Many commercial HVAC systems in Arlington and Fort Worth perform normally for most of the year but fall behind during the hottest part of summer.

That doesn’t always mean something is broken. In many cases, the system is operating as designed but can’t keep up with peak demand.

When temperatures rise and heat load builds throughout the day, underlying limitations in capacity, airflow or system design become more noticeable.

Peak Summer Conditions Push HVAC Systems to Their Limits

Commercial HVAC systems are typically designed around expected conditions, not the most extreme temperatures of the year. During heat waves or prolonged high temperatures, systems may be pushed close to their maximum output.

The highest demand usually occurs in the late afternoon. Outdoor temperatures are at their peak, and heat has been building in the roof, walls and interior spaces throughout the day. At that point, the system is working against both ongoing heat gain and accumulated heat within the building.

Even a properly functioning system can struggle to maintain setpoint under these conditions.

When Cooling Load Exceeds System Capacity

Cooling load is influenced by both internal and external factors:

• Internal load from occupants, equipment and lighting
• Solar heat gain through windows, walls and roofing
• Insulation levels and overall building envelope performance

These conditions are rarely static for the life of a commercial structure. Tenant buildouts, added equipment or higher occupancy can increase demand beyond the original design. A system that was properly sized years ago may no longer match the building’s current usage.

When that happens, the system may run continuously during peak hours without reaching the desired temperature.

Zoning Limitations and Air Distribution Issues

Temperature issues are not always tied to total system capacity. In many buildings, the problem is how cooling is distributed.

Even when the system has enough total capacity, uneven airflow or limited zoning can prevent certain areas from receiving enough cooling during peak demand.

Common contributors include:

• Duct layouts that no longer match how the space is used
• Long or restrictive duct runs that reduce airflow
• Thermostat locations that don’t reflect actual conditions in the space

Aging Equipment Loses Capacity Over Time

Aging HVAC equipment may experience reduced cooling capacity, weaker airflow and less efficient heat transfer. The system may still operate and keep the building comfortable under moderate conditions, but struggle during peak demand.

In many cases, this decline happens slowly enough that it isn’t noticeable until the hottest days of the year.

Why Problems Show Up in the Afternoon First

During summer in DFW, the west-facing walls and windows are subjected to relentless sun exposure for four or five hours during the workday, when buildings are also generating heat from occupants, lighting and equipment.

By late afternoon, the system is trying to offset both solar heat gain and accumulated internal heat load. If capacity is limited or airflow is uneven, the building may fall behind at that point even if it feels comfortable earlier in the day.

When It’s a System Limitation vs a Correctable Issue

Not every performance issue requires full system replacement. Some problems can be addressed with targeted improvements, while others point to broader limitations.

Issues that may be correctable include:

• Airflow restrictions or duct issues
• Control or thermostat problems
• Minor capacity shortfalls in specific areas

More significant limitations may include:

• Equipment that is undersized for current building use
• Multiple units showing signs of age or declining performance
• System design that no longer aligns with how the building is used

Understanding the difference is important before making decisions about repair or replacement.

What to Evaluate Before Replacing Equipment

Tom’s Commercial can evaluate your existing equipment and air distribution in the context of your building’s unique design and envelope performance to determine what, if anything, should be done. A typical evaluation may include:

• Comparing current cooling load to system capacity
• Reviewing ductwork and airflow performance
• Assessing zoning and control strategies
• Evaluating the condition of existing equipment

Before investing in expensive HVAC retrofitting or replacement projects, it’s useful to understand whether unseasonable temperatures, changing occupancy, higher heat generating tenants or other new factors could be contributing to current cooling challenges.

Get a Clear Assessment of Your Building’s Cooling Performance

Tom’s Commercial works with building owners and facility managers throughout Arlington and Fort Worth to assess HVAC performance and identify practical solutions based on how each building is used. Call (817) 857-7400 to schedule an evaluation or request a proposal.