If you're managing a building or have recently taken over an older property, chances are you're keeping a close eye on your HVAC system. Maybe you're noticing rising energy bills, inconsistent temperatures, or louder-than-usual noises from the unit. Or maybe you're simply wondering how much life is left in the system. This guide will walk you through the average lifespan of commercial HVAC systems, how to spot trouble early, and when it's time to repair or replace.

Average lifespan of a commercial HVAC system

Most commercial HVAC systems last between 15 and 20 years if properly maintained. Like any mechanical equipment, performance will start to decline as the system ages. Here are some general lifespan estimates by component:

Usage patterns, climate, maintenance history, and installation quality all play a role in determining the actual service life.

How long does ductwork last?

Ductwork is often overlooked, but it has a lifespan of its own. On average, duct systems last between 20 and 25 years. However, they can start to degrade earlier if:

• They're exposed to moisture or mold
• There are leaks or poor connections
• Insulation has deteriorated
• They weren’t properly designed for the space

Older ductwork may cause energy loss of up to 30 percent due to leaks or inefficiencies, which means even if your HVAC unit is functioning, the system overall might not be performing at its best.

The good news is that ductwork doesn't always have to be replaced all at once. In large buildings or occupied spaces, it can often be done in stages. Many building managers start with the most damaged or high-priority sections—like areas with poor airflow, mold, or visible deterioration. Replacing ductwork in phases, especially during tenant improvements or scheduled downtime, helps spread out costs and minimize disruptions.

Signs your commercial HVAC system is wearing out

Here are some signs your system may be nearing the end of its life:

• Hot and cold spots throughout the building
• Unusual noises or odors
• Short cycling (frequent starts and stops)
• Poor airflow
• Increased humidity indoors
• Rising energy bills
• Frequent service calls or part replacements
• Declining indoor air quality due to poor filtration or dust buildup

Temperature swings, excess humidity, or stale air can lead to employee discomfort, tenant complaints, or even lost business. A poorly performing HVAC system isn’t just inefficient—it’s disruptive.

Repair vs. replace: how to decide

Sometimes, a repair is all that’s needed. Other times, you’re better off investing in a replacement. Here’s what to consider:

• Age: If your HVAC is over 15 years old and facing major issues, replacement may be more cost-effective.
• Cost of repairs: A common rule of thumb is if the repair cost exceeds 50 percent of the replacement cost, it's time to upgrade.
• Efficiency: Older systems usually have lower SEER (Seasonal Energy Efficiency Ratio) ratings. New systems are significantly more energy efficient.
• Occupant comfort: Inconsistent temperatures or poor air quality impact tenant satisfaction and productivity.
• Building usage: A system that was right for a previous tenant might not meet current demand.
• Service history: A system that’s been maintained well might be worth one more repair. But a history of breakdowns points toward replacement.

Older HVAC systems often struggle to maintain good indoor air quality, especially if ducts haven’t been cleaned or the system lacks proper filtration. Dust, allergens, and poor ventilation can build up over time.

How to extend the life of your HVAC system

If your system is still in decent shape, you can keep it running efficiently for years with proactive care:

• Schedule routine maintenance (quarterly or at the start of each heating/cooling season)
• Replace air filters regularly
• Clean condenser and evaporator coils
• Calibrate thermostats and building automation systems
• Inspect ductwork for leaks or insulation gaps
• Keep mechanical rooms clean and accessible

Working with a qualified HVAC partner can help you catch small problems before they become big expenses.

When to upgrade your commercial HVAC system

There comes a point when upgrading makes more sense than another repair. You might want to consider a full replacement when:

• The unit is more than 15–20 years old
• Energy bills keep rising despite repairs
• You’re planning renovations or repurposing the space
• You’re pursuing LEED or Energy Star certifications
• You want to qualify for utility rebates or tax incentives

Modern HVAC systems offer features like variable speed motors, smart controls, and better zoning capabilities—all of which can save money and improve comfort.

If your building has been renovated, expanded, or reconfigured for a new tenant, your HVAC system might no longer match the updated floor plan or heating/cooling load. Undersized systems lead to inconsistent comfort and higher wear.

Final takeaway

Your commercial HVAC system is one of the biggest investments tied to your building’s performance and occupant satisfaction. Knowing how long it should last, when to schedule maintenance, and when to consider an upgrade will help you avoid downtime and make smarter capital planning decisions.

If you're ready to evaluate your HVAC system, contact one of our experts, and we can help you weigh your repair and replacement options with confidence.