Why Is My Commercial Air Conditioner Short Cycling?
A guide for business owners, property managers, and facility supervisors across Ontario.
If your commercial air conditioning system is frequently turning on and off before reaching the desired temperature, you’re likely experiencing a common HVAC issue known as short cycling. While it may seem like a minor nuisance, short cycling can significantly impact system performance, energy efficiency, and indoor comfort—especially in commercial environments where reliability and uptime are essential.
In this article, we’ll explain what short cycling is, the most common causes in commercial HVAC systems, the potential impact on your business operations, and what steps you can take to fix and prevent it.
What Is Short Cycling in a Commercial HVAC System?
Short cycling refers to an air conditioning system starting up and shutting down in rapid succession without completing a full cooling cycle. In commercial HVAC applications—whether in retail spaces, warehouses, or office buildings—this abnormal cycling pattern leads to:
- Inconsistent temperature control
- Higher operating costs
- Excessive strain on mechanical components
- Increased risk of system failure
Key Causes of Short Cycling in Commercial AC Units
1. Improperly Sized HVAC Equipment
One of the most common and overlooked causes of short cycling is incorrect HVAC sizing.
- Oversized units cool the space too quickly and shut off before humidity is properly removed or temperatures stabilize.
- Undersized systems run inefficiently, struggling to meet demand, often leading to rapid on-off cycles.
2. Thermostat Issues and Poor Placement
In commercial facilities, multiple zones and large open areas rely on precise thermostat readings for accurate control. If a thermostat is:
- Calibrated incorrectly
- Installed near heat sources, vents, or direct sunlight
- Located in an unrepresentative part of the building
3. Clogged or Dirty Air Filters
Restricted airflow due to dirty or clogged filters forces the HVAC system to work harder, potentially causing it to overheat and shut down prematurely. In commercial environments, where air quality and system runtime demands are higher, filters should be checked and replaced more frequently than in residential settings.
Recommended filter check schedule for commercial HVAC systems: every 30–60 days, depending on usage and indoor air conditions.
4. Low Refrigerant Levels or Leaks
Low refrigerant levels—often caused by leaks in the system—can lead to pressure imbalances, poor cooling performance, and overheating. In turn, this causes the AC unit to shut off before completing its cycle.
This is particularly concerning in commercial settings where uninterrupted climate control is critical (e.g., server rooms, manufacturing floors, retail environments).
5. Frozen or Dirty Evaporator Coils
Evaporator coils are responsible for absorbing heat from the air. If they become dirty or freeze over due to restricted airflow or refrigerant issues, the system may shut down to prevent further damage. This contributes to repeated short cycling and inefficient operation.
Routine coil cleaning and professional inspections are essential components of any commercial HVAC maintenance plan.
6. Faulty Low-Pressure Switch or Electrical Controls
Certain electrical components—like the low-pressure switch—are designed to protect your HVAC system from operating under unsafe conditions. If these parts are malfunctioning, they can prematurely shut down the system or prevent it from completing its cycle.
In commercial systems, such faults require diagnostics by licensed HVAC professionals familiar with high-capacity equipment.
7. Leaky or Blocked Ductwork
Poorly maintained or aging ductwork can lead to:
- Air pressure imbalances
- Uneven airflow across zones
- Energy waste
- Temperature fluctuations
Why Short Cycling Is a Serious Issue for Commercial Buildings
Short cycling is more than just a mechanical inconvenience. For businesses, the consequences can be costly and far-reaching:
1. Increased Energy Consumption
Commercial HVAC systems draw significant power during each start-up cycle. Frequent cycling wastes energy and drives up utility bills, especially during peak summer months.
2. Reduced Equipment Lifespan
Repeated cycling puts added stress on high-cost components like compressors, motors, and capacitors. This accelerates wear and increases the likelihood of unplanned downtime or early system replacement.
3. Inconsistent Comfort and Indoor Air Quality
Short cycles result in poor humidity control and uneven temperature distribution across zones, leading to discomfort for employees, customers, or tenants.
4. Risk of Operational Downtime
For facilities that depend on stable environmental conditions—such as medical offices, data centres, or food storage facilities—short cycling may directly impact operations, safety compliance, or inventory integrity.
How to Fix and Prevent Short Cycling in Commercial HVAC Systems
1. Schedule Preventative Maintenance
Regular maintenance is the most effective way to identify and resolve early signs of short cycling. This includes:
- Cleaning or replacing air filters
- Checking refrigerant levels
- Inspecting thermostat placement and calibration
- Reviewing ductwork and airflow
- Testing electrical components
A planned maintenance agreement with a trusted HVAC partner ensures that potential issues are addressed before they impact business continuity.
2. Reassess HVAC System Sizing
If your building has undergone renovations, occupancy changes, or layout adjustments since the HVAC system was installed, it may no longer be properly sized.
Our team at LG Mechanical performs detailed commercial HVAC load calculations to determine the optimal unit size and configuration for your space.
3. Upgrade to Smart Thermostats or Zoning Controls
Modern commercial HVAC systems can be paired with smart controls and zoned thermostats to improve temperature accuracy and reduce short cycling.
These technologies provide:
- Real-time performance monitoring
- Precision control across zones
- Reduced strain on components
- Better energy management
4. Address Mechanical or Electrical Failures Promptly
Short cycling due to failing components like compressors, control boards, or sensors should be diagnosed and addressed quickly to prevent cascading failures.
LG Mechanical offers rapid-response service calls across Ontario to support businesses with urgent HVAC needs.
Final Thoughts: Protect Your Building and Bottom Line
Short cycling is a warning sign that your commercial HVAC system is not operating as it should. Left unresolved, it can lead to equipment damage, operational inefficiencies, and avoidable expenses.
Whether you operate a multi-tenant office, healthcare facility, retail complex, or industrial site—reliable temperature control is non-negotiable.
Book a Commercial HVAC Assessment with LG Mechanical
At LG Mechanical, we specialize in commercial HVAC solutions across Ontario. Our experienced technicians are trained to handle complex systems and proactively resolve issues like short cycling before they affect your business.
📞 Call 1-800-123-4567
💼 Visit lgmechanical.ca to schedule an inspection or maintenance appointment.
LG Mechanical – The Commercial HVAC Partner You Can Count On.
