Controls before
capital.
Most of what looks like failing equipment is a sequence, a schedule or a sensor. We examine those first, because a capital project scoped inside a building whose controls are misreporting gets sized against a load profile that is itself an artefact of the fault — and then the new equipment inherits the problem at a larger nameplate.
Three rules,
every building.
They sound obvious written down. They are unusual in practice, because the commercial incentive in this industry points at the replacement rather than at the correction.
Low-cost and no-cost first
Clearing an override, restoring a schedule and fixing a fan-prove chain costs a technician's afternoon. It also removes the load a capital project would otherwise be sized against.
Root cause, not blanket upgrade
A unit whose supply air is 30 °C while it commands full cooling does not have a capacity problem. Replacing it buys a bigger version of the same fault.
Controls expertise plus BAS analytics
Reading a week of trend data against the sequence it was supposed to follow finds things no single site visit will, because the fault is often intermittent or seasonal.
Instrument it,
then argue
about it.
Nothing cut, nothing drilled, and no capital request required to establish what is actually happening. Everything below is non-invasive and reversible.
What we bring on site
- Internal and external thermal imaging, including drone survey where the envelope is in question
- HOBO data loggers on space, supply and return conditions
- Non-invasive ultrasonic flow measurement on hydronic loops
- CT sensors for power and energy at the motor control centre
What we do with it
- Simultaneous analysis across systems rather than one at a time — simultaneous heating and cooling is invisible if you look at either alone
- BAS trend extraction and comparison against the design sequence
- Unit-by-unit fault triage into P0, P1 and P2 by cost and consequence
- Utility baseline regression, so a claimed saving can be separated from a mild winter
A worked
example.
A six-storey mixed-use building in Ontario, about 5,300 m², running at 1.964 GJ/m² against a 1.28 GJ/m² benchmark — roughly 50% above comparable space. Twenty-one air-conditioning units were pulled from the BAS and read against their own sequences. Seventeen zones were outside their comfort band.
| Unit | SAT | Cool cmd | Fan cmd/status | OA damper | What that means |
|---|---|---|---|---|---|
| AC-2 | 25.4 °C | 0% | On / Off | 0% | Command and status disagree: the fan is being asked to run and is not running. No airflow, therefore no cooling, regardless of what the coil is doing. |
| AC-9 | 22.6 °C | 100% | Off / Off | 0% | Cooling commanded at 100% on a unit that is off. A point-mapping or logic fault; the BAS is reporting a state that does not exist. |
| AC-10 | 33.2 °C | 100% | On / On | 100% | Supply air hotter than outside while cooling is at full. Outside-air damper stuck open, heating bleeding through, or both. |
| AC-12 | 30.3 °C | 100% | Off / Off | 100% | The worst case on the building: off, yet reporting full cooling, with the outside-air damper wide open. Mapping, damper and valve faults stacked on one unit. |
| AC-20 | 31.2 °C | 100% | On / On | 100% | Damper stuck, heat bleed, sensor binding. Top priority: it is conditioning outside air at full load and delivering warm supply air to the space. |
Five rows from a twenty-one unit triage. None of these are equipment at the end of its life. All of them were costing energy every hour the building was occupied, and none appear anywhere in a utility bill as anything other than a slightly higher total.
Six patterns,
over and over.
Across the buildings we assess, nearly everything resolves to one of these. Naming the pattern matters because the fix and the cost are completely different depending on which one it is.
- Valve leakage or failed close-off — warm supply air while cooling is active, because the heating coil never fully shuts.
- Outside-air dampers stuck or demand-control ventilation not responding — the building conditions far more outside air than it needs, all year.
- Fan, contactor or VFD status faults — command and status disagree, so the sequence proceeds on the assumption of airflow that is not there.
- Point mapping and sensor errors — the BAS reports a state the equipment is not in, which makes every downstream decision wrong.
- Genuinely undersized cooling or poor heat rejection — the coil is doing its job and the space still does not come down. Kitchens and restaurant zones especially.
