What Are the Most Common Types of Commercial HVAC Systems?
Boulder, July 29, 2024- Commercial buildings have unique heating, ventilation, and air conditioning (HVAC) needs due to their size, diverse spaces, and varying uses. Choosing the right HVAC system is essential since it can significantly impact occupant comfort, energy efficiency, and operational costs.
This article covers five of the most commonly used commercial HVAC systems, explaining how they work, their advantages and disadvantages, and where they’re typically used.
If you’re considering implementing a new HVAC system for your commercial building (or need service or repairs for an existing system), you’ll want to talk with experts like our team at Timberline Mechanical. However, the information below provides a solid foundation for that conversation.
HVAC Systems to Consider for Your Commercial Building
The list of system types used for commercial buildings is long, particularly if you include the many ways to combine different components into one comprehensive system. However, five systems that merit consideration for most commercial buildings are:
1. Single-Split Systems
Single-split systems are the simplest form of commercial HVAC. They consist of one outdoor unit (condenser) and one indoor unit (air handler). The outdoor unit contains the compressor and condenser coil, while the indoor unit has the evaporator coil and blower fan. Refrigerant circulates between these units, enabling heat exchange and temperature control.
How they work
In a single-split system, the compressor pressurizes refrigerant, causing it to heat up. This hot refrigerant travels to the condenser coil, where it releases heat to the outside air and cools down. The now-cooled refrigerant flows to the evaporator coil, absorbing heat from the indoor air and cooling it. The blower fan then circulates this cooled air throughout the space.
Advantages
- Cost-effective to install and maintain. Single-split systems are often the most budget-friendly option for small commercial spaces.
- Adequate capacity for smaller commercial spaces. They are well-suited for spaces up to approximately 1,500 square feet.
- Easy to operate and control. These systems typically come with straightforward thermostats.
- Zoning for independent temperature control. With the addition of zoning kits, even single-split systems can offer some temperature customization.
Disadvantages
- Limited capacity for larger buildings. They may not be able to adequately cool or heat larger spaces.
- Lower energy-efficiency. Their efficiency is lower compared to more advanced options like VRF.
- Noise. Outdoor units, especially older models, can produce significant noise.
Ideal applications
Single-split systems work well in small offices, retail stores, restaurants, and individual hotel rooms.
2. Multi-Split Systems
Multi-split systems are extensions of the single-split concept. They have one outdoor unit connected to multiple indoor units. Each indoor unit can be independently controlled, allowing for customized temperature settings by zone.
How they work
Multi-split systems operate similarly to single-split systems, but with multiple indoor units pulling refrigerant from the same outdoor unit.
Advantages
- Greater zoning flexibility. This is ideal for buildings where various areas have distinct temperature needs.
- More energy-efficient than multiple single-split systems. One outdoor unit serving multiple zones is generally more efficient than individual systems.
- Quieter operation. The outdoor unit typically runs at a lower speed, reducing noise.
- Suitable for medium-sized commercial buildings. Multi-split systems can effectively cool or heat spaces of around 5,000 square feet.
Disadvantages
- Higher upfront cost than single-split systems. The added complexity and multiple indoor units increase the initial investment.
- Limited capacity for very large buildings. Multi-split systems typically aren’t suitable for larger spaces.
Ideal applications
Multi-split systems work well for multi-tenant buildings, hotels, schools, and small office complexes.
3. Variable Refrigerant Flow (VRF) Systems
VRF systems are highly efficient and adaptable HVAC solutions. They have a single outdoor unit connected to multiple indoor units. The key difference lies in their ability to vary the flow of refrigerant to each indoor unit based on demand in real time. This precise control optimizes uses less energy while optimizing comfort levels.
How they work
An inverter-driven compressor in the outdoor unit adjusts refrigerant flow to match the cooling or heating needs of each indoor unit. This ensures consistent temperature control and reduces energy consumption.
Advantages
- Excellent energy efficiency. VRF systems are known for their exceptional efficiency.
- Zoned temperature control. Each indoor unit can be set to a different temperature, providing personalized comfort.
- Quiet operation. Both indoor and outdoor units are designed to minimize noise.
- Simultaneous heating and cooling capabilities. VRF systems can provide heat to one zone while cooling another simultaneously.
- Suitable for various commercial building sizes. They can be scaled up or down to serve large or small structures.
Disadvantages
- Higher upfront cost than other systems. The advanced technology and complexity of VRF systems make them more expensive initially.
- Requires specialized installation and maintenance. Proper installation and ongoing maintenance are crucial for optimal performance.
Ideal applications
VRF systems can be an excellent choice for large office buildings, hospitals, data centers, hotels, and multi-use complexes.
4. Variable Air Volume (VAV) Systems
VAV systems are commonly used in large commercial buildings. They consist of a central air handling unit (AHU) that supplies conditioned air to multiple zones. Each zone has a VAV box that modulates airflow based on temperature requirements, ensuring consistent comfort and energy savings.
How they work
The AHU achieves the desired air temperature and humidity level. The air is then distributed through ductwork to VAV boxes in each zone. VAV boxes contain a damper that opens or closes to adjust airflow based on the zone’s thermostat setting.
Advantages
- Excellent energy efficiency due to variable airflow. VAV systems avoid wasting energy by only delivering the necessary amount of air to each zone.
- Zoned temperature control. Each zone can maintain its desired temperature independently.
- Accommodates varying occupancy levels. The system adjusts airflow based on the number of people in a space, optimizing comfort and efficiency.
Disadvantages
- Complex system with higher upfront costs. The centralized AHU, ductwork, and VAV boxes can be costly to install.
- Requires careful design and balancing. Proper design and implementation is crucial to achieve optimal performance and save energy.
- May not be ideal for spaces with high ventilation needs. VAV systems may not be the best choice for areas that require frequent air changes for air quality.
Ideal applications
VAV systems are often the right system for large office buildings, shopping malls, hospitals, and schools.
5. Rooftop Units (RTUs)
RTUs are packaged HVAC systems installed on a building’s roof. They typically have a compressor, condenser, evaporator, and blower fan in a single unit. RTUs are often the preferred choice for people looking for ease of installation and maintenance.
How they work
These systems work the same way as single-split systems, but with all components housed in a single unit on the roof.
Advantages
- Easy installation and maintenance. RTUs are self-contained, making installation and servicing relatively straightforward.
- Saves indoor space. The rooftop location frees up valuable space inside the building.
- Can be zoned for independent control. Some RTUs can be configured to provide separate temperature control for different zones.
- Suitable for a wide range of commercial building sizes. RTUs come in various sizes to meet the needs of all types of buildings.
Disadvantages
- Exposed to weather elements. Harsh rooftop environments can affect the lifespan of the RTU.
- Noise. The sound from an RTU can be an issue if the unit is close to occupied spaces.
- Less energy-efficient than some systems. RTUs may not be as efficient as VRF or VAV systems.
Ideal applications
RTUs are common at retail stores, restaurants, warehouses, schools, and standalone offices.
Get Attentive Service for Your Ideal HVAC System
Just as important as choosing the right HVAC system for your commercial building is taking steps to keep it running at peak efficiency after implementation.
Contact Timberline Mechanical today to learn about our range of services, including commercial HVAC preventative maintenance, repairs, and special projects.
