Rebuilding an Altadena Home’s HVAC After the Eaton Fire
The house survived the fire. The HVAC system didn’t come through clean. We replaced it from a blank page, and the work passed the inspection of a homeowner who spent his career as a building inspector.
Smoke- and ash-contaminated equipment and ductwork removed, a three-zone heat pump layout designed with Manual J and Manual D, all-new ductwork, an LA County permit, HERS verification and a passed final inspection.
- Location
- Altadena, CA 91001
- Project type
- Smoke-damaged HVAC replacement and full system redesign
- System
- Three heat pump zones on R-32, gas furnace retired
- Equipment
- Daikin Fit 4-ton heat pump, Daikin Aurora concealed ducted unit, Daikin Entra mini-split
- Design
- Manual J load calculation, Manual D duct design
- Ductwork
- All new, suspended, sealed and insulated
- Controls
- Daikin One smart controls with app access
- Permit and testing
- LA County permit (EPIC-LA), HERS verified, final inspection passed
From a smoke-damaged system to three clean zones
We could have swapped in the same equipment and hooked it up to new ducts. The old system had never worked well for this house, so we started over.
- 01
Smoke damage
Smoke and ash pulled through the return into the furnace cabinet, the liner and every flex duct.
- 02
The math
A room-by-room Manual J showed the house needed three independent zones, not one system.
- 03
Three zones
A Daikin Fit heat pump, a Daikin concealed ducted unit for the master suite and a Daikin Entra mini-split for the sunroom.
- 04
New ductwork
Every old duct out, the new system built to a Manual D design, permitted, tested and inspected.
Where it started
In January 2025 the Eaton Fire tore through Altadena. This house survived, but the HVAC system didn’t come through clean. Smoke and ash had been pulled through the return and spread through the whole system. There was soot in the furnace cabinet, on the internal liner of the old unit, and throughout the ductwork.
The ducts were flexible ducts with a porous inner layer. Once smoke and fine ash get into that material, no cleaning can make them safe to breathe through again. Running the old system would have kept pushing fire residue into every room of the house.
A house that never had the right system
The original setup was one 15-year-old gas furnace with an air conditioner, serving the whole house through a single duct system. The house isn’t simple. It’s architecturally complex, with a sunroom, a large living room, and a master suite on the second floor. The sunroom takes heavy solar gain. The living room is a big open volume. The master upstairs collects heat from the rest of the house. One thermostat in one spot can’t keep all three comfortable, and it never did. So the math came first.
- 01
Room by room
We did a room-by-room Manual J heat load calculation. It covered the glass in the sunroom, the orientation of every wall, ceiling heights, and the stack effect pushing heat upstairs.
- 02
Three zones, confirmed
The results confirmed what the owners already knew from living there: the house needed three independent zones, not one system pretending to be three.
- 03
Ducts sized to the rooms
We then did a Manual D duct design for the ducted zones, so every supply and return is sized for the airflow that room actually needs.
Three zones, three right-sized solutions
Each part of the house got the system that fits its load: a heat pump for the main living areas, its own ducted unit for the master suite and a ductless mini-split for the sunroom.
Daikin Fit heat pump, 4 ton
A slim, quiet, variable-speed system that heats and cools the main part of the house through brand-new ductwork.
Daikin Aurora concealed ducted unit
A single-zone, mid-static ducted unit hidden in the attic, with its own supply and its own return. The bedroom is no longer at the end of a long duct run shared with the rest of the house. It has its own system and its own thermostat.
Daikin Entra wall-mounted mini-split
A room with this much glass needs fast, independent control. A ductless unit handles the solar load directly, without oversizing the main system to compensate.
The gas furnace was retired completely, and all three zones now heat and cool with Daikin heat pumps on R-32 refrigerant. The ducted systems run on Daikin One smart controls with app access.
Every old duct came out
Every piece of the old smoke-contaminated ductwork was removed and hauled away. The new duct system was built to the Manual D design. In the attic, every run is suspended off the attic floor on proper supports, pulled straight and tight with no sags, kinks or excess length. All connections are sealed and insulated to code.
