Rooftop Unit Repair & Service in San Diego, CA
Rooftop HVAC units keep commercial buildings comfortable without occupying ground-level mechanical space, but when one fails on a 90-degree San Diego afternoon, the entire building feels it fast. Redwood Heating & Air San Diego handles rooftop unit diagnosis, repair, and replacement through our Emergency & Commercial HVAC services for commercial property managers and business owners across the city – the kind of work that needs to be diagnosed right the first time, not after a second or third return visit. Call us at (844) 875-9451 and Gregory Hahn will make sure your system gets the attention it deserves.
As part of our Emergency & Commercial HVAC in San Diego service, rooftop unit work is something we’ve handled for 13 years across a wide range of equipment brands and building types. Whether it’s a mid-size office suite in Mission Valley, a retail strip in Kearny Mesa, or a warehouse near the Port, we’ve seen the full range of what San Diego’s climate does to rooftop equipment – and we know how to fix it.
What a Rooftop Unit Does and Why It Matters
A rooftop unit – often called an RTU – is a self-contained HVAC system mounted on the roof of a commercial building. It handles heating, cooling, and sometimes ventilation from a single cabinet, sending conditioned air down through the building’s ductwork. Because everything is in one place, RTUs are efficient to install and easy to access for maintenance. But that rooftop exposure is also their vulnerability: UV radiation, marine air off the Pacific, and the dust that blows in from the inland valleys all accelerate wear on components that a typical split system never has to deal with.
In San Diego specifically, the salt-laden coastal air common from Ocean Beach to Point Loma accelerates corrosion on condenser coils and electrical contacts faster than in inland climates. Buildings along the I-15 corridor deal with summer heat spikes that push RTUs harder than their rated duty cycles were designed for. Gregory Hahn founded Redwood Heating & Air with 13 years of hands-on fieldwork behind him, and that local environmental knowledge shapes how we diagnose every unit we service.
Signs Your Rooftop Unit Needs Service in San Diego
- Uneven temperatures across the building. If one zone is cold and another is stuffy, the RTU’s dampers, controls, or ductwork connections are the usual suspects – especially in buildings where the unit hasn’t been serviced in a year or more.
- Higher-than-normal utility bills. An RTU that’s running longer cycles than it used to in order to hit setpoint is working around a problem. Dirty coils, low refrigerant charge, or a failing compressor all show up first in the energy bill before they show up as a full breakdown.
- Unusual noise from the rooftop cabinet. Rattling panels, grinding bearings in the blower or condenser fan motor, and banging on startup are mechanical warnings. Ignoring them typically turns a $300 repair into a $1,500 one.
- The unit short-cycles or locks out on a fault code. Modern RTUs from Trane, Lennox, and Rheem log fault codes that tell a trained technician exactly what the controls detected. Reading those codes correctly requires brand-specific knowledge – not just a general scan.
- Visible water intrusion or rust near the unit’s base. San Diego doesn’t get heavy rain, but marine fog and condensation can pool around poorly sealed RTU curbs. Water sitting near electrical controls is a serious problem that needs attention before it causes a shutdown.
- The system simply won’t turn on. A complete failure during summer – common in San Diego’s June-through-September heat window – usually means a failed contactor, blown fuse, compressor issue, or failed control board. These are time-sensitive repairs in a commercial setting where employees and customers are waiting.
Our Rooftop Unit Service Process
We don’t show up to a rooftop unit call with a clipboard and a guess. Every visit follows a structured diagnostic sequence that Gregory Hahn developed over 13 years of commercial service calls across San Diego County.
- Intake and fault history review. Before we climb to the roof, we talk to the building manager or on-site contact. We want to know when the problem started, whether the unit has a service history, and what the building’s occupancy schedule looks like. That context changes what we prioritize on the diagnostic.
- Rooftop inspection and safety check. RTU work is rooftop work, which means fall hazards, live electrical panels, and high-pressure refrigerant lines are all in play. Our technicians work with proper fall protection and follow OSHA rooftop safety protocols. We check the unit’s mounting curb, weatherproofing seals, and the condition of the cabinet before we open anything.
- Full electrical and mechanical diagnostic. We measure supply and return air temperatures, check refrigerant pressures and superheat/subcooling values, test contactor voltage, inspect the heat exchanger if it’s a gas-heat unit, and read any fault codes stored in the controls. For units from Trane or Lennox, we can access proprietary diagnostic data that a non-certified technician wouldn’t know to look for.
