Here’s a stat that might surprise you: most commercial buildings in Australia are over 20 years old. The HVAC equipment inside them? Often still running fine. Compressors compressing, fans spinning, refrigerant doing its thing. The problem isn’t the hardware — it’s the way it’s managed.
Walk into the plant room of a typical office building built in the early 2000s and you’ll find units controlled by remotes that went missing years ago, schedules that nobody’s updated since the original fit-out, and zero visibility into what’s actually happening across the system. Energy bills arrive, eyebrows go up, and nobody can explain why.
The good news? You don’t need to rip everything out. You don’t need a six-figure capital project. You just need to connect what you’ve already got.
What Does Retrofit Actually Mean?
Let’s be specific, because “retrofit” gets thrown around loosely. In this context, it means adding intelligence on top of existing equipment — not replacing it. Your VRV/VRF units, your hydronic system, your ducted setup — they all stay exactly where they are.
What gets added is a Nexus controller that connects directly to the existing communication bus on your HVAC equipment. Think of it like giving your building a nervous system it never had. The units were always capable of reporting data and receiving commands — they just had nobody to talk to.
What stays: Your existing indoor and outdoor units, your existing ductwork, your existing piping. Nothing gets ripped out.
What gets added: A Nexus controller (sits in or near your plant room), optional zone sensors for temperature and humidity, and a cloud connection to the Nexus iQ™ platform.
What changes: Everything about how you see and manage your HVAC. Real-time visibility into every unit. Remote control from anywhere. Automated scheduling. Fault alerts before things break. Energy reporting that actually makes sense. It’s the same equipment, but now you’re in charge of it.
Is Your Building Ready? Take the Quiz
Not sure if your building is a good candidate? Answer six quick questions and we’ll tell you.
Retrofit Readiness Check
6 quick questions — takes about 30 seconds
The 5 Steps to a Smart Retrofit
Once you’ve decided to go ahead, here’s what the process actually looks like. No surprises, no drawn-out projects.
Step 1: Site Assessment
A Nexus partner visits your site, counts the indoor and outdoor units, identifies the communication bus type (P1/P2, H-Link, M-Net, etc.), and checks network access in the plant room. This usually takes a couple of hours.
Step 2: System Design
Based on the assessment, your partner specifies exactly which Nexus products are needed — the right controller model, any sensor expansions, and the cloud subscription tier. No guesswork, no over-specifying.
Step 3: Installation
The controller gets mounted near your HVAC equipment and connected to the communication bus. Typically takes half a day to a full day. Your units keep running the entire time — no disruption to building operations.
Step 4: Commissioning
Once connected, the Nexus controller automatically discovers every unit on the bus. Zones get named, the cloud connection is established, and your partner configures the initial dashboard layout and alert thresholds.
Step 5: Go Live
You get dashboard access from day one. Schedules are set, alerts configured, and your team can see and control every unit from any device. Most building managers are genuinely surprised at what they discover in the first week.
Want to see this in action?
Book a free demo and see how Nexus iQ can work for your building.
Book a DemoWhat About My Existing BMS?
This is the question we hear most often from larger buildings, and the answer is straightforward: Nexus iQ doesn’t replace your BMS. It works alongside it.
Your BMS is a generalist. It controls lighting schedules, monitors fire panels, manages lifts, and yes, it has some HVAC oversight. But “some” is the key word. Most BMS platforms treat HVAC as a set of binary data points — on/off, setpoint, maybe a fault flag. They don’t give you unit-level diagnostics, refrigerant cycle analysis, compressor health trends, or energy consumption broken down by zone.
That’s what Nexus iQ does. It’s the HVAC specialist sitting next to the BMS generalist. They can share data via BACnet or Modbus if needed — the BMS keeps doing its job, and Nexus iQ adds the deep HVAC intelligence that was never there before. Think of it as a complement, not a competitor.
Real Numbers: What Retrofit Clients Typically See
We could talk theory all day, but numbers speak louder. Here’s what building owners and managers typically report after connecting their existing HVAC to Nexus iQ.
Common Concerns (And Why They Shouldn’t Stop You)
We’ve heard every objection going. Here are the big four — and the honest answers.
“My units are too old”
▼If your units are still running, they can be monitored. The Nexus controller connects to the communication bus — it doesn’t care how old the compressor is. We’ve connected systems that have been running for 15+ years without issue. In fact, older systems often benefit the most from monitoring because they’re the ones most likely to have hidden faults and efficiency losses.
“We don’t have budget for a full upgrade”
▼Good news: a retrofit costs a fraction of equipment replacement. You’re not buying new outdoor units, new piping, or new ductwork. You’re adding a controller and a cloud subscription. Most sites see payback within 12 months through energy savings and avoided emergency repairs alone. This isn’t a capital expenditure — it’s an operational improvement that pays for itself.
“Our tenants will be disrupted”
▼Installation is completely non-invasive. The Nexus controller connects to the communication bus in your plant room — not in the ceiling, not in tenant spaces. Your HVAC units keep running during the entire process. Most tenants won’t even know it happened until they start noticing better comfort and fewer complaints going unanswered.
“We already have a BMS”
▼Perfect — Nexus iQ complements your BMS, it doesn’t compete with it. Your BMS handles the building-wide orchestration. Nexus iQ adds the deep, unit-level HVAC diagnostics, energy analytics, and predictive maintenance that most BMS platforms simply weren’t designed to provide. They work together via BACnet or Modbus integration.
Getting Started
If you’ve read this far, your building is probably a good candidate. The next step is simple: talk to a Nexus partner about your building. They’ll assess your site, tell you exactly what’s needed, and give you a clear picture of costs and timeline — no obligation, no pressure.
Most buildings go from first conversation to live dashboard in under two weeks. The equipment is ready. The technology is proven. The only thing missing is the connection.