Residential HVAC · San Rafael, CA
From post-war tract homes in Terra Linda to older houses near downtown, San Rafael has every kind of heating system. We replace failing furnaces and ACs with properly sized heat pumps, starting with a Manual J of your actual house.
Remodels · Retrofits · Heat Pumps · Multi-Zone Systems
Project Inquiry
Thanks — your project details are on their way to 3rdGen. We’ll review them and follow up about the next step.
Project fit
San Rafael has mixed housing, so no two jobs look the same. These are the projects we are called for most.
Full swap
One ducted heat pump replacing separate gas heat and cooling, with the duct work checked, sealed and corrected first.
Replacement & conversionSlab homes
For houses with ducts buried in concrete, new overhead ducts or ductless heads that skip the slab.
Heat pump installationSlopes
Equipment sized and staged for stairs, retaining walls and limited yards.
Ducted and ductless optionsSmall units
Separate, individually controlled systems for backyard units and multi-unit buildings.
ADU heating & coolingCalculations
Documented loads, equipment selection and duct design for the system we install, ready for the permit.
Manual J load calculationsAir quality
Higher-grade filters and enough return area for smoky wildfire weeks.
Ventilation & IAQExample of our field work
High-end residential remodel
A published Berkeley remodel showing how we plan zones, routing and permits for an older home, the same steps we apply to San Rafael houses.
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 example from a Berkeley, CA remodel, not a project in this city. Photos and full details on the project page.
View projectLocal projects
Recent installs by the 3rdGen crew that serves San Rafael: ducted and ductless heat pumps, air handlers and ductwork.
Many housing types, one method
A Terra Linda ranch on a slab, a hillside house reached by stairs and a flat-lot older home with a crawlspace all need different layouts. We calculate the load first and let the structure choose between ducted, ductless and hybrid.
The design summer day is about 87°F, hotter than coastal Marin, so cooling is a real part of the load here. Heat pumps do both jobs and avoid keeping a gas furnace and a separate AC alive.
The City’s housing data shows most San Rafael homes are older, so existing ducts, wiring and insulation are usually worth testing before they are reused.
Ducts in concrete or tight attics shape the choice between new overhead runs and ductless heads.
West-facing rooms and thin ceiling insulation can drive loads. We often recommend insulation fixes alongside the heat pump.
Each dwelling needs its own load and independent controls.
Filter sizing and return area are planned so better filters do not hurt airflow.
HVAC design in San Rafael
A 1950s ranch house in Terra Linda, a hillside home near Dominican and a duplex in the Canal area share almost nothing mechanically. We start each San Rafael job with a Manual J of that specific building and then choose between ducted, ductless and hybrid layouts.
San Rafael design conditions are roughly 37°F heating and 87°F cooling. Hamilton, a nearby station, runs colder and cooler (32°F and 84°F). The 87°F summer number is notably higher than Marin’s foggy coast, so cooling matters here and a heat pump gets real use in both seasons.
ACCA Manual J design data · San Rafael (ACCA micro-climate)
Terra Linda and Marinwood have a lot of single-story post-war tract homes, including Eichlers. Slab floors with ducts in the slab or in a low attic are common, and that decides the duct strategy early.
Older neighborhoods closer to downtown, like Gerstle Park and Dominican, have 1920s and earlier houses with raised floors, plaster walls and sometimes no ducts at all. Hillside houses add stairs and limited outdoor space.
Multi-unit buildings and ADUs are common too. Each separate dwelling needs its own load calculation and a clear path for refrigerant lines or ducts.
Eichler-style and slab-on-grade houses often have old ducts embedded in concrete. We evaluate whether to abandon them for new attic or overhead ducts, or to switch to ductless heads that avoid the slab altogether.
With an 87°F cooling design day, west-facing rooms and uninsulated ceilings can carry large loads. Manual J shows where added attic insulation or shading will cut the tonnage you need.
Replacements often come in a ton or more smaller than the old AC once the house is air-sealed and insulated. We select by calculated load, not by the nameplate on the unit we pull out.
Hill-adjacent neighborhoods can see wildfire smoke in bad seasons. We design for higher-MERV filtration with enough return area so filters do not choke airflow, and discuss ventilation controls during smoky weeks.
Where ducts run in a hot attic, we size and insulate them to hold temperature and keep static pressure within the air handler’s limits.
One ducted heat pump system replacing separate gas heat and AC, with duct and electrical scope included.
Replacement & conversion →Wall or ceiling indoor units connected by small line sets, a clean option when the old slab ducts are done.