- Honest repair recommendation with upfront pricing. After the diagnostic, we walk you through what we found in plain language – what’s failing, what caused it, and what it’ll cost to fix. If there are multiple options (repair versus component replacement versus full unit replacement), we lay out all of them with honest guidance on which makes financial sense for the equipment’s age and condition.
- Repair or replacement execution. We carry a broad inventory of common RTU parts on the truck: contactors, capacitors, fan motors, filters, fuses, and control boards that fit Goodman and Rheem units, which are common across mid-size San Diego commercial properties. For specialty parts or older units, we source quickly from our supplier network to minimize downtime.
- Post-service verification and documentation. After the repair, we run the unit through a full operational test – confirming airflow, temperature split, refrigerant charge, and control sequencing – before we sign off. We document the work so building managers have a service record for future reference or warranty claims.
Rooftop Unit Repair and Replacement Pricing in San Diego
Rooftop unit service in San Diego runs a wide range depending on what’s failed, the size of the unit, and whether you need a repair or a full replacement. Here’s a realistic breakdown of what we see in our service calls across the city:
| Service Type | Typical Price Range |
|---|---|
| Diagnostic / Service Call | $95 – $175 |
| Contactor or capacitor replacement | $180 – $350 |
| Condenser or blower fan motor replacement | $350 – $650 |
| Refrigerant recharge (per pound, R-410A) | $75 – $125 / lb |
| Control board replacement | $400 – $900 |
| Coil cleaning (evaporator or condenser) | $250 – $500 |
| Compressor replacement | $1,200 – $2,800 |
| Full RTU replacement (3-5 ton commercial) | $5,500 – $14,000+ |
These ranges reflect San Diego market rates as of 2025-2026. Actual cost depends on the unit’s tonnage, brand, age, and accessibility on the roof. A Trane or Lennox unit with available stock parts will typically cost less to repair than an older unit requiring custom-sourced components. Units in coastal zip codes like 92101, 92106, or 92118 often show accelerated corrosion that adds time to coil cleaning or electrical work.
We don’t quote over the phone without seeing the unit – that would be guessing, not pricing. But estimates are free after the diagnostic, and we’ll give you a written breakdown before any work begins. Call (844) 875-9451 to schedule.
Why San Diego Property Managers Call Redwood Heating & Air
Most commercial HVAC companies in San Diego either specialize in one or two brands or send out rotating field crews with limited diagnostic depth. Gregory Hahn built Redwood Heating & Air around a different model: the founder does the technical work, holds the Master Technician designation, and is accountable for every diagnosis that goes out under the company name. After 13 years and 428+ verified reviews averaging 4.6 stars, that approach has earned a track record that most local HVAC operations can’t match.
For rooftop units specifically, multi-brand fluency matters more than almost any other service category. A building might have a Goodman RTU that was installed in 2014, replaced with a Rheem unit in 2019, and be considering a Trane for the next replacement cycle. We’ve worked on all of them. We know how their control sequences differ, where they fail under San Diego’s climate conditions, and which repairs are worth making versus which units are past the point of return.
We also understand what it means for a business to be without HVAC. A retail store in Mission Hills losing cooling on a Saturday afternoon has maybe a four-hour window before it affects sales and customer comfort. A tech office in Sorrento Valley can’t put employees in a building that hits 85 degrees. We treat commercial calls with that urgency, and our 24/7 Emergency HVAC response is available for breakdowns that can’t wait until Monday morning.
San Diego Neighborhoods We Regularly Service for RTU Work
We handle 24 Hour HVAC Service Near Me in San Diego, CA across the full metro area. Some of our most frequent commercial service stops include Kearny Mesa, where the density of light industrial and office parks means we often run two or three RTU calls in a single day; Mission Valley, where older commercial buildings have RTUs pushing 15 or 20 years of age; Sorrento Valley and Miramar for tech and logistics facilities; and Chula Vista and National City for the growing commercial corridor along Bay Boulevard. We’re also regularly on rooftops in North Park, Hillcrest, and Bankers Hill for smaller commercial buildings and mixed-use properties.
