Residential HVAC · Mill Valley, CA
3rdGen designs and installs whole-home heat pump systems for Mill Valley remodels, retrofits, and technically involved residential projects — including ducted systems, multi-zone equipment, ventilation, load calculations, and coordination with architects and builders.
Remodels · Retrofits · Heat Pumps · Multi-Zone Systems
Project Inquiry
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Project fit
This page is for substantial residential work in Mill Valley — whole-home upgrades, conversions, remodels, and multi-zone systems that need real design-build planning, not quick equipment swaps or service calls.
New system
New ducted or ductless heat pump systems sized for your home, comfort goals, and how the house is built.
Heat pump installationFull upgrade
Replace aging furnace and AC together, or convert gas heat to a heat pump with ducts, electrical scope, and controls planned as one job.
Replacement & conversionCentral
Central heating and cooling through existing or updated ductwork, with loads and airflow checked before equipment is selected.
Ducted heat pumpsRoom-by-room
Mini-splits and multi-zone layouts when zoning, architecture, or tight routing make ductless or mixed systems the better fit.
Ductless & multi-zoneCoordinated
Mechanical design and rough-in coordinated with your architect or builder while walls and ceilings are still open.
HVAC for remodelsFresh air
ERV/HRV, filtration, and balanced ventilation coordinated with your heating and cooling scope when the project needs it.
Ventilation & IAQProject proof
High-end residential remodel
GC-led residential remodel with a six-zone ductless heat pump system and two outdoor units — representative of the remodel and retrofit work we deliver across the Bay Area, including design-sensitive existing homes.
The six-zone Fujitsu ductless system was installed, permitted, inspected, and completed as part of the home’s remodel-for-sale scope — delivering zoned heating and cooling without a conventional ducted retrofit.
Representative published remodel scope — location, photos, and full details on the project page.
View projectBuilt around the house
Existing homes in Mill Valley can introduce constraints that are not solved by simply choosing equipment. Ductwork, site access, outdoor-unit location, property-line sound, architecture, and remodel conditions can all shape the system.
3rdGen evaluates the home as one mechanical system — load, distribution, zoning, equipment location, ventilation, routing, access, and serviceability — before locking in an approach.
Existing construction can require more thought around duct reuse, distribution, zoning, and equipment locations.
Heat-pump placement needs to consider access, appearance, setbacks, serviceability, and property-line sound requirements.
When walls and ceilings are open, early HVAC coordination protects ceiling heights, millwork, and service access.
Site access and limited equipment locations can influence system layout and installation planning.
Mill Valley permitting note: outdoor heat-pump equipment location and property-line sound must be addressed during the mechanical permit process, so equipment siting should be considered early.
Homeowner reviews
207 Google reviews
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Mitsubishi mini-split installed with outstanding care. Indoor and outdoor units done right. High efficiency meant a meaningful federal tax credit too.
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Devin and his crew did a fantastic job installing AC for our whole house. High quality Mitsubishi equipment and a clean installation throughout.
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Devin is meticulous, methodical, and knowledgeable. Professional crew and a heat pump install we trust completely.
Photos from the installs above
Read all 207 reviewsHow we work
On many Mill Valley projects, the important decisions happen around the home, the remodel, and the site — not from copying the equipment that came out.
Plans, goals, existing system, remodeling scope, and known constraints.
Manual J / system sizing where appropriate, zoning strategy, equipment selection, and distribution.
Indoor equipment, outdoor equipment, duct / refrigerant routing, ventilation, access, and serviceability.
Outdoor-unit location, property-line sound considerations, GC/architect coordination, and permit requirements.
Rough-in and finish installation coordinated around the project.
Startup, controls, commissioning checks, inspection coordination, and homeowner handoff.
Complete project delivery
A Mill Valley electrification project can touch the furnace, ducts, electrical service, controls, equipment locations, permits, and finished interiors. We plan those connections as one scope.
The result is a complete system designed for the home, installed to the plan, and tested before handoff.
Tell us about the projectRemoval and replacement planned around the complete conversion.
Reused, modified, or replaced according to what the design requires.
Capacity, circuits, documentation, inspections, and other trades coordinated with the HVAC scope.
Operation and airflow checked before the project is handed back to you.
