Whether your old furnace has finally given out or you're upgrading to a high-efficiency system, SF HVAC Repair handles every aspect of furnace installation in San Francisco — from equipment selection and BAAQMD compliance to SFDBI permits and final inspection coordination.
San Francisco's mild but persistently damp climate makes furnace sizing and efficiency selection different from most California cities. The city sees relatively few extreme cold days, but the combination of marine layer humidity, coastal fog, and temperatures that can feel much colder than the thermometer indicates means that reliable, right-sized heating is essential for comfort. An undersized furnace runs constantly and still can't warm the house; an oversized furnace short-cycles and wastes energy on every heating cycle.
SF HVAC Repair installs and replaces furnaces across San Francisco's residential housing stock — from compact 40,000 BTU systems in Victorian flat bedrooms to 100,000 BTU whole-home systems in larger Richmond or Sunset District homes. We work with leading furnace brands: Carrier, Lennox, Rheem, Amana, American Standard, and Daikin. We also install Carrier Performance and Infinity series and Lennox Dave Lennox Signature series high-efficiency systems.
Every furnace installation begins with a free in-home load calculation using Manual J methodology — the ACCA-certified approach to determining the correct furnace size. We also assess your existing ductwork for leaks and restrictions, inspect your gas supply line capacity, evaluate your electrical service, and identify any code compliance issues that need to be addressed before the new system goes in. Ductwork replacement is quoted separately after we inspect the location and access. Ducts routed through an SF garage may require rigid metal ductwork, which is more involved than accessible runs. This upfront investment in engineering is what separates a proper installation from a swap-and-go job that leaves you with an incorrectly sized or non-compliant system.
Furnace selection is not just about the brand name. AFUE describes how efficiently a furnace converts fuel into usable heat, while heating stages, blower control, and modulation determine how precisely it delivers that heat to your rooms. We compare these options as part of every Manual J-based furnace replacement estimate.
Standard-efficiency, non-condensing furnaces use a metal flue to vent combustion gases. They can be a practical replacement where compatible venting is already in place and budget is the primary concern.
High-efficiency condensing furnaces recover additional heat from the exhaust stream. They require a condensate drain and manufacturer-approved sealed venting, but can lower fuel use and support advanced comfort features.
Single-stage models have one heating setting: full output. They offer straightforward operation and are often a fit when a simple replacement is the priority.
Two-stage furnaces use a lower firing level for most mild San Francisco days and a higher level when temperatures drop. Longer low-stage cycles can help keep room temperatures more even.
A variable-speed blower adjusts airflow instead of operating at one fixed speed. With compatible equipment and ductwork, it can provide steadier airflow, quieter starts, and improved comfort.
Modulating furnaces adjust gas output in small increments to follow the home's heat demand. They are the most precise gas-furnace option and work best with proper sizing and a compatible thermostat.
| Efficiency Rating | Annual Gas Savings vs. 80% | Best For |
|---|---|---|
| 80% AFUE | Baseline | Budget replacement, older duct systems |
| 90% AFUE | ~12% | Mid-tier upgrade, moderate use homes |
| 96%+ AFUE | ~20% | Maximum efficiency, longest payback |
Furnace installation in San Francisco requires navigating two regulatory bodies: the San Francisco Department of Building Inspection (SFDBI), which issues the mechanical permit, and the Bay Area Air Quality Management District (BAAQMD), which regulates combustion equipment emissions. Low-NOx and ultra-low-NOx furnaces use burner designs that reduce nitrogen oxide emissions compared with older equipment; ultra-low-NOx is the lower-emissions category of the two.
We handle the SFDBI permit and verify the applicable BAAQMD equipment requirements before installation. We schedule the required SFDBI final inspection and document the completed work for your records.
We install and replace furnaces in all 28 SF neighborhoods.