Central Air Installation in Los Angeles, CA Whole-Home Cooling Installed Cleanly

When whole-house ducted cooling is the right answer

Central air earns its keep when the house has a usable attic or crawlspace route, rooms that should behave alike, and an electrical service that can take the load. It struggles where ceilings are plaster, the attic pinches to nothing at the eaves, or a hillside floor plan stacks rooms in ways no trunk line can serve without soffits. The honest test is whether supply and return can both reach every room. A design that gets supply air into a bedroom and leaves no return path has built its own hot room.

A new duct system answers to a tighter figure

Where the ducts form an entirely new system, measured leakage must come in at or below 5 percent of system airflow. The code defines an entirely new system as at least 75 percent new duct material, with any reused parts accessible. Extend or partly replace an existing system with more than 25 feet of new duct instead, and the target becomes 10 percent total leakage or 7 percent to outside. A brand-new layout also has to satisfy filtration, static-pressure probe, airflow and fan efficacy requirements. Those numbers reward planned trunk-and-branch layouts over long flexible runs pulled around framing.

The attic package that rarely appears on a first bid

Put an air handler and ducts in a vented attic and a second set of rules arrives with them. The ceiling between conditioned rooms and the attic must be air sealed. The attic floor over conditioned space is insulated to R-49. Recessed can lights that are not rated for insulation contact have to be swapped for rated fixtures or covered with a fire-rated enclosure so insulation can pass over them. Attic ventilation has to meet residential code. In a 1920s bungalow in Highland Park or West Adams that is real carpentry and real electrical work, not an afterthought, and it belongs in writing before the crew arrives.

Insulation on the runs depends on your side of the hills

Duct insulation in unconditioned space is set by climate zone. Coastal parts of the city sit in zone 6, where R-6 is the minimum on new duct. Cross into the Valley and zone 9 requires R-8. That is not a preference an installer gets to trade away, and it interacts with attic temperatures: a run baking above a Sherman Oaks ceiling loses far more capacity than the same run in Echo Park. Design temperature moves with it, from 84 degrees at the airport station to 96 in Burbank, so the Valley house needs both the heavier insulation and more capacity behind it.

Sizing, oversizing and the airflow proof

Capacity limits apply unless airflow is field verified at 350 cubic feet per minute per ton or better. Federal guidance puts normal cooling airflow around 400 to 500 cubic feet per minute per ton, and warns that poor airflow can cost 5 percent or more of a system's potential. Oversizing is the common error: research on units oversized by half or more found roughly 9 percent higher annual cooling electricity and 13 percent higher summer peak demand, with short cycles that wear equipment and never dry the air. A correctly sized system with generous return area beats a larger one choked by a single undersized grille.

Filtration, smoke season and the return you actually need

Regional air quality guidance for smoke events recommends filters rated MERV13 or higher, closing any fresh-air intake so the system recirculates, keeping a clean spare filter on hand, and adding a portable HEPA cleaner for one room. It also advises against whole-house fans and evaporative coolers that pull outdoor air during smoke. Dense filter media only works if the return was designed for it, which is a design decision made during installation, not a filter you buy later. Say at the start that you want smoke-capable filtration so the return and filter rack get sized for it.

What the visit and the number look like

Expect measurement first: rooms, glass, attic clearance, joist depth, panel capacity, condensate route and outdoor unit placement. A serious proposal shows the duct layout, register and return locations, insulation values, the sealing and testing plan, the permit, the attic work and the rater visit. Cost tracks house size, register count, attic access and how much of the attic package the job triggers. A house needing new ducts, attic insulation and a service upgrade lands in a different range than a straightforward equipment change.