Quick answer: The most effective way to protect indoor air quality from wildfire smoke in Los Angeles is a MERV 13 (or higher) filter in your existing HVAC system, paired with a dedicated fresh-air intake that can be sealed during smoke events. A filter upgrade costs $150–$400; a full smoke-ready HVAC retrofit runs $1,500–$5,000. APLA Construction (CA Lic #1136359) retrofits HVAC systems across Greater Los Angeles for wildfire smoke resilience.
Wildfire smoke events have become a recurring part of the Los Angeles calendar, and standard residential HVAC filtration isn’t built to handle the fine particulate matter (PM2.5) that smoke carries deep into a building. Unlike a standard AC tune-up, protecting indoor air during a smoke event is a specific, addressable HVAC scope — and one most LA homes haven’t been upgraded for.
Most residential HVAC systems ship with a MERV 8 filter, adequate for dust and pollen but largely ineffective against the ultra-fine PM2.5 particles in wildfire smoke. Upgrading to MERV 13 captures a significantly higher share of smoke particulate — the level generally recommended for wildfire-prone regions — without the airflow restriction that can strain a system not designed for it.
The single highest-value change. Requires confirming your existing system’s blower can handle the added static pressure — some older systems need a filter housing upgrade to accommodate a MERV 13 filter without restricting airflow.
Many HVAC systems draw some outside air continuously. A manually or automatically sealable damper lets you cut off outside air intake during active smoke events while still running the system on recirculated, filtered indoor air.
For bedrooms or rooms without strong HVAC coverage, a portable HEPA unit supplements whole-home filtration — not a replacement for HVAC-level filtration, but a useful addition for sleeping areas during multi-day smoke events. See the EPA’s official guidance on setting up a clean room for the specific setup that works best.
Smoke infiltrates through gaps around doors, windows, and attic access points as much as through HVAC. Basic weatherization — door sweeps, window seals — reduces the smoke load your filtration has to handle in the first place.
| Upgrade | Typical Cost |
| MERV 13 filter + housing check | $150–$400 |
| Sealable fresh-air damper | $500–$1,200 |
| Portable HEPA units (per room) | $200–$600 each |
| Full smoke-ready retrofit (filter + damper + basic sealing) | $1,500–$5,000 |
Homes in and near Very High Fire Hazard Severity Zones — Malibu, Pacific Palisades, Topanga, Altadena, and hillside neighborhoods throughout the city — see the most direct wildfire exposure, but smoke drift affects air quality across the entire LA basin during major fire events, including areas well outside the fire zones themselves. See our fire hazard severity zone guide for which neighborhoods carry the highest direct fire risk.
Not if it’s sized and installed correctly. Some older or smaller systems need a filter housing upgrade to accommodate MERV 13 without restricting airflow — we check your specific system’s blower capacity before recommending it.
Yes, generally — running the fan continuously on recirculate (not drawing outside air) with a MERV 13 filter actively cleans indoor air. Sealing the outside air intake during active smoke is the key step that makes this effective.
They’re effective for a single room but don’t cover a whole home the way upgraded HVAC filtration does. Most homes get the best results combining both — whole-home HVAC filtration plus portable units in bedrooms.
Every 60–90 days under normal conditions, more frequently during active fire season or after a major smoke event, since the filter is capturing significantly more particulate than a standard filter.
In most cases it can be added to your existing system. A full HVAC replacement isn’t required just for smoke readiness — we evaluate your current system first.
APLA Construction (CA Lic #1136359) assesses and retrofits HVAC systems for wildfire smoke resilience across Greater Los Angeles, including homes in and near Very High Fire Hazard Severity Zones.
Call: (818) 818-4419
Email: info@aplaconstruction.com
CA General Contractor License #1136359