Heat pump installation →A Manual J and S package behind the system we install, ready for the permit.
Manual J load calculations →Right-sized mini-splits for backyard units, with compliance paperwork and independent controls.
ADU heating & cooling →Better filters, ERV or HRV options and exhaust fixes that fit the system we design.
Ventilation & IAQ →Where incentive and financing programs apply to your project, we point you to them and keep the paperwork straight.
Financing options →Heat pump work is permitted through the City of San Rafael Building Division, part of Community Development. We provide the load calculation, equipment data and outdoor unit location the plan check needs. Unincorporated areas around the city, such as Marinwood and Santa Venetia, are handled by the County of Marin instead.
City homes take generation service from MCE, with PG&E delivering power. Rebates from TECH Clean California, BayREN, MCE and PG&E programs change, so we check current availability before quoting. Our rebates page covers how the programs generally work.
Terra Linda, Gerstle Park, Dominican, Loch Lomond, Peacock Gap and downtown, plus neighboring Larkspur, San Anselmo, Novato and Fairfax.
Homeowner reviews
207 Google reviews
Expand
Mitsubishi mini-split installed with outstanding care. Indoor and outdoor units done right. High efficiency meant a meaningful federal tax credit too.
Expand
Devin and his crew did a fantastic job installing AC for our whole house. High quality Mitsubishi equipment and a clean installation throughout.
Expand
Devin is meticulous, methodical, and knowledgeable. Professional crew and a heat pump install we trust completely.
Photos from the installs above
Read all 207 reviewsThe work, in order
Most San Rafael replacements fail on distribution, not equipment. The sequence below puts duct and load work ahead of the purchase.
Age, foundation type, current equipment, comfort complaints and your plans for the next ten years.
Heating and cooling loads for each room using the actual windows, insulation and leakage.
Equipment matched to the load, with duct sizes and registers designed to deliver the right airflow.
Building Division permit package with load report, equipment data and outdoor unit location.
Old equipment out, new system set, ducts repaired or replaced, electrical added.
Static pressure, airflow and refrigerant charge tested and recorded, then inspection and handoff.
What the job includes
Replacing aging heat and AC is rarely one swap. Ducts, drains, panel and gas all need a plan, so we handle them as a single project.
Before you sign off we measure airflow, confirm charge and set thermostat schedules with you.
Tell us about the projectFurnace and AC removed, gas shut off and capped as required.
Existing ducts tested and sealed, or replaced where the design calls for it.
Service capacity confirmed and dedicated circuits added under permit.
Static pressure, airflow and charge checked and recorded.
Cost
A straight furnace-and-AC swap on a house with good ducts costs far less than a slab home that needs new overhead runs. Duct condition, zone count, electrical work, access, and whether you add insulation or an ADU system are the main variables.
Prices as of November 2026. Complex whole-home and design-build projects can exceed these ranges. Rebates and incentives may reduce your net project cost.
Project inquiry
Tell us the neighborhood, house age, existing equipment and what is not working. A photo of the furnace and thermostat helps.
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
When a remodel or addition is under way, load changes and duct routes need to be settled with the framer and architect, not after drywall. We join the team at that stage.
We work within existing project teams in San Rafael 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
San Rafael questions, from slab ducts to smoke to permits.
Sometimes, but they are often cracked, damp or undersized. We inspect and test them before deciding. If they are not reliable, new overhead ducts or ductless heads avoid the slab entirely.
Yes. San Rafael’s design cooling temperature is about 87°F, and a properly sized heat pump handles that. The key is sizing to a Manual J rather than the old AC’s nameplate.
ACCA lists a design low around 37°F, with nearby Hamilton closer to 32°F. Cold-climate heat pumps keep full output in that range, so we do not usually need electric backup.
Yes. Mechanical work goes through the City’s Building Division. We prepare the load report and equipment documentation. Some outlying neighborhoods, like Marinwood and Santa Venetia, are in unincorporated Marin and use the County.
MCE provides generation to San Rafael by default and PG&E delivers it. Incentives from TECH Clean California, BayREN, MCE and PG&E change often, so we confirm what is open when we quote.
Yes. We size a small heat pump to the ADU’s own load, give it a separate thermostat and supply the documentation the permit needs.
We can design for higher-MERV filtration and larger return area so airflow stays healthy with the better filter. Ventilation controls help during smoky days.
Not always. We calculate panel load for the heat pump and any other electrification you plan, then decide whether a service upgrade or load management is cheaper.
Nearby service areas
Project Inquiry
Thanks — your project details are on their way to 3rdGen. We’ll review them and follow up about the next step.