Rooftop Unit Maintenance: Preventing the Emergency Call
Most RTU failures we respond to in San Diego were preventable. Coils that haven’t been cleaned in two or three San Diego summers accumulate a combination of dust from the inland desert winds and salt residue from marine air – a combination that insulates coil fins and steadily chokes airflow until the compressor starts struggling. Belts and bearings that go uninspected crack and seize. Condensate drains that aren’t cleared back up and trip safety switches.
An Annual Maintenance contract – one visit before the summer cooling season and one heading into winter – typically catches these issues for a fraction of what emergency repairs cost. We offer maintenance agreements for commercial clients across San Diego that include coil cleaning, electrical checks, refrigerant verification, filter replacement, and a written condition report. Building managers who want predictable HVAC costs rather than surprise breakdowns find this the most practical option.
FAQs – Rooftop Unit Repair in San Diego
How long does a rooftop unit last in San Diego’s climate?
A commercial RTU in San Diego typically lasts 12 to 18 years with regular maintenance, though coastal locations can shorten that by two to four years due to accelerated corrosion on coils and electrical components. Units in areas like Ocean Beach or Coronado that sit in salt-air exposure without annual coil cleaning often show significant degradation by year ten. If your RTU is approaching 15 years old and needs a major repair like a compressor, replacement is often the smarter financial move. Call (844) 875-9451 and we’ll give you an honest read on where your unit stands.
Can you repair a rooftop unit the same day in San Diego?
Same-day repair is possible for most common failures – contactors, capacitors, fan motors, and refrigerant issues – because we carry those parts on the truck. Compressors and control boards may require a parts order, but we can usually source and install within 24 to 48 hours for most major RTU brands including Goodman and Rheem. For urgent commercial situations, call us directly at (844) 875-9451 and we’ll tell you upfront what’s realistic based on your unit’s brand and the part needed.
Is it better to repair or replace an aging rooftop unit?
Repair makes sense when the unit is under 12 years old, the repair cost is less than 40 to 50 percent of replacement cost, and the rest of the system is in reasonable condition. Beyond that window, especially if you’re also facing refrigerant issues with older R-22 units or corrosion damage in multiple components, replacement usually delivers better economics within two to three years through energy savings and avoided repeat repairs. Gregory Hahn will give you both numbers side by side so you can make the call with full information, not sales pressure.
Do you service rooftop units from all major brands?
Yes. Redwood Heating & Air services RTUs from Trane, Lennox, Rheem, Goodman, and several other major manufacturers. Multi-brand experience matters more for RTUs than for residential equipment because commercial buildings often have units from different eras and manufacturers on the same roof. We don’t steer you toward one brand because that’s the only one we know – we diagnose what you have and recommend what’s right for your building. Call (844) 875-9451 to confirm compatibility before scheduling if you have a less common unit brand.
Key Takeaways
- Rooftop unit failures in San Diego are often driven by the city’s combination of marine air, inland heat, and deferred maintenance – not just equipment age.
- Redwood Heating & Air has 13 years of commercial RTU experience across San Diego, led by Gregory Hahn, a Master Technician who is on the job, not in an office.
- We service units from Trane, Lennox, Goodman, Rheem, and other major brands – so brand isn’t a barrier to getting the right diagnosis.
- Repair costs range from around $180 for a simple component swap to $2,800+ for compressor work; full replacement typically runs $5,500 to $14,000+ depending on tonnage.
- Most RTU emergencies we respond to were preventable with semi-annual maintenance. We offer commercial maintenance agreements across San Diego.
- Estimates are free. We price in writing before any work starts.
Schedule Rooftop Unit Service in San Diego
If your rooftop unit is struggling, locked out, or simply hasn’t been serviced in the past year, now is the right time to get eyes on it – before the next San Diego heat stretch turns a maintenance issue into an emergency repair. Redwood Heating & Air serves commercial clients across San Diego from Chula Vista to Sorrento Valley, and we’re built for exactly this kind of work. Call (844) 875-9451 to schedule a diagnostic or request a free estimate on a replacement. Gregory Hahn and the Redwood team will give you a straight answer and a fair price, not a sales pitch.
You can also learn more about the full range of services we provide under our home page, or explore the complete scope of our commercial work on our Emergency & Commercial HVAC in San Diego page.
Written by Gregory Hahn, Founder & Master Technician at Redwood Heating & Air San Diego, serving San Diego since 2012.