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AC installation for older Los Angeles homes
Older Los Angeles houses usually add three costs a newer one does not: ducts (published at $3,500–$8,000 new), a panel upgrade ($2,000–$7,500) and sometimes asbestos abatement on old duct wrap. A ductless mini-split often avoids the first.
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At a glance
What your heating system tells you
| What heats the house now | Ducts? | Usual cooling path |
|---|---|---|
| Floor furnace (grille in the floor) | None | Multi-zone mini-split, or new ducts plus central air or a heat pump |
| Wall heaters in individual rooms | None | Mini-split heads in the rooms that need cooling |
| Forced-air furnace with registers | Yes, sized for heat | Central AC or ducted heat pump if the ducts are large and sound enough |
| Radiators or a boiler | None | Mini-splits or a high-velocity system |
What an older house adds to an AC job
- No ducts, or heat-only ducts. Floor furnaces, wall heaters and small furnace ducts are common in prewar and midcentury LA housing. Cooling needs more airflow than heating.
- Panel capacity. A 100-amp panel may not take a new 240-volt cooling circuit without an upgrade.
- Asbestos. Old duct wrap can contain it; abatement is a separate licensed trade.
- Plaster and lath. Running new ducts or line sets through plaster walls costs more and takes longer than drywall.
- Attic and crawlspace access. Low or absent attics limit where ducts and an air handler can go.
The three ways to cool an older house
Multi-zone mini-split. Heads in the rooms that need them, line sets on the outside wall, no ducts. Least disruption to plaster; visible indoor heads.
Central air or a heat pump on new ducts. One system, hidden equipment, one thermostat. Needs attic or crawlspace room and the most construction.
Small-duct high-velocity systems run narrow flexible tubes through walls and ceilings. None of the LA price sources on this site prints a figure for them, so ask a contractor who installs them to quote.
What your house says about ducted or ductless
- Existing furnace ducts. If a forced-air furnace already has ducts, they may carry cooling if they are large and sound enough, which tips the answer toward central air.
- Attic height and ceilings. A low attic or plaster ceilings make new duct runs slow and costly, which favors a mini-split.
- Rooms you use. Cooling two bedrooms and a living room is a 2–3 zone mini-split. Cooling every room evenly favors ducts.
- Wall space and looks. Wall-mounted heads are visible. Ducted mini-split air handlers and ceiling cassettes hide more but cost more.
Adding central air to a house with no ducts
True central air needs ducts, so a house with wall or floor heaters gets a full duct system as well as the equipment. The work runs in this order:
- Load calculation and duct design: room-by-room airflow, then duct sizes and routes (what a Manual J measures).
- Air handler location: attic, closet, garage or crawlspace.
- Supply and return runs to each room, then cutting and patching the register openings.
- Electrical: circuits for the outdoor unit and air handler, sometimes a panel upgrade.
- Testing: more than 25 feet of new duct brings a whole-system leakage test under Title 24, so this job carries more testing than a mini-split.
It takes longer than a change-out because of the design, cutting and patching. Ask for the schedule in writing.
Published costs that apply to older houses
| Central AC, 3 tons, on usable ducts Reliable H&A, Cold Cloud | $8,000–$16,000 |
| Mini-split, 3 zones E & A Mechanical | $12,000–$16,500 |
| New or fully replaced ductwork Reliable H&A, Cold Cloud, HVACProjectCost | +$3,500–$8,000 |
| Panel upgrade Reliable H&A, Cold Cloud, E & A Mechanical, HVACProjectCost | +$2,000–$7,500 |
| Asbestos abatement Reliable H&A; least settled | +$2,000–$9,000 |
| Full system with all-new ducts HVACProjectCost | $14,000–$22,000 |
Published LA ranges, not our prices. All sources: cost guide.
The rebate math for an older house
In LADWP territory the rebate favors the path that avoids ducts. A ductless heat pump earns more per ton than a ducted one at every tier.