Cost
Based on recent 3rdGen projects, most residential heat pump installations fall within the ranges below. Final pricing follows evaluation of the building, load, ducts, electrical scope, and site conditions — including duct condition, zoning, remodel complexity, equipment access, hillside access, routing, outdoor siting, sound constraints, ventilation, and finish coordination.
Complex whole-home and design-build projects can exceed these ranges. Current heat-pump rebates or incentives may apply depending on the home, utility account, equipment, and program eligibility — see /residential/rebates/ for an overview. We do not guarantee specific savings amounts.
Project inquiry
Share your ZIP, the home, plans if you have them, and your timeline. A project lead reviews the scope and follows up — no call center, no dispatcher.
Project Inquiry
Thanks — your project details are on their way to 3rdGen. We’ll review them and follow up about the next step.
Project teams
Many of 3rdGen’s strongest residential projects are builder- or architect-led. Early mechanical coordination can protect ceiling space, equipment access, visible finishes, duct routes, outdoor-unit locations, and the construction schedule.
We work within existing project teams in Mill Valley and across Marin — or directly with homeowners when that is the right path.
Mechanical systems coordinated around architecture, ceiling conditions, equipment locations, routing, and finish requirements.
Explore HVAC for architectsClear scope, scheduling, rough-in coordination, submittals, inspections, startup, and project handoff.
Explore HVAC for builders & GCsField execution, equipment selection, controls coordination, submittals, installation, and commissioning aligned with the mechanical design.
Explore engineering coordinationAlready assembling your own project team? We can take ownership of the mechanical scope and coordinate directly with the other professionals involved.
Start a residential projectMitsubishi Electric
As a Mitsubishi Electric Diamond Contractor, we design and install ducted, ductless, and multi-zone systems for Bay Area homes, with factory-trained crews and longer warranty options on qualifying residential installs.
Mitsubishi is not automatically the answer to every home. We start with what the project requires and recommend the system that makes sense.
12 Year Parts &
Compressor Warranty
Extended parts & compressor coverage on qualifying Diamond installations.
Ongoing manufacturer training on the latest hyper-heat systems.
Direct factory escalation if anything ever needs attention.
FAQ
Straight answers on heat pumps, Mill Valley permits, remodel coordination, and whole-home HVAC scope.
Most heat-pump and A/C installations require a mechanical permit through the City of Mill Valley. Required submittals typically include a site plan showing exterior equipment, manufacturer specifications, and calculations addressing equipment sound at property lines — exact requirements depend on scope and are subject to City review.
Permit applications generally need the proposed exterior equipment location on a site plan, equipment specs, and sound calculations at property lines. Setbacks and other zoning conditions also apply depending on the property. We plan placement and documentation around those requirements without promising a specific review outcome.
Yes. On many projects, existing homes introduce questions around ducts, zoning, electrical capacity, and equipment access. Ducted, ductless, or mixed heat pumps can fit when the design starts with the house — not a catalog default.
Sound at the property line is part of Mill Valley’s mechanical permit review. Equipment selection, location, and mounting can all influence results. We evaluate placement early so sound and access are part of the design — not a surprise after equipment is ordered.
It depends on existing ducts, ceiling space, zoning goals, and how the remodel is sequenced. When framing is open, duct routes and indoor locations are easier to coordinate with the architect and GC — we recommend an approach after reviewing the home and plans.
Yes. Remodel and custom-home scopes are a core fit. We coordinate mechanical design, rough-in, equipment placement, routing, and startup with the existing team.
Yes, where the project requires them. Load calculations are part of how we size ducted and ductless systems we install — not a standalone report-for-hire shortcut.
Sometimes. We measure leakage, sizing, returns, and room airflow before recommending reuse, modification, or replacement. Reusing poor ducts often leaves comfort problems equipment alone cannot fix.
Recent 3rdGen projects range from roughly $20,000 for ducted work with usable existing ducts to $40,000–$80,000 or more for complex whole-home, multi-zone, or remodel-coordinated scopes. Duct condition, zoning, access, routing, sound constraints, ventilation, and electrical coordination all move the number.
MCE, Bay Area, state, and federal incentives change over time and depend on equipment, utility account, and eligibility. Current programs may apply to your project — see /residential/rebates/ for an overview. We help identify programs and provide documentation where required; we do not guarantee a specific rebate amount.
Project Inquiry
Thanks — your project details are on their way to 3rdGen. We’ll review them and follow up about the next step.
