The EPA consistently finds that indoor air is 2–5 times more polluted than outdoor air. In Sacramento — where wildfire smoke season has extended, Central Valley pollen is intense, and homes are sealed tight against summer heat — indoor air quality has become an important health issue. Here's how to address it.
Start with Your HVAC Filter
The most impactful single change you can make is upgrading your air filter. Standard 1-inch fiberglass filters (the cheap blue or white ones) stop large particles but do almost nothing against the fine particles, pollen, and smoke that affect your health.
What to upgrade to:
- MERV 8: Significant improvement over fiberglass. Captures pollen, dust mites, and larger particles.
- MERV 11: Good all-around option. Captures most allergens and some fine particles.
- MERV 13: Captures fine particles including wildfire smoke PM2.5, bacteria, and most allergens. This is what hospitals use. For most Sacramento homes, this is the sweet spot.
Important: Higher MERV = more airflow restriction. Standard 1-inch filter slots don't work well with MERV 13 — they restrict airflow too much. A media cabinet filter with a 4–5 inch thick filter achieves MERV 13 efficiency without the airflow penalty. We install these frequently.
Wildfire Smoke: Sacramento's Specific Challenge
Wildfire smoke contains fine particles (PM2.5) at concentrations that can exceed 200 µg/m³ during major events — the "very unhealthy" range. Even with windows closed, indoor concentrations rise during smoke events.
For smoke events:
- Switch to recirculate mode on your HVAC system — this prevents outdoor air from being drawn in
- MERV 13 filtration significantly reduces smoke particle infiltration
- Portable HEPA air purifier in bedrooms provides additional protection during the highest-risk hours (especially overnight when smoke often settles)
- Seal gaps around doors and windows if you don't have a tight building envelope
Whole-home solution: A MERV 13 media cabinet filter combined with an ionization air purifier provides the best continuous protection against wildfire smoke.
Controlling Allergens
Sacramento's Central Valley location means intense pollen from almonds, grasses, oaks, and other plants. For allergy sufferers:
- MERV 13 filtration captures the majority of airborne pollen
- HVAC system runtime: Run your system's fan continuously (not just when heating/cooling) during peak pollen season to continuously filter indoor air
- UV air purifiers address mold spores, which are separate from pollen but also a common allergen
- Regular filter changes: During peak allergy season, check and replace filters more frequently
Controlling Mold
Mold in HVAC systems is a primary source of indoor mold spores. The evaporator coil and drain pan are consistently moist — ideal mold growth conditions.
Signs of mold in your HVAC:
- Musty odor when the AC or fan runs
- Visible mold around supply registers
- Family members with unexplained respiratory symptoms that improve when away from home
Solution:
- Annual evaporator coil cleaning removes biofilm buildup
- UV air purifier at the evaporator coil prevents mold from establishing. These are very effective — UV-C light at the right intensity kills 99%+ of mold spores and bacteria that pass through.
- Keeping humidity below 55% prevents mold growth throughout the home
Humidity: The Often-Overlooked Factor
Sacramento has extreme dry air in summer (outdoor RH below 20% during heat waves) but can have elevated indoor humidity in winter and spring. Both extremes affect air quality:
Too dry (below 30% RH): Dries respiratory passages, making you more susceptible to airborne pathogens. Also causes static electricity and wood damage.
Too humid (above 60% RH): Encourages mold growth and dust mite reproduction — both major allergen sources.
Solution: A whole-home humidifier (for dry winters) or dehumidifier (for humid periods) maintains the 35–50% ideal range.
The Ventilation Factor
Modern, tightly sealed homes have reduced natural air exchange — which saves energy but concentrates indoor pollutants. If your home is very tightly sealed, consider:
- Energy Recovery Ventilator (ERV): Brings controlled fresh air in while transferring heat/energy to the outgoing stale air. Ventilates without the energy penalty.
- Scheduled HVAC fan operation: Running the fan 20 minutes per hour, even when not heating or cooling, circulates and filters air more frequently.
A Simple Priority Order
- Upgrade to MERV 13 media cabinet filter (biggest single impact)
- Have HVAC system and evaporator coil cleaned
- Install UV air purifier at evaporator coil
- Add portable HEPA purifiers in bedrooms for smoke events
- Address humidity control if needed
- Consider ERV if home is very tightly sealed
Want to improve your home's air quality? Call PULSE HVAC at (916) 850-2221. We'll assess your current filtration and recommend a plan that fits your priorities and budget.