Berkeley, CA
Religious Institution Mechanical Upgrade | Berkeley
- Commercial
- Institutional
- Berkeley
- Existing Building Upgrade
Accessory dwelling units
ADU HVAC
3rdGen supports HVAC for ADUs, garage conversions, additions, and small permitted residential structures where comfort, code, equipment placement, and space constraints matter. ADU projects often benefit from compact heat pump or ductless solutions, depending on layout and project goals.
Approach
Sized for the new envelope
ADUs and additions need independent, right-sized mechanical systems — not extensions of an existing furnace that was never designed for the extra load. We design standalone scopes with load calculations, equipment that fits tight spaces, and coordination with your builder or architect.
What's included
Design-build scope
- Manual J sizing for the ADU or addition envelope
- Compact ducted or ductless heat pump options
- Coordination with ADU builder, architect, or GC
- Separate zoning from the main house where required
- Permit and Title 24 documentation
- Electrical coordination for new panel or sub-panel loads
Our Field Projects
Real Bay Area homes, engineered and installed.
View all projects → 
Berkeley, CA
Hearst Remodel — Berkeley
- High-End Residential HVAC
- Residential Remodel HVAC
- Ductless Multi-Zone Systems
- Heat Pump Systems
Berkeley, CA
San Pablo Ave Retail TI — Berkeley
- Commercial HVAC
- Commercial Tenant Improvement
- Berkeley Commercial HVAC
- Mitsubishi Multi-Zone System
Process
How a project moves
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01
Tell us about your home
Share location, timeline, plans if you have them, and what is not working today — or what your builder has scoped.
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02
Size & design the system
We use Manual J, S, and D where the project needs it to match equipment, ducts, and zoning to the actual house.
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03
Coordinate & install
Principal-led field work with your GC or architect around access, finishes, sequencing, and clean rough-in.
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04
Startup & handoff
System startup, basic orientation, and documentation so you know how the new system is meant to run.
Related
Explore more
Common Questions
Common questions
Can my existing furnace handle the ADU?
Usually not without engineering analysis — and even when possible, it rarely delivers good comfort or efficiency. We design independent systems sized for the ADU itself.
Do you work on prefab ADU packages?
Yes, with builders and homeowners who need mechanical design, permit coordination, and installation beyond a generic mini-split spec.
What about noise for adjacent neighbors?
Equipment placement, line-set routing, and product selection all affect noise. We plan outdoor unit location and indoor distribution with ADU siting in mind.