Lennox HVAC in Hillsborough, CA | Stonegate Heating & Air California
Lennox HVAC service in Hillsborough typically runs $150–$650 for repairs and $3,500–$7,500 for full system replacement, with most calls completed same-day. What makes our work here different is simple: Hillsborough’s all-residential zoning means every job is a custom estate, and we’ve spent 16 years learning how Lennox equipment behaves in 10,000 sq ft homes with 1960s ductwork and city inspectors who know exactly what to look for. Call (855) 467-1888 for a free estimate.
Why Hillsborough Residents Choose Us for Lennox Service
We’ve worked on Lennox systems in Hillsborough long enough to recognize the sound of an SL28XCV blower struggling against an undersized return drop before we even open the attic hatch. Jason Trent, our owner and Field Supervisor, grew up in the San Fernando Valley and spent summers without reliable AC — he took HVAC coursework at Los Angeles Trade-Technical College specifically so he’d never have to guess why a system was failing. That background shows up in how we diagnose.
Our crew carries OEM Lennox filters, capacitors, and circuit boards for Signature Series and Merit models on every truck. In Hillsborough, that matters more than it might elsewhere. The city’s building department doesn’t mess around with permit compliance, and a callback because we guessed wrong on a part number costs us a full day with an inspector. We’d rather stage it right the first time.
We’re an independent Lennox service provider, not a factory-authorized dealer. That distinction matters to homeowners who’ve been told their warranty is void unless they use a specific shop. We use OEM parts where they matter, quality aftermarket where cross-referencing is proven, and we tell you which is which before we start. No secrets.
Nearly 500 reviews at 4.7 stars over 16 years. Jason still shows up on the bigger jobs himself. The system will tell you what’s wrong — you just have to know how to listen.
Common Lennox HVAC Problems We Solve in Hillsborough
- Signature Series blower module thermal overload. The SLO and SL28XCV variable-speed blowers weren’t designed for the return-air starvation common in Hillsborough’s expanded 1950s–70s homes. When a 6,500 sq ft house still breathes through a 12×20 grille meant for 2,800 sq ft, the blower motor works harder, runs hotter, and fails within 18 months. We measure static pressure before we quote any replacement.
- Merit ML14 high-pressure lockouts on south-facing lots. Hillsborough’s estate setbacks often squeeze condensers between concrete walls and landscaping berms. On 80°F afternoons, that trapped radiant heat pushes discharge pressures past the ML14’s safety threshold. We’ve replaced three of these in the past two years on properties near Crystal Springs Road where the pad placement was an afterthought.
- Elite EL18XCV reversing valve solenoid failure. Spring fog rolling off the ridgeline doesn’t burn off as fast here as it does in Burlingame. Moisture degrades the solenoid coil insulation over 2–3 years, and the valve sticks open. Heat pump switches to cooling in January. Homeowner notices when the master bedroom hits 58°F.
- Merit ML18 heat exchanger cracking in finished attics. Hillsborough’s 1940s–60s custom homes often have sealed, conditioned attics that were retrofitted without combustion air calculations. The ML18 draws its own makeup air until it can’t, then the exchanger runs hot and cracks prematurely. We’ve found this three times on homes south of El Cerrito Avenue.
- Refrigerant undercharge in multi-zone retrofits. Homeowners add 2,000 sq ft and a second Lennox zone, but the original lineset was sized for half the load. Subcooling runs low, superheat climbs, and the TXV hunts. We catch this with a proper Manual J and refrigerant weight verification — not a pressure reading alone.
Lennox Service in Hillsborough: What Local Conditions Mean for Your Equipment
Hillsborough’s all-residential zoning means every HVAC job is on a custom estate lot. There are no apartment complexes, no strip-mall RTUs, no quick in-and-outs. Every Lennox Signature Series install we do requires a dedicated building permit and Manual J load calculation because the city’s building inspectors review all mechanical work, and they’re known to flag undersized return duct chases or missing seismic gas shut-offs that other Peninsula cities overlook.
This changes how we bid jobs. In San Mateo or Burlingame, an unpermitted equipment swap might slide through if the homeowner doesn’t pull a permit. In Hillsborough, it won’t. Inspectors here have seen enough $50,000 system replacements to know when a return drop is sized for the original 1940s footprint instead of the current 12,000 sq ft. We’ve had to halt work mid-project when a previous contractor skipped the permit, and the homeowner ends up paying for demo and re-do. We don’t start without the permit in hand.
That same zoning reality means every comfort complaint is a zoned-system problem. A 10,000 sq ft home with a single thermostat will never balance. The south-facing great room runs 5°F warmer than the north wing even on mild days. Lennox’s variable-capacity SL28XCV was built for exactly this, but only if the ductwork and zoning controls are engineered to match. We treat Hillsborough as a multi-zone market by default.
