat from the indoor coil, transfer heat through the line sets and reject heat from the outdoor coil to the outdoor air. 

Heat Pump

Your home can be heated and cooled by a heat pump, which is a third individual HVAC unit. A heat pump uses the same mechanism as an air conditioner to cool your home, then when it’s time to heat, a reversing valve will switch the direction of refrigerant flow to heat the home. When a heat pump is cooling, it’s transporting heat from inside the home to the outside. A heat pump’s heating process involves taking heat from the outside and bringing it inside. Heat pumps, like air conditioners, use an indoor and outdoor coil to transfer heat. 

Air Handler

Air handlers are similar to furnaces, but do not burn fossil fuels. The coil that is typically located on top of the furnace is located in the air handler cabinet. To provide cooling and heating for the home, the air handler works with the outside air conditioner or heat pump. The air handler’s blower is similar to the furnace in that it will circulate cool or warm air through the ducting. In addition to the heat pump operation, air handlers can have supplemental heat strips to provide extra heat.

Air Ducts and Vents

The HVAC units’ hot and cold air are transported and delivered into the rooms throughout your house through air ducts, which are also known as ductwork and vents. It’s crucial to not cover or block them, as they can be found in multiple places in your home.

Different Types of HVAC Systems

Now that you know a little about the different parts of heating and cooling systems, we’ll discuss the main types of HVAC systems and how they work to give you home comfort when you need it most throughout the seasons.

To create a complete system, different individual units are paired together, and these combinations are among the most popular for homeowners. Your local Trane dealer can assist you in determining the right complete system for you based on a variety of factors.

Air Conditioner (AC) and Furnace 

When it comes to HVAC, the combination of an air conditioner and furnace is one of the most common systems. The furnace is responsible for heating your home while the air conditioner is responsible for cooling it. Your thermostat is responsible for sending messages to the furnace and air conditioner to provide heat during the winter and cool during the summer to keep you comfortable.

Furnaces usually generate heat using a fossil fuel source, and then use ductwork to distribute the heat throughout your home based on the thermostat’s setting. The furnace heat exchanger and blower work together to circulate heated air throughout the rooms of your home until the desired temperature is reached.

The air conditioner is responsible for cooling your home on the other hand. The outdoor AC unit has a compressor that pumps refrigerant to an evaporator coil that is located inside near the furnace. The refrigerant takes in heat from your home and transports it through the outdoor coil, releasing it into the outside air to cool your home. 

Heat Pump and Air Handler

A heating and cooling system can be created by combining a heat pump and air handler. A heat pump is capable of cooling your home in the summer and heating it in the winter. The indoor coil in the air handler combines with the outdoor unit to absorb heat in the summer or deliver heat in the winter. The air handler’s blower moves this cool or warm air through the ductwork in the home.

A heat pump is responsible for absorbing heat from the outside and transferring it to the inside for heat. It’s not generating heat so much as transferring it from one place to another.