The evaporator coils in a commercial HVAC system.

HVAC systems (heating, ventilation, and air conditioning systems) are used in homes and businesses to keep the interior environment comfortable and healthy. HVAC systems can be very complex, but some common components underlie the operation of these systems. So, how does a commercial HVAC system work? Let’s take a look.

The Basics of HVAC Systems

HVAC systems are designed to keep people comfortable in all settings by providing a steady supply of fresh air free from impurities such as dust particles or chemicals used in manufacturing processes. The three aspects of any HVAC system are heating, ventilation, and air conditioning.


Modern heating is usually achieved through burning natural gas, then transferred to a heat exchanger which heats the air passing through it. The warm air travels through the air ducts, heating the building or facility. Some older buildings still use boiler systems, which heat water pumped through the building and into radiators, which heat the air.


The ventilation system keeps the indoor air quality healthy and comfortable for employees and customers. Ventilation involves the removal of smoke, dust, carbon dioxide, and otherwise unhealthy or contaminated air, replacing it with filtered outside air.

Air Conditioning

Air conditioning refers to the cooling system. An air conditioner directs air through a refrigerant or water-cooled system. It also removes humidity from the air to not become clammy.

The Main Parts of a Commercial HVAC System

These are the same parts that make up residential HVAC systems, with the only major differences being the size and location of the HVAC equipment.

Four Main Components of an Air Conditioner

Four main components make up any air conditioning system: the compressor, condenser, expansion valve, and evaporator. The compressor is an electrically powered device that compresses the refrigerant from a gas to a hot liquid and moves it through the rest of the air conditioning unit.

      • The condenser removes heat from the hot refrigerant and blows it outside.
      • Next, there is the expansion valve, where the now-cool liquid refrigerant expands into cool gas.
      • Finally, the evaporator is where the refrigerant travels through a coil system. Warm air is drawn in from the building’s interior and blown over the coils, cooling it down and sending it inside.

Four Major Components in a Heating System

You’ll find the following four major components in a typical residential heating system:

    • The heat exchanger is where the heat created by burning natural gas heats the cold air.
    • The blower motor sends the warm air through the ductwork of the building.
    • Every heating system has an air filter that traps dust and other unwanted particles.
    • Ventilation pipes allow excess gas, heat, and vapor created by the furnace to transfer out of the building.

Types of Commercial HVAC Systems

There are three main types of commercial HVAC systems: single split, multi-split, and VRF.

Single-Split System

A single-split system consists of one indoor unit and one outdoor unit and is an ideal choice for smaller commercial buildings, small offices, or restaurants. The furnace and air conditioner will both be tethered to a thermostat.

Multi-Split System

A multi-split system is similar to a single-split system, but in this case, up to nine indoor units can be connected to an outdoor or rooftop unit. This type of system is used in large office buildings and hospitals to heat and cool spaces more efficiently. Multi-split systems are more complex and expensive to design and install.

Variable Refrigerant Flow (VRF) System

A Variable Refrigerant Flow (VRF) system, also known as a variable refrigerant volume (VRV) system, is a commercial HVAC technology that uses a heat pump or heat recovery equipment. VRF systems use only the amount of refrigerant needed and only operate at the required rate due to inverter compressors. In contrast, traditional heating and air conditioning systems are either totally on or off. These units provide a high degree of energy efficiency.

Taking Care of Your HVAC System

Caring for your HVAC system is extremely important – neglecting regular maintenance can cause problems down the road for your employees, customers, and guests, possibly leading to costly shutdowns of your business while the issues are repaired.

Whether it’s maintenance or repairs, when you need any HVAC services you should contact an HVAC contractor you trust. The staff at TEMA Roofing already has decades of experience dealing with commercial spaces, and the same expertise that TEMA puts into your roof will also be put into your HVAC system. The roofing company you trust is now also the HVAC company you trust – contact TEMA’s HVAC services today!