Fast, Reliable Heating & Furnace Across San Lorenzo
Heating and furnace repair in San Lorenzo typically runs $150–$700 for repairs, $3,500–$7,500 for full replacement, and most calls to the 94580 ZIP are handled same day or next day. We’re familiar with the unique challenges of San Lorenzo’s mid-century Bohannon tract homes, where original floor furnaces and wall heaters still outnumber central forced-air systems by a wide margin. Call us at (844) 875-9451 for a free estimate.
San Lorenzo sits in Alameda County’s flatlands, caught between the cooling marine influence and inland heat spikes that can push summer afternoons past 95°F while nights drop to the low 60s. That 30–40°F diurnal swing, combined with housing stock built between 1944 and 1960 that was never designed for central HVAC, creates furnace problems you won’t find in newer East Bay communities. Our Heating & Furnace team has spent 13 years solving these exact retrofit puzzles.
Why Redwood Heating & Air San Diego Is San Lorenzo’s Preferred Heating & Furnace Company
Gregory Hahn founded this company and still leads every technical decision. That matters in San Lorenzo, where a furnace replacement isn’t a swap—it’s a structural retrofit requiring master-level planning around slab foundations, minimal attic clearance, and Alameda County’s unincorporated permit process.
We’ve earned 428 verified reviews averaging 4.6 stars over 13 continuous years. San Lorenzo customers specifically mention our ability to navigate county permits (not city permits, which trip up contractors used to working in neighboring incorporated cities like San Leandro) and our familiarity with the identical floor plans that repeat block after block in the 94580 ZIP.
Our response time to San Lorenzo is typically same-day for emergency calls, next-day for standard appointments. We keep common Bryant, Carrier, and Trane furnace components stocked for faster turnaround on repairs.
Here’s what separates us: most HVAC companies in the East Bay train on one or two brands and dispatch crews with limited retrofit experience. Gregory Hahn holds a Master Technician designation and has factory-level experience across nine major brands. In San Lorenzo, that means we can service whatever wall heater or floor furnace you’re stuck with now, then design a replacement system that actually fits your home’s constraints.
Our Heating & Furnace Services in San Lorenzo
Furnace Repair
Furnace repair in San Lorenzo usually means one of three things: a failed ignitor on an original wall heater, a gas valve that won’t open on a 1960s floor furnace, or a cracked heat exchanger venting carbon monoxide into the living space. We see all three weekly in the Bohannon tracts. A typical repair runs $150–$700 depending on whether we’re sourcing a scarce vintage part or replacing a standard component on a newer system. If your floor furnace is original to the house, we’ll test the heat exchanger with a combustion analyzer before any other work—cracked exchangers are common enough in 94580 that we don’t take chances.
Furnace Replacement
Full furnace replacement in San Lorenzo is where our retrofit expertise shows. These homes weren’t built with mechanical chases or dedicated duct runs. We recently replaced a 1958 in-floor gas furnace on Via Alamosa with a high-efficiency Carrier gas furnace and custom flex-duct system, threading supply runs through the minimal attic and sealing every seam to meet Alameda County’s permit requirements—eliminating the CO risk from the cracked original heat exchanger. Replacement costs run $3,500–$7,500 depending on whether we can use existing infrastructure or need to build custom plenums and external chase boxes. Slab-on-grade foundations and shallow attics make ductwork installation impossible without experienced retrofitters.
Furnace Tune-Up
A furnace tune-up in San Lorenzo runs $80–$200 and pays for itself fast in these older systems. We focus on combustion analysis, gas pressure verification, and heat exchanger inspection—especially critical for original floor furnaces still operating in the interior blocks of 94580. The minimal insulation in these homes means a poorly tuned furnace works harder and burns more gas than necessary. We also check for proper venting, since many wall heaters and floor furnaces rely on natural draft that can fail in the Diablo wind events that hit San Lorenzo each September and October.
Heat Exchanger Inspection & Replacement
Heat exchanger failure is the most serious problem we encounter in San Lorenzo’s original floor furnaces. A cracked exchanger allows combustion gases, including carbon monoxide, to mix with heated air distributed through the home. We find this condition regularly in 1950s units still operational in the Bohannon tracts. Replacement exchangers for these vintage systems are essentially unavailable, so we typically recommend converting to a modern forced-air furnace with proper ductwork. This isn’t a scare tactic—it’s a measured response to equipment that has exceeded its safe service life by decades. We’ll show you the crack with a borescope camera and explain your options without pressure.
Gas Valve Repair
Gas valve failures on original wall heaters and floor furnaces are increasingly common as components age past 60+ years. The problem: replacement valves for many of these units are obsolete. We carry universal gas valves that can be adapted to older equipment, but in San Lorenzo we often find that a failed valve is the final straw that pushes homeowners toward full furnace replacement. If your wall heater cycles erratically, won’t maintain temperature, or smells of gas at startup, shut it off and call us. We’ll diagnose whether a repair is feasible or if it’s time to discuss conversion to a modern system.
What happens when you call
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A real person answersNo phone trees — you reach a local pro.
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You get an upfront price rangeHonest numbers before anyone is dispatched.
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A background-checked tech heads outLicensed & insured, dispatched right away.
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You approve before work beginsNothing starts until you say go.
