Wildfire Smoke Indoor Air Quality Solutions for Louisville Homes

When the Front Range skies turn hazy, the air inside your home matters more than ever. You want a simple plan you can trust, not a maze of technical advice. This guide gives you clear steps to keep your Louisville home’s air cleaner during wildfire smoke, from easy same‑day fixes to smart upgrades that add comfort and value. You’ll learn how to set up a clean‑air room, choose the right filters, dial in your HVAC, and avoid common pitfalls. Let’s dive in.

Why wildfire smoke matters

Wildfire smoke carries tiny particles called PM2.5 that can get deep into your lungs. These particles drive most health concerns during smoke events. Children, older adults, pregnant people, and anyone with heart or lung conditions are more vulnerable. Pets can be affected too.

During fire season, check air quality often. You can track conditions with the AirNow real‑time AQI, and follow updates from Colorado and local public health agencies. For health guidance on smoke exposure, review the CDC wildfire smoke tips.

Build a clean‑air room

A clean‑air room is a single, closed space where you keep air as clear as possible during smoky periods.

Choose the right room

Pick a room you use most, like your primary bedroom or main living space. Favor interior rooms with minimal exterior walls and windows. Smaller rooms clean faster