How to Optimize Rooftop Units for Summer Cooling

As temperatures rise and energy costs climb, the performance of your rooftop HVAC units becomes more critical than ever. For commercial property managers and residential homeowners with rooftop systems, ensuring these units are operating efficiently isn’t just about staying cool—it’s about controlling energy expenses, avoiding downtime, and extending the life of your investment.
At Sun Mechanical Systems, we’ve helped countless clients across the Chicagoland area prepare their systems for peak performance. Below are the most effective ways to optimize your rooftop units (RTUs) for summer cooling—and how to know when it’s time to call in the pros.

What Is a Rooftop Unit?Rooftop units (RTUs) are self-contained HVAC systems typically installed on the roof of commercial buildings—and occasionally larger residential properties. They deliver heating, cooling, and ventilation all from one unit, making them ideal for space-saving and large-scale comfort control.
But like any mechanical system, RTUs require proactive care to work at peak efficiency—especially during the demanding summer season.

1.Schedule a Pre-Summer HVAC InspectionBefore the hot weather hits full force, it’s essential to have your RTU professionally inspected and tuned up. A thorough inspection will catch issues like:

• Refrigerant leaks
• Blocked filters or coils
• Electrical problems
• Failing blower motors
• Poor airflow

At Sun Mechanical Systems, we perform a comprehensive 19-point inspection to ensure nothing is overlooked. Catching small problems now can prevent major breakdowns later—when you can least afford the downtime.

2. Change Filters FrequentlyDirty air filters are one of the most common causes of inefficiency in rooftop units. When filters are clogged, airflow is restricted, which forces the system to work harder, increasing wear and energy consumption.
Best practice: Check filters monthly during summer and replace them every 1–3 months depending on system usage and environment.

3. Clean Condenser Coils and ComponentsSummer is hard on your condenser coils. When these coils become coated with dirt, pollen, or debris, they can’t effectively release heat, reducing cooling performance.
Regular coil cleaning:

• Improves heat exchange efficiency
• Reduces compressor strain
• Keeps energy bills in check

At the same time, check and clean fan blades, drain pans, and ducts to eliminate buildup and blockages.

4. Monitor Thermostat Settings and ControlsMany RTUs operate with programmable or smart thermostats—but they’re only effective if they’re properly configured. Review all temperature set points, schedules, and occupancy settings to make sure they align with actual building use.
In commercial buildings, make adjustments for:

• After-hours use
• Weekend schedules
• Occupied vs. unoccupied zones

Avoid unnecessary cooling and wasted energy by updating thermostat programming regularly.

5. Check Insulation and Duct SealingLeaky ductwork or inadequate insulation can result in cooled air escaping before it reaches your occupied spaces. That’s money out the window—literally.

• Seal gaps and joints in ductwork
• Insulate exposed rooftop ducts
• Inspect rooftop curbs and penetrations for air leaks

Small leaks can add up to major energy losses over a summer season.

6. Consider Upgrades or RetrofitsIf your rooftop unit is more than 10–15 years old, it may be time to consider an upgrade. Modern RTUs offer significantly improved efficiency, lower noise levels, and compatibility with smart building systems.
Options to explore:

• ECM (Electronically Commutated Motors): Save on fan energy
• Demand-controlled ventilation: Adjusts airflow based on occupancy
• Energy recovery ventilators (ERVs): Capture and reuse cooled air

Sun Mechanical Systems can help assess whether a retrofit or full system replacement makes sense for your building’s needs and budget.

7. Establish a Preventive Maintenance PlanOne of the most effective ways to optimize summer performance—and reduce long-term costs—is to sign up for a preventive maintenance agreement. With routine checks and priority service, you’ll avoid emergency calls and ensure your rooftop units are always running smoothly.
Sun Mechanical Systems offers customized maintenance plans for buildings of all sizes, including schools, offices, warehouses, and more.

Contact Sun Mechanical Systems Today!Summer heat can strain even the most well-designed HVAC systems—but with proper preparation and routine attention, your rooftop units can keep your building comfortable without burning through your budget.
If you're ready to take control of your cooling costs and avoid summer breakdowns, let the experts at Sun Mechanical Systems help.