How Long Does It Take to Replace a Commercial Rooftop Unit?

When a commercial Rooftop Unit (RTU) suffers a catastrophic failure—like a cracked heat exchanger or a double-compressor burnout on a 15-year-old system—replacement is the only financially viable option.

However, unlike a residential air conditioner that can be swapped out in a few hours, replacing a commercial RTU is a logistical operation. Facility managers often ask: “How long will my building be without air conditioning?”

Here is the exact timeline and process for replacing a commercial RTU in the Portland and Vancouver metro areas.

Phase 1: The Engineering & Sourcing (1 to 3 Days)

You cannot simply order a generic “10-ton AC unit” off the internet. Commercial RTUs are highly customized.

1. The Site Audit: An HP Mechanical engineer will visit the roof to record the exact dimensions, weight, voltage (e.g., 208V, 460V), and duct configuration (down-flow vs. horizontal) of the existing unit.
2. Sourcing the Unit: If a direct OEM replacement (e.g., swapping an old Trane for a new Trane) is available locally, we can secure the unit immediately. If a custom configuration is required (like adding a factory economizer or VFD), lead times can extend.
3. The Curb Adapter: If you are switching brands (e.g., replacing a Carrier with a Lennox), the hole in the roof will not match the new unit. We must order a custom sheet-metal “curb adapter” to mate the new unit perfectly to the old ductwork without structural modifications to the roof.

Phase 2: Logistics and Permits (1 to 2 Days)

Commercial replacements require careful staging and municipal approval.

1. Rigging and Delivery: We coordinate the delivery and safe lifting of the new unit onto your specific roof structure, whether it’s a single-story restaurant or a strip mall.
2. Permits: If the building is located in dense downtown Portland, we may need to pull specific parking or staging permits to safely execute the swap.

Phase 3: The Execution (1 Day)

Once the logistics are locked in, the actual physical replacement is executed rapidly to minimize your facility’s downtime. The physical swap is almost always completed in a single day.

1. 6:00 AM - Disconnect: Our technicians arrive early to disconnect the high-voltage electrical whips, the gas lines, and the thermostat control wires from the dead unit. The old refrigerant is legally recovered into EPA-approved cylinders.
2. 8:00 AM - The Removal: The dead unit is safely rigged and removed from the roof to be transported for recycling.
3. 9:00 AM - The Drop: The custom curb adapter is laid down and sealed with heavy-duty gasketing to prevent water leaks. The brand-new RTU is then hoisted and set perfectly onto the curb.
4. 10:00 AM to 3:00 PM - Reconnection: Our technicians spend the next several hours reconnecting the gas lines, wiring the high voltage, installing the thermostat controls, and sealing the duct transitions.
5. 4:00 PM - Startup and Commissioning: The system is powered on. We calibrate the gas pressure, measure the airflow, and ensure the economizer is functioning flawlessly.

Minimizing Your Downtime

At HP Mechanical, we understand that every hour your building is without climate control is an hour of lost productivity. By handling all logistics, curb adapter fabrication, and permits in-house, we execute rapid, seamless Commercial HVAC Replacements.

If your RTU is failing, do not wait until it completely dies in the middle of a heatwave. Contact us today for a proactive replacement bid and explore our Commercial Equipment Financing options.