Straight, tight, properly supported ducts aren’t just about looks. They move more air with less fan energy, run quieter, and pass HERS duct-leakage testing. That is the standard for every ductwork installation we do.
What Cold Cloud Mechanical completed
From tearing out the contaminated system to the county final inspection, the project was designed, installed and documented by our team.
- Removed the smoke- and ash-contaminated equipment and every piece of the old ductwork, and hauled it away.
- Ran a room-by-room Manual J load calculation and a Manual D duct design for the ducted zones.
- Laid out three zones: a 4-ton Daikin Fit heat pump for the main living areas, a single-zone Daikin Aurora concealed ducted unit (mid-static) for the master suite and a Daikin Entra wall-mounted mini-split for the sunroom, all on R-32 refrigerant.
- Retired the gas furnace completely. All three zones now heat and cool with heat pumps.
- Built all-new ductwork to the Manual D design, with every attic run suspended off the floor on proper supports, pulled straight and tight, sealed and insulated to code.
- Set up Daikin One smart controls with app access for the ducted systems.
- Pulled the LA County mechanical permit through EPIC-LA, completed the Title 24 energy documentation, had an independent HERS rater verify the system and passed the county final inspection.
Permits in unincorporated Altadena
Altadena is unincorporated, so permits go through Los Angeles County rather than a city. We pulled the LA County mechanical permit through EPIC-LA, completed the Title 24 energy documentation, had an independent HERS rater verify the system, and passed the county final inspection.
The inspection we didn’t know we were getting
The homeowner didn’t mention something until the last day of the project, when he walked through to accept the work: he had spent his entire career as a city building inspector. For decades his job was to look at other contractors’ work and find what was wrong with it.
He went up into the attic, looked at the ducts, and came back down. He said the ducts didn’t touch the floor anywhere, every run was straight and tight, and everything was done to code. After a lifetime of inspecting other people’s work, he hadn’t expected to see his own attic look like that.
It’s one of the best reviews we’ve ever received. It came from someone who knows exactly what good work looks like, because he spent his career seeing what bad work looks like.
The result
The home now has three independent comfort zones, all-new clean ductwork, quiet heat pump heating and cooling in place of the old furnace, and no trace of fire residue in the air system. For another wildfire rebuild in the same area, see our Daikin DH6 heat pump project in Altadena, or read about our HVAC services in Altadena.
- 01
Three independent zones
The main living areas, the master suite and the sunroom each heat and cool on their own, with quiet heat pumps in place of the old furnace.
- 02
Clean air system
All-new ductwork and no trace of fire residue in the air system.
- 03
Designed, permitted, approved
Real load calculations, a duct design, an LA County permit, an independent HERS rater, the county inspector, and a retired inspector who happens to live there.
Questions about HVAC after a wildfire
Can smoke-damaged HVAC ductwork be cleaned after a wildfire?
Rigid metal ducts can sometimes be cleaned. Flexible ducts have a porous inner layer that traps soot and ash, so they can’t be cleaned reliably and should be replaced. The furnace or air handler cabinet, the internal insulation liner and the coil should be inspected as well.
Do I need a permit to replace HVAC in Altadena?
Yes. Altadena is unincorporated, so the mechanical permit is issued by LA County (through EPIC-LA), not a city. Title 24 compliance, HERS verification and a final inspection are required.
What’s the best HVAC setup for a house with a sunroom?
Usually a separate zone. Sunrooms have much higher solar heat gain than the rest of the house. A dedicated ductless mini-split handles that load without oversizing the main system.
Why does duct installation quality matter?
Sagging, kinked or crushed flex ducts restrict airflow, waste energy, make noise, and often fail HERS duct-leakage testing. Properly supported, straight ducts deliver the airflow the system was designed for.
Rebuilding HVAC after fire or smoke damage?
We start with a room-by-room load calculation and a duct design, replace what can’t be made clean, and handle the permit, Title 24 documentation, HERS verification and final inspection.
Prefer to call? (747) 298-8580