Trusted Brands We Service in San Lorenzo
We service and install Carrier, Trane, Bryant, and American Standard furnaces, among others. Our multi-brand fluency matters in San Lorenzo because many homeowners converting from floor furnaces or wall heaters are starting fresh with no existing equipment to match. We can recommend the right unit for your home’s heat load and physical constraints, not just sell whatever brand we happen to stock. For the Diablo wind corridor’s temperature swings, we often specify two-stage gas valves and variable-speed blowers that can modulate output rather than cycling full-on, full-off. We keep common Bryant and Carrier repair parts on our trucks for faster resolution of San Lorenzo service calls.
Common Heating & Furnace Problems We See in San Lorenzo Homes
- Cracked heat exchangers in original floor furnaces. These 1950s units embedded in subfloors throughout 94580 have exceeded their design life by decades. We find cracked exchangers that pose active carbon monoxide risks, requiring immediate system shutdown and conversion planning.
- Failed ignitors and obsolete gas valves on wall heaters. Original wall heaters in the Bohannon tracts fail repeatedly as components age out of availability. Scarcity of replacement parts often forces the decision to retrofit rather than repair.
- Undersized or leaky ductwork from inexperienced retrofits. Slab-on-grade foundations and shallow attics make proper duct installation challenging. We’ve corrected numerous San Lorenzo jobs where previous contractors installed ducts too small for the heat load or failed to seal seams, bleeding efficiency.
- Combustion safety issues from natural draft venting. Many original systems rely on gravity venting that can backdraft during Diablo wind events or when bathroom fans create negative pressure. We test every system for proper draft and spillage.
Pricing for Heating & Furnace in San Lorenzo, CA
Here’s what furnace work costs in the San Lorenzo market:
| Service | Price Range |
|---|---|
| Furnace Repair | $150–$700 |
| Furnace Replacement | $3,500–$7,500 |
| Furnace Tune-Up | $80–$200 |
Replacement costs vary based on whether your Bohannon home needs custom ductwork, external chase boxes, or if we can thread supply runs through existing attic space. Alameda County permit fees are separate and typically modest for furnace replacements. We provide itemized written estimates before any work begins. Call (844) 875-9451 for a free, no-obligation quote.
We Also Serve Cities Near San Lorenzo
Our service area extends throughout the East Bay flatlands, including Ashland, San Leandro, Cherryland, and Castro Valley. Each community has distinct housing stock and permit requirements—San Leandro’s incorporated status means city permits, not county, while Castro Valley’s hillside homes present different ductwork challenges than San Lorenzo’s slab-on-grade tracts. We adjust our approach accordingly.
Serving San Lorenzo, CA — Our Local Coverage Area
We’re based in the San Lorenzo 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 — Heating & Furnace in San Lorenzo
The Bohannon Organization built nearly all of San Lorenzo’s housing stock between 1944 and 1960 with floor furnaces or wall heaters as standard equipment, and central forced-air retrofits weren’t common until recent decades. Many homeowners have maintained these units past their safe service life because replacement requires significant structural modification. If your floor furnace is original, we strongly recommend a combustion safety inspection to check for cracked heat exchangers. Call (844) 875-9451 to schedule—estimates are free.
Yes. Because San Lorenzo is unincorporated Alameda County rather than an incorporated city, all furnace replacements require permits through the Alameda County Building Department, not a city building department. This procedural distinction trips up contractors who primarily work in neighboring incorporated cities. We handle the permit application and inspection scheduling as part of our replacement service. Call (844) 875-9451 and we’ll walk you through the timeline.
Even homes with minimal or no usable attic space can accommodate ductwork through creative routing. We use custom plenums, external chase boxes, and sealed flex-duct runs that can thread through closets, soffits, or exterior bulkheads. We recently replaced a 1958 in-floor gas furnace on Via Alamosa with a high-efficiency Carrier gas furnace and custom flex-duct system, threading supply runs through the minimal attic and sealing every seam to meet Alameda County’s permit requirements. Every Bohannon home we’ve worked on has yielded a workable solution. Call (844) 875-9451 for a site-specific assessment.
We typically specify Carrier, Trane, or Bryant two-stage or modulating furnaces for San Lorenzo homes, as these systems can adjust output to match the 30–40°F diurnal swings common in the East Bay flatlands. Single-stage furnaces cycle full-on, full-off, creating temperature stratification and wasted energy. Variable-speed blowers also improve air filtration during the hot, dry Diablo wind events that spike particulate levels each fall. We’ll match the specific model to your home’s heat load calculation, not sell you more capacity than you need.
Yes, if your floor furnace is aging or has safety issues. A modern gas furnace with ductwork provides more even heating, better air filtration, and the infrastructure for future AC addition if desired. In San Lorenzo’s climate, where summer afternoons can hit 95–100°F during inland heat pushes, many homeowners who convert for heating later add cooling. The conversion also eliminates the carbon monoxide risk from cracked floor-furnace heat exchangers. We can phase the work if budget is a concern. Call (844) 875-9451 for a free estimate on conversion options.
Ready to solve your heating problem? Call (844) 875-9451 for a free estimate. We’ll diagnose your system, explain your options in plain language, and get your San Lorenzo home warm and safe.
Written by Gregory Hahn, Owner at Redwood Heating & Air, serving San Lorenzo since 2011.