Here is the next TLDR summary of our education sessions at AHRVegas 2026 This session, “Introduction to Building Automation Systems,” explored the foundational infrastructure of building automation, from pneumatic controls to cloud-native systems. Speakers Scott Cochrane of Cochrane Supply & Engineering and Stephanie Poole of SES Consulting delivered a practical, history-rich overview for building owners, contractors, and engineers.
Session Title: Introduction to Building Automation Systems
Speakers: Scott Cochrane, President, Cochrane Supply & Engineering; Stephanie Poole, Principal, SES Consulting
Focus: BAS infrastructure, open protocols, energy management, and the path to the cloud
What Is a Building Automation System?
A Building Automation System (BAS) goes by many names: Facility Management System (FMS), Energy Management System (EMS), or Building Management System (BMS). A BAS comprises input and output devices connected to controllers. The controllers act as the brains, taking input data and telling outputs what to do. Those controllers are then networked back to a computer or gateway.
Why does this matter for energy? A BAS controls roughly 80 percent of a building’s energy load. Understanding your BAS hardware is critical. It determines which energy-saving strategies you can implement, what data you can collect, and how you plan for future upgrades.
A Brief History of Building Controls
The Pneumatic Era
Pneumatic systems use 100 percent compressed air for control. A compressor creates air pressure that travels through small copper tubes. Inside a pneumatic thermostat, a bimetallic element warps with temperature, changing the air pressure to signal an actuator. You can spot a pneumatic thermostat by listening for a hiss or feeling for air. If you feel no air, it is likely not working.
Pneumatics remain the only truly open protocol because no single company controls air pressure. They are still used in explosive environments like chemical facilities because they generate no sparks.
Direct Digital Control and Proprietary Systems
When computers arrived, manufacturers built their own electronic controllers. Each manufacturer built everything: the computer, controllers, IO devices, and network. This created proprietary systems that would not communicate with other brands.
Open Protocols and Standards
Pressure from building owners led to the adoption of open protocols. BACnet, created by an ASHRAE committee, became the HVAC industry’s open standard. Modbus is common for meters, lighting control panels, and electrical distribution.
Important distinction: Just because a controller says it is BACnet does not mean the system is fully open. You may need a different software tool for each manufacturer, creating a closed proprietary system even though the protocol is open.
BAS Architecture and Components
Controllers: The brains. Each piece of equipment typically gets its own controller. Controllers are powered by 24 volts and live inside electrical panels.
Inputs and Outputs: Inputs include temperature, pressure, and CO2 sensors. Outputs include damper and valve actuators. Running out of available IO points is a common limitation.
Networks: BACnet IP uses Ethernet and offers high bandwidth. BACnet MSTP uses a three-wire shielded cable and offers lower bandwidth. BACnet IP is the gold standard for new projects.
The Front End: The computer or web interface where operators see graphics, trends, and alarms. Web-based graphics offer better trending and easier remote access.
Energy Management Strategies
The two simplest and most powerful strategies are turning things off when not needed and controlling energy based on real demand.
Scheduling: Just putting a building on an occupancy schedule can save 15 to 30 percent of energy.
Demand Control Ventilation: CO2 sensors bring in just enough fresh air. You do not want 100 percent outdoor air in January.
The Persistence Problem: Overrides from comfort complaints or forgotten COVID flush cycles erase savings within months. Efficiency is a continuous process, not a one-time setup.
Systems Integration and Master Systems Integrators
You do not always need to rip and replace old controllers. Software drivers can translate proprietary languages to BACnet or Modbus, allowing you to reuse existing equipment.
A Master Systems Integrator (MSI) uses products like Tridium Niagara to create a common software layer that integrates with HVAC, lighting, meters, and security systems. This approach can save significant money. One client received a $350,000 quote to replace all controllers. An MSI accomplished the same integration for a quarter of that cost.
Not every system should be integrated. Life safety systems are typically standalone due to code requirements.
The Cloud and AI
The move to cloud-connected systems is driven primarily by cybersecurity. A cloud-based system allows remote access without exposing the building’s network directly to the internet. The cloud also provides virtually infinite computing power for artificial intelligence and machine learning applications that cannot run on small controllers.
Best Practices for Today
Open Protocol: BACnet IP is recommended.
Web-based graphics: Easier to use and offer better trending.
Strong Trending Capability: Aim for a full year of data.
Cloud Ready or Cloud Native: Ensures cybersecurity and positions you for future AI tools.
Plan for Persistence: Build a plan for continuous monitoring and recommissioning.
Speaker Profiles
Scott Cochrane is President of Cochrane Supply & Engineering, a BAS distributor representing Honeywell, Johnson Controls, and Distech. He is second-generation in the industry and serves on the AutomatedBuildings.com Editorial Board.
Stephanie Poole is a Principal with SES Consulting, an energy consulting firm specializing in mechanical controls design and energy management. She helps clients understand the best upgrade pathways for their buildings.
All AHR Expo 2025 education sessions are available on the Cochrane Supply YouTube channel and at AutomatedBuildings.com.
