By Gary E. Wilson, President & Designated Broker, Wilson Management, Inc.
HVAC is the building system office tenants experience continuously, complain about most, and judge the building by. It is also the largest controllable operating cost in most office buildings, which means the same attention serves the tenant relationship and the budget simultaneously.
This is a working checklist — what to do, when, and which items fail without anyone noticing.
Before the heating season
Before the cooling season
Through the year
The components that fail silently
Three items degrade without producing an alarm, a complaint, or any visible symptom.
Economisers and outside air dampers. Stuck closed, they starve the building of outside air — an indoor air quality problem nobody sees. Stuck open, they admit unconditioned air continuously — an energy cost nobody sees. Neither raises an alert, and both persist indefinitely until somebody physically checks. This is the single strongest argument for scheduled verification over complaint-driven maintenance.
Sensors out of calibration. A thermostat or humidistat reporting a comfortable number while the space sits outside range is a failure that can run for years, because everything looks correct on the panel.
Condensate drains. A blocked drain produces water inside the building — turning the system meant to condition the space into the thing damaging it. Frequently discovered as a ceiling stain.
Indoor air quality
Tenant expectations around ventilation and filtration have risen and are unlikely to fall back. It is now asked about during leasing rather than after a complaint.
The elements that matter:
- Outside air delivery — actually being delivered, not merely designed for
- Filtration level, and whether the equipment can handle it
- Humidity, which in this climate runs high through the wet months
- Localised issues — printer and equipment loads, odours, an unbalanced zone
The filtration trap deserves specific attention. Fitting a higher-rated filter to a system not designed for its pressure drop reduces airflow. That can make comfort and ventilation worse while consuming more fan energy — the opposite of the intent. Whether a system can carry an upgrade is an engineering question with a real answer, and it should be asked before ordering filters rather than after complaints start.
Diagnosing complaints properly
A complaint process that resolves problems looks different from one that manages them.
Record location, time and nature. This is what turns individual grievances into a diagnosable pattern. Three complaints from the same zone at the same time of day is a problem with an answer; three complaints logged as "too cold" is noise.
Investigate before adjusting. The reflex of changing a setpoint in response to a complaint frequently creates the next complaint from the adjacent zone. Two tenants pulling a shared zone in opposite directions is a recurring pattern, and adjusting repeatedly makes it worse.
Distinguish the three causes. A genuine fault, a distribution problem, or an expectation problem. A perimeter office with west-facing glass will be warm on a summer afternoon — that is physics rather than a setpoint, and explaining it honestly is more useful than pretending an adjustment will fix it.
Close the loop. Telling the tenant what was found and what was done resolves a substantial share of dissatisfaction on its own. Tenants tolerate an imperfect building; they do not tolerate feeling ignored.
After-hours service
Most office leases provide conditioning during defined building hours, with service outside those hours available as a billable extra.
Handled as a defined service — stated rate, request process, clear billing — it is a line on a statement. Handled informally it becomes a recurring argument and an unrecovered cost, because tenants working late run systems the landlord pays for and nobody bills.
Knowing when to replace
Equipment reaches a point where continued repair costs more than replacement, and the indicators are cumulative rather than dramatic:
- Service calls to the same unit increasing season over season
- Parts becoming difficult to source
- Refrigerant type being phased down, with cost rising accordingly
- Efficiency well below current equipment
- Inability to hold conditions on the hottest and coldest days
Three service calls to one unit in a season is not three incidents. It is one asset telling you it is finished — and treating it as three separate repairs is how buildings end up replacing equipment in an emergency in August.
Planned replacement can be specified for efficiency, sequenced with other work such as a roof, scheduled in a shoulder season, and competitively priced. Replacement at failure achieves none of those. See Office Energy Compliance and Commercial Asset Planning.
What to record, and why
An HVAC program that produces records is worth substantially more than one that simply gets the work done, because the records are what turn maintenance into planning.
Service history per unit. Which unit, what was done, when, by whom, and what the technician observed. Aggregated over a couple of seasons, this is what identifies the asset approaching the end of its life before it fails.
Complaints with location and time. The pattern is the diagnosis. Without location and time recorded, a complaint log is a list of dissatisfaction rather than an instrument.
Filter changes. Both to confirm the interval is being met and to reveal where loading is heavier than assumed.
Control changes. Every override, who made it, why, and whether it was restored. This single record prevents most of the schedule drift that wastes energy in older buildings.
Readings from independent verification. So that sensor drift is detectable rather than invisible.
None of this is onerous once it is routine. All of it is unavailable retrospectively, which is the argument for starting before you need it rather than when a system is already failing.
Setting the filter interval honestly
Filter intervals are usually inherited rather than decided, and the default carried over from a manufacturer's sheet rarely matches a specific building's exposure.
The variables that actually move it: outside air volume, the surrounding environment, whether construction is running anywhere in the building, seasonal smoke, and the equipment's own tolerance for loading. A building beside a busy arterial road loads filters faster than one on a quiet campus, and a building with tenant fit-out underway loads them faster still.
The practical method is to inspect at the assumed interval for a couple of cycles and set the schedule from what the filters actually look like, then revisit it when conditions change — a construction period, a smoke season, a change in outside air. A filter left in past its useful life restricts airflow, raises fan energy, and pushes the system harder to achieve the same conditions, which is the same cost as the neglect it was meant to prevent.
Where to go next
Our Office HVAC and Air Quality page covers how we manage these systems, and Office Property Management covers the wider service.
Contact us to discuss your building.
About the author
Gary E. Wilson is the President and Designated Broker of Wilson Management, Inc., which he has led in serving property owners across Bellevue and the Greater Seattle area since 1982. With more than 40 years of hands-on experience, Gary helps owners protect and maximize the value of single-family, multi-family, and commercial properties.
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