Lennox Models & Products We Service in Hillsborough
We work on the full Lennox residential line: Signature Series including the SLO oil furnace, EL18XCV and SL28XCV variable-capacity air conditioners; Merit Series ML14 and ML18 single-stage and two-stage systems; Elite Series EL16 and EL22 mid-tier units; and the XP25 variable-capacity heat pump.
Our trucks stock OEM Lennox air conditioning contactors, defrost boards, and gas valves sourced through local distributors. For capacitors and condenser fan motors, we cross-reference proven aftermarket equivalents and disclose the option. Our flat-rate pricing includes a replacement threshold: if the failed part is under $150 and the system is under 15 years old, we’ll repair. Older than that, we recommend replacement. We’ve seen too many homeowners throw $400 at a 20-year-old Merit Series only to replace it 18 months later.
For Hillsborough’s larger homes, we emphasize multi-zone system design, proper AC installation with load-matched equipment, and refrigerant recharge services when expansions have thrown off the original charge. Lennox sales & service is one of nine brands we cover, but it’s a significant share of our Hillsborough work.
Lennox Service Pricing in Hillsborough
| Service | Price Range |
|---|---|
| AC Repair | $150–$650 |
| Furnace Repair | $150–$700 |
| AC Installation | $3,500–$7,500 |
| Tune-Up | $80–$200 |
What drives cost on a Lennox system in Hillsborough isn’t the equipment alone. It’s the permit process, the duct modification to serve expanded square footage, and the electrical upgrades that 1960s panels often need before they’ll support a variable-capacity compressor. Our free estimate includes a full load calculation, static pressure test, and permit application prep. We don’t guess.
Call (855) 467-1888 for an exact quote. Estimates are free, and we can usually schedule within 48 hours.
Serving Hillsborough, CA — Our Local Coverage Area
We’re based in the Hillsborough area and know this community well. Use the map below to see our service coverage — if you’re nearby, we can almost certainly help.
FAQs — Lennox HVAC in Hillsborough
Yes. Hillsborough requires a permit for all mechanical equipment replacement, and inspectors verify combustion air, seismic gas shut-off valves, and duct sizing. We handle permit application and plan submission as part of our installation package. Call (855) 467-1888 and we’ll walk you through the timeline.
Usually not without modification. Original ductwork in Hillsborough’s expanded estates was sized for 2,500–4,000 sq ft, not the current 8,000–12,000. We measure static pressure and design a new return drop or zoned distribution before specifying equipment. On El Cerrito Avenue, we replaced a 12×20-inch return with a 24×30-inch filtered media cabinet to serve a 6,500 sq ft home — the owners had consistent 72°F comfort across four zones for the first time since the addition was built.
Most residential replacements take 2–3 days of field work, plus permit approval time. Hillsborough’s plan check typically runs 5–10 business days for mechanical permits. We don’t start demo until the permit is issued. Rushing this step has cost other contractors mid-project shutdowns.
Yes. The SL28XCV and SLO blower modules are sensitive to return-air restriction, and Hillsborough’s expanded homes often have original return drops that are half the size the current square footage requires. Static pressure climbs above 0.5 inches WC, the motor overheats, and the module faults out. We measure this with a manometer, not a guess. Call (855) 467-1888 — we’ll diagnose it in one visit.
We can repair and recharge R-22 systems using reclaimed refrigerant, but we don’t install new R-22 equipment. If your system is leaking or the compressor has failed, replacement with an R-410A or newer refrigerant system is the practical path. We factor Hillsborough’s permit requirements and electrical panel capacity into that recommendation.
Service Areas Near Hillsborough
We run Emergency & Commercial HVAC in Hillsborough and surrounding Peninsula communities. Our regular service radius includes Lennox service in San Carlos to the north, Burlingame and San Mateo along the 101 corridor, and Lennox service in Orangevale for homeowners with secondary properties in the Sacramento area. We also cover West Covina, Vista, Sacramento, San Leandro, Valinda, and Baldwin Park through our extended dispatch network.
Book Your Lennox Service in Hillsborough Today
Call (855) 467-1888 for same-day or next-day Lennox service in Hillsborough. Jason Trent or one of our senior techs will walk through what you’re seeing, check our stock for your model, and schedule a free estimate if replacement makes sense. We’ve been at this 16 years. We’d rather earn the call than talk you into it.
Written by Jason Trent, Owner and Field Supervisor at Stonegate Heating & Air California, serving Hillsborough and the Peninsula since 2008.