A rooftop unit can keep working while gradually becoming less reliable.
It may still produce heat or cooling. Tenants may only notice occasional temperature issues. Building staff may be making small adjustments to setpoints or schedules. But weak airflow, unusual noise, frequent cycling, rising energy use, or recurring comfort complaints can all point to a rooftop unit that needs professional attention.
For Edmonton property managers and building owners, early RTU service helps reduce the risk of a more disruptive failure during extreme heat, cold weather, or a busy operating period.
What Is a Commercial Rooftop Unit?
A commercial rooftop unit, often called an RTU, is an HVAC system installed on the roof of a building. Many RTUs provide heating, cooling, and ventilation from one unit.
They are common in commercial properties such as:
- Retail buildings and shopping centres
- Restaurants and food-service spaces
- Offices
- Warehouses
- Industrial facilities
- Schools and institutional buildings
- Multi-unit and mixed-use properties
- Standalone commercial buildings
Because the unit is out of sight, it is easy to assume it is operating properly until there is a noticeable comfort problem or a complete shutdown.
Regular service helps identify issues before the building is relying on the unit during the most demanding weather conditions.
1. Some Areas Are Too Hot or Too Cold
Persistent hot or cold spots are one of the most common signs of RTU trouble.
A single comfort complaint does not always mean the rooftop unit is the problem. However, recurring concerns in the same area, especially when they affect several occupants or continue after thermostat adjustments, should be investigated.
Possible causes may include:
- Weak airflow
- Dirty filters or coils
- Failing fan or blower components
- Damaged belts
- Thermostat or sensor issues
- Problems with dampers or ventilation components
- Refrigerant-related concerns
- Heating or cooling components losing performance
- Control or zoning issues
If one part of the building is consistently uncomfortable, do not assume the only solution is changing the thermostat. The underlying issue may involve equipment, airflow, controls, or distribution.
2. Airflow Is Weak or Inconsistent
Your RTU may be operating, but the building will not receive reliable heating or cooling if airflow is restricted.
Weak airflow can make tenant spaces feel stuffy, too warm, too cold, or slow to respond when temperatures change. It can also place additional strain on the equipment.
Watch for:
- Weak airflow from supply vents
- Rooms that take a long time to heat or cool
- Noticeable differences between nearby areas
- Vents that appear to have stopped supplying air
- Ventilation complaints from occupants
- Airflow that changes significantly throughout the day
Common causes include dirty filters, blocked coils, failing blower motors, worn belts, damaged fans, ductwork concerns, or control issues. A commercial HVAC technician can assess whether the problem is isolated to the rooftop unit or connected to another part of the system.
3. The Unit Runs Constantly or Cycles Too Often
Commercial RTUs are designed to cycle in response to the building’s heating and cooling demand. If the unit turns on and off repeatedly, runs much longer than expected, or appears unable to satisfy the thermostat, it should be inspected.
Frequent cycling can be caused by:
- Thermostat or sensor problems
- Incorrect control settings
- Dirty filters or coils
- Electrical or control-component issues
- Refrigerant concerns
- Failing heating or cooling components
- Airflow restrictions
- A system that is struggling to meet building demand
A unit that runs continuously may also increase energy use and accelerate wear on motors, compressors, fans, and other components.
4. You Hear New or Unusual Noises
Commercial HVAC equipment produces normal operating sound. What matters is a change from the usual sound.
Arrange service if you notice:
- Grinding
- Squealing
- Banging
- Rattling
- Knocking
- Clicking that continues or repeats unusually
- Loud humming
- Excessive vibration
These sounds may be associated with belts, bearings, motors, fans, compressors, electrical components, loose parts, or other mechanical issues.
Do not wait until the noise becomes severe or the unit stops operating. A new sound is often an opportunity to investigate a problem before it results in more extensive damage.
5. Energy Costs Are Increasing
A rise in utility costs does not automatically mean your rooftop unit is failing. Energy use can change with weather, occupancy, operating hours, tenant use, and other building conditions.
However, a noticeable increase without a clear operational explanation may be a reason to assess the HVAC system.
An RTU can use more energy when it is dealing with:
- Dirty filters or coils
- Restricted airflow
- Failing motors or belts
- Refrigerant issues
- Poor control settings
- Excessive cycling
- Equipment that is no longer operating efficiently
- Heating or cooling components under additional strain
A service visit can help identify whether the issue is mechanical, control-related, or connected to building operation.
6. The Unit Is Leaking, Icing Up, or Showing Visible Damage
Rooftop units are exposed to weather, temperature changes, wind, snow, ice, debris, and seasonal wear. A visual inspection can sometimes reveal concerns before they affect the entire building.
Watch for:
- Water around indoor components, drains, or ceilings below the unit
- Condensate drainage issues
- Ice buildup where it should not be present
- Damaged panels or loose components
- Corrosion
- Debris around the unit
- Damaged insulation
- Signs that the unit has shifted, been impacted, or has loose access panels
Any sign of water near electrical components or inside a mechanical space should be addressed promptly. Do not attempt to open or repair rooftop equipment without qualified HVAC personnel and appropriate safety procedures.
7. The Rooftop Unit Has Needed Repeated Repairs
One repair does not necessarily mean a rooftop unit needs to be replaced. Repeated service calls, recurring faults, and multiple component failures, however, are worth tracking.
If your RTU has required frequent repairs, ask your contractor:
- Are these isolated issues or part of a larger pattern?
- Which components are showing the most wear?
- Is the equipment still meeting the building’s needs?
- Are parts readily available?
- What maintenance should be completed now?
- Should the building begin planning for a larger repair, retrofit, or replacement?
A preventative maintenance plan creates the service history needed to make these decisions with more confidence.
Karlen-Kada’s mechanical maintenance programs can include routine inspections, filter replacement, cleaning of fans, coils, and blower components, system-efficiency checks, and customized service schedules based on the building’s equipment and needs.
Keep Rooftop Unit Issues From Becoming Building Problems
A rooftop unit does not need to fail completely before it receives attention. Early service can help building teams address comfort concerns, reduce the risk of unplanned downtime, and make repairs while there is still flexibility in the schedule.
Karlen-Kada provides commercial HVAC maintenance, diagnostics, repairs, mechanical installations, and preventative maintenance programs for Edmonton properties. If your building has recurring comfort issues, weak airflow, unusual RTU operation, or an upcoming seasonal transition, contact Karlen-Kada to schedule an assessment.