Building Automation System (BAS) Retrofit
Replace obsolete, pneumatic or orphaned control systems with open BACnet DDC — new front end, graphics, trending and alarms.
Most facilities we walk into have three generations of controls stacked on top of each other: original pneumatics, a 1990s proprietary DDC system nobody can license, and a handful of unit-level controllers that never got integrated. Operators end up running the building from a bypass switch. A BAS retrofit fixes that — and it is the single highest-leverage mechanical investment most buildings can make.
CMI designs and installs open, non-proprietary BACnet systems: new supervisory controllers and network architecture, field controllers at every AHU, plant and terminal unit, replacement sensors and actuators, a modern web front end with graphics that match your actual plant, trending, alarm routing and role-based access. We phase it so the building stays under control the entire time.
Because we are also the mechanical contractor, the retrofit does not stop at the wire. When a retrofit uncovers a stuck damper, a leaking control valve, a fouled coil or a fan that cannot make design airflow, we fix it under the same project instead of documenting it as an exception. That is why our retrofits actually produce the savings and the stable pressure relationships that a controls-only vendor cannot deliver.
Scope & capabilities
- Existing-system audit, point list development and retrofit phasing plans
- Supervisory controllers, field controllers and network infrastructure
- Sensor, transmitter, actuator and control valve replacement
- Trending, analytics, alarm routing, email/SMS notification and reporting
- Remote access, cybersecurity hardening and IT/OT network coordination
- Open BACnet/IP and MS/TP architecture with no proprietary licensing lock-in
- Pneumatic-to-DDC conversion, including terminal units and plant equipment
- Custom graphics, floor plans and plant schematics built from as-builts
- Integration of chillers, boilers, VFDs, power meters, generators and lighting
The technical envelope
- Protocols
- BACnet/IP, BACnet MS/TP, Modbus, OPC, legacy gateways
- Typical size
- 50 – 5,000+ points per building
- Front end
- Web-based, multi-building, role-based access
- Phasing
- Building stays under control throughout the cutover
- Turnover
- Point list, sequences, as-builts, graphics and operator training
Facility types
Building Automation Retrofit — straight answers
- Will we be locked into your controls brand?
- No. We install open BACnet systems and hand over the programming tools, point lists and documentation. If you ever want another contractor to service the system, they can — that is the point of open architecture.
- Can a retrofit happen while the building is occupied?
- Yes. We run the new system in parallel, cut over equipment by equipment — usually plant first, then AHUs, then terminals — and keep temporary control in place so no zone is ever left without heating, cooling or pressure control.
- How much energy will a BAS retrofit actually save?
- In older San Diego buildings with pneumatic or failed controls, 10–25% of HVAC energy is typical, mostly from scheduling, correct minimum airflows, economizer operation, static and temperature reset, and stopping simultaneous heating and cooling. We measure before and after rather than promising a brochure number.
Get a number you can budget against
We walk the plant before we price it. You get equipment condition, options, phasing and a schedule — not a guess with a contingency wrapped around it.