Ducted (central, split, packaged)
| Rated above | Per ton |
|---|---|
| 15.2 SEER2 and 7.7 HSPF2 | $1,000 |
| 16 SEER2 and 8 HSPF2 | $1,050 |
| 16.9 SEER2 and 8.1 HSPF2 | $1,100 |
| 17.8 SEER2 and 8.1 HSPF2 | $1,150 |
| 18.7 SEER2 and 8.5 HSPF2 | $1,200 |
| 19.6 SEER2 and 8.9 HSPF2 | $1,250 |
Ductless (mini-split, multi-split)
| Rated above | Per ton |
|---|---|
| 15.2 SEER2 and 7.8 HSPF2 | $1,500 |
| 16 SEER2 and 8.1 HSPF2 | $1,650 |
| 16.9 SEER2 and 8.3 HSPF2 | $1,800 |
| 17.8 SEER2 and 8.5 HSPF2 | $1,950 |
| 18.7 SEER2 and 8.7 HSPF2 | $2,100 |
| 19.6 SEER2 and 8.9 HSPF2 | $2,250 |
| 20.5 SEER2 and 9.1 HSPF2 | $2,500 |
LADWP customers only. Read on LADWP's Consumer Rebate Program page on 2026-10-20; tiers change, so check before you sign. Central, split, packaged, mini-split and multi-split heat pumps rated at least 15.2 SEER2 and 7.7 HSPF2. Packaged terminal heat pumps (PTHP) are not eligible. New construction and accessory dwelling units (ADUs) are not eligible. Apply after the equipment is bought and installed; the application must be postmarked within 12 months of the purchase date. The final approved Building and Safety permit is required.
Ways the total can come down
- A multi-zone mini-split instead of new ducts: $9,000–$12,500 for two zones.
- Reusing furnace ducts after sealing, if they are large enough: duct repair is published at $800–$4,500.
- A heat pump instead of AC if the furnace is due anyway, which may qualify for a utility rebate (heat pump rebates).
What to ask for an older house
- Have you inspected the attic or crawlspace, and where would ducts run?
- What is the panel's rating, and is an upgrade included?
- Have the old ducts been checked for asbestos?
- How will plaster be patched where lines pass through?
- Is the system a heat pump, and which LADWP tier does it reach?
- Which Title 24 tests apply, and who pays if old ducts fail? See the permit guide.
Put two quotes side by side in the quote tool.
Older panels and a heat pump: panel upgrades in LADWP territory.
Sources
- Reliable Heating and Air (Woodland Hills), AC installation cost in LA and Ventura County (retrieved 2026-09-29)
- HVACProjectCost.com, Los Angeles HVAC replacement cost (retrieved 2026-09-29)
- E & A Mechanical (Tujunga), heat pump installation cost in Los Angeles (retrieved 2026-09-29)
- Energy Code Ace (CEC-supported), Single-Family Compliance Manual ch. 9, § 150.2(b)1E–F, 2022 code text; confirm against the 2025 code in force since 1 January 2026 (retrieved 2026-09-29) — verify before relying on it
- Cold Cloud (Glendale), central air cost in Los Angeles (retrieved 2026-09-29)
- LADWP, "Consumer Rebate Program" (Heat Pump HVAC) (retrieved 2026-10-20)
- South Coast AQMD, "GO ZERO Incentive Program" (retrieved 2026-10-20)
Questions
What is the best AC for an old Los Angeles house without ducts?
There is no single answer. A multi-zone mini-split avoids ducts entirely and is published at $12,000–$16,500 for three zones. Central air with new ducts runs higher: $14,000–$22,000 for a full system with all-new ducts. Attic access and how many rooms need cooling decide it.
Do old ducts need to be tested when a new AC goes in?
Yes. Replacing or adding the outdoor unit, coil or air handler triggers Title 24 duct sealing and testing. Old ducts that leak must be sealed or replaced, which is why older houses carry the largest duct adders.
Can I keep my old floor furnace and add a mini-split?
Yes, many owners add mini-split heat pumps for cooling and keep the floor or wall furnace. Because most mini-splits also heat, the furnace can become backup. The AQMD GO ZERO rebate only pays when a gas furnace is replaced, so keeping it forgoes that rebate.
Which rebate is bigger for an older house: ducted or ductless?
On LADWP's page on 2026-10-18, ductless heat pumps earned $1,500–$2,500 per ton and ducted ones $1,000–$1,250 per ton. For a house with no ducts, the ductless route avoids the duct cost and earns the higher rebate tier.
Will a mini-split damage plaster walls?
Each head needs a small hole through an exterior wall for its line set and drain, which is far less cutting than new duct runs. Ask how the hole will be sealed and where the line-set cover will run outside.
What if the old ducts have asbestos?
Old duct wrap and tape in some older houses can contain asbestos. It must be handled by a licensed abatement contractor, not the HVAC crew. Reliable Heating and Air lists abatement at $2,000–$9,000. Ask for it to be quoted separately.
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