- Simultaneous heating and cooling — two systems fighting, paid for twice, invisible unless both are examined together.
P0, P1, P2.
Findings are triaged so an owner can act on the first tier immediately, budget the second, and plan the third. Nothing in P0 needs a capital approval.
Restore the design intent
- Clear all overrides, restore auto on schedules, and document which overrides are allowed going forward
- Fix the fan-prove chain on units showing command/status mismatch
- Valve shutoff test where supply air is warm under cooling; replace passing valves and re-zero supply air sensors
Make the controls tell the truth
- Calibrate CO2 sensors, bind them to the outside-air dampers, set minimum outside air and verify actuator stroke
- Tune sequences so a call cannot stall at partial demand with the fan unproven
- Sensor and actuator replacement where calibration will not hold
Fix what the corrections expose
- Thermostat relocation where sensors sit in ceilings rather than in the occupied zone
- Condenser coil cleaning and heat-rejection verification
- Pump VFDs, permanent metering, DDC VAV integration and plant upgrades — scoped after the controls are honest
Where the
big number
usually is.
On a 23-storey Calgary office tower, the chiller plant was measuring a coefficient of performance of about 1.0 against a 5.0–6.0 benchmark. A COP near 1.0 describes a plant moving water rather than heat.
- Low or no load — a small loop ΔT gives poor cooling efficiency regardless of the machine
- High power input — fouled heat exchangers, compressor or VFD faults, or staging that does not match the load
- Poor water flow — pumps at full speed, imbalanced valves, clogged strainers
- High condenser water temperature — tower or bypass valve faults, dirty fill, low airflow
On that tower the cooling-tower bypass valve was wide open while the tower fans ran at 100%, short-circuiting warm water straight back to the chiller. Closing the bypass above 50% tower operation improves chiller efficiency by roughly 5–10% in tower hours and avoids about 25 kW of needless fan and pump demand during the conflict.
Six or seven
actionable items,
no RFP.
Once the P0 to P2 actions are completed and verified, an estimated 15–35% reduction in utility cost is available without any high-cost replacement, with comfort restored in more than 80% of zones. Pursued as major capital projects the same buildings could reach 30–40% or more — but the staged approach pays back fast, and it builds the evidence the capital case will need anyway.
Sustaining it depends on the unglamorous part: an updated O&M plan, defined acceptance metrics, and enough governance that the overrides do not quietly come back within a year.
Common questions.
It is existing building commissioning — EBCx, sometimes called recommissioning or retro-commissioning. Commissioning proper happens when a building is new and proves it was built to the design. This proves it still runs to the design, ten or thirty years later, after every override anyone ever put in. We are an approved commissioning provider under IESO Save on Energy.
Some of it probably does. The question is what to buy and how big, and that answer changes once the controls are honest. On one mixed-use building twelve condenser compressors had been replaced in eight years against a fifteen-year design life — the replacements were not the problem, they were the symptom of one.
The field work is typically a few days on site plus a logging period, and it is non-invasive: nothing is cut, drilled or taken out of service. Buildings stay occupied and operating throughout. The analysis and reporting run a few weeks behind that, depending on how much trend history the BAS can give us.
Savings are verified under IPMVP against a fitted baseline adjusted to the reporting period's own weather, with the confidence interval published beside the headline number. A mild winter can produce apparent savings that never happened, which is exactly why the baseline is adjusted rather than the result.
Buildings assessed
this way.
14 William Sylvester Drive
1.964 GJ/m² against a 1.28 benchmark, 17 of 21 zones outside comfort, and no capital required in P0 or P1.
444 5th Avenue SW
23 storeys, 1.54 GJ/m², a chiller plant measuring COP ~1.0, and 5,522 GJ of projected annual savings across eight measures.
Ventura Foods
A continuously operating process facility, optimized around production rather than around comfort. Verified savings, no downtime.
Thirty minutes, with the engineer who would run the work.
No cost and no obligation. Bring twelve months of utility bills if you have them — that alone is usually enough to say whether a building has a capital problem or a controls problem.