The basics of HVAC systems and their components

Over the last decade, HVAC systems have evolved significantly, driven mainly by technological advances and changes in building design and construction. The COVID-19 pandemic further underscored the importance of indoor air quality and ventilation in reducing the spread of airborne pathogens.

In this article, we’ll look at the essential components of HVAC systems, how they’ve evolved, and the most in-demand job roles within the HVAC industry. 

The basics

An HVAC system can effectively control the air conditions of a given parameter through a complex network of components that work together. The main components of an HVAC system include:

Thermostat

The thermostat is the control panel that regulates the temperature in the building. It is usually located on a wall and allows occupants to adjust the temperature according to their preference.

Furnace/heater

The furnace or heater is the most significant component of any commercial HVAC system. It heats the air in the building through a heat pump, solar energy, or natural gas combustion. Recent advancements include the development of high-efficiency furnaces and the increasing use of heat pumps, which can provide heating and cooling.

Air conditioner

The air conditioner is the component that cools the air in the building. It works by absorbing heat from the indoor air and expelling it outside. Modern air conditioners are more energy-efficient and environmentally friendly, using refrigerants with lower global warming potential (GWP).

Ductwork

This network of pipes distributes heated or cooled air throughout the building. It also facilitates the circulation of fresh air and the removal of stale air. Proper duct design and insulation have become critical in minimising energy loss and ensuring efficient airflow.

Vents/registers

These are the outlets (usually on walls, floors or ceilings) through which the heated or cooled air enters the rooms. Adjustable vents and smart registers are becoming popular, allowing for better airflow control and customisation of room-by-room temperature.

Air filters

Air filters remove dust, dirt and other contaminants from the air before it circulates through the building. They are usually located in the ductwork or inside the HVAC unit. Advanced air filtration technologies, including HEPA and electrostatic filters, have been developed to improve indoor air quality.

Humidifier/dehumidifier

These components regulate the humidity levels in the building. A humidifier adds moisture to the air, while a dehumidifier removes excess moisture. Integrated systems, which are becoming more common, automatically adjust humidity levels based on indoor conditions.

How HVAC systems have evolved

The rise of the Internet of Things (IoT) has led to the development of intelligent HVAC systems that can be controlled remotely and adjusted based on occupancy and environmental conditions. These systems can also feed data on energy consumption and system performance to facilities managers, allowing them to optimise their HVAC systems for energy efficiency and occupant comfort.

Innovative HVAC systems have also led to the integration of other building systems, such as lighting, security and fire safety. These integrations allow for greater coordination and control, contributing to energy efficiency, a key consideration in HVAC system design.

With a focus on reducing energy consumption and greenhouse gas emissions, HVAC systems have become more energy-efficient by using variable speed drives, intelligent controls and more efficient heat exchangers. 

In recent years, people have considered using renewable energy sources, and solar and geothermal power have become more common in HVAC system design. These systems can provide heating and cooling using renewable energy sources, reducing energy costs and environmental impact.

In the wake of the COVID-19 pandemic, HVAC systems have evolved to include features such as advanced filtration systems and UV-C lighting to reduce the spread of airborne pathogens and improve indoor air quality. These advanced filtration systems can capture smaller particles, including viruses. HEPA filters, which capture 99.97% of particles down to 0.3 microns, are installed in many HVAC systems, and UV-C lighting can kill viruses and other pathogens.

In-demand job roles in HVAC

The market size of the UK Plumbing, Heating, and Air Conditioning Installation industry has changed over recent years. As of 2024, the industry is expected to grow at a compound annual growth rate (CAGR) of 1.3% until 2026, rebounding from the impacts of the COVID-19 pandemic​.

This recovery is driven by increased demand for energy-efficient HVAC systems and government incentives promoting green technologies.

Between 2018 and 2023, the industry experienced an average modest growth of approximately 0.8% per year. The sector’s expansion is influenced by the need for improved HVAC systems to reduce energy consumption and the rising awareness of environmental sustainability.

In 2024, the industry employs about 165,000 people, including administrative staff, plumbers and HVAC engineers​​. Notably, the market is predominantly served by small and independent firms, with Centrica holding the largest market share at 11.5%​.

Overall, the industry is poised for steady growth, driven by the push for energy efficiency and technological advancements in HVAC systems.

This growth calls for increased skilled workers, leading to more roles in demand. 

These include:

• HVAC Engineers
• HVAC Technicians
• Facilities Managers
• Solar Technicians
• Refrigeration Technicians
• Air Conditioning Technicians

Aside from a degree in mechanical engineering, electrical engineering or a related field, several skills can help you in your HVAC career, including:

• technical knowledge
• troubleshooting skills
• attention to detail
• physical fitness
• communication skills
• time management skills
• safety awareness

Sustainability and future trends

As we look towards the future, sustainability will continue to drive innovation in the HVAC industry. Technologies such as energy recovery ventilators (ERVs), which capture and reuse energy from exhaust air, and advanced heat pump designs are likely to become more prevalent. The industry is also exploring the potential of AI and machine learning to predict maintenance needs and optimise system performance.

Get in touch

If your organisation is hiring building design, construction or facilities management professionals, contact PRS’s expert recruitment team.