Residential · Oakland, CA · 2026
Carlton St, Oakland: two gas furnaces replaced with ducted heat pumps
Two gas furnaces, one in the attic and one in the crawlspace, replaced with two independent Mitsubishi ducted heat pumps on the existing ductwork.
This Oakland home was heated by two gas furnaces: one in the attic for the upper floor and one in the crawlspace for the lower floor. The ductwork was in good condition, so we kept it and swapped each furnace for its own Mitsubishi ducted heat pump. Each floor now has its own outdoor unit, air handler and thermostat, with heating and cooling from one system per floor and no gas combustion.
- Type
- Heat Pump Conversion
- Client
- Residential homeowner
- System
- Two Mitsubishi ducted heat pumps (2-ton attic, 2.5-ton crawlspace)
- Location
- Oakland, CA · 2026
Scope
- — Removed both gas furnaces; capped the gas lines and flues
- — Mitsubishi SVZ-AP24NL air handler in the attic, matched to an SUZ-AA24NL outdoor unit (2 tons)
- — Mitsubishi SVZ-AP30NL air handler in the crawlspace on a strut and threaded-rod platform, matched to an SUZ-AA30NL outdoor unit (2.5 tons)
- — New supply and return plenum transitions and filter access at both air handlers, tied into the existing duct systems
- — Pre-insulated refrigerant line sets and communication wiring; about 70 ft for the upper system and 25 ft for the lower
- — Paintable exterior line-hide for the upper system and a wall penetration cover at the crawlspace entry
- — Attic: secondary drain pan with float switch, PVC condensate to the exterior. Crawlspace: condensate pump with safety switch
- — Both outdoor units on wall-mounted brackets with structural anchorage
- — Two dedicated 30A/240V circuits with fused disconnects by our licensed electrical subcontractor
- — Pressure test, evacuation, decay test, charge verification, startup and commissioning
- — Two Mitsubishi kumo touch (MHK2) wireless thermostats, one per floor
Constraints
- — Occupied home: floors and finishes protected and daily cleanup
- — Equipment split between a tight attic and a crawlspace
- — Long line-set run (about 70 ft) to the upper outdoor unit
- — Main electrical panel already carries a solar interconnection
3rdGen's Role
3rdGen sized and specified both systems, pulled the City of Oakland mechanical and electrical permits, installed both heat pumps, coordinated the electrical work and commissioned each system. City of Oakland mechanical and electrical permits pulled by 3rdGen.
Outcome
Both gas furnaces are gone. The house runs on two independent R-454B heat pumps, so each floor heats and cools on its own schedule from its own thermostat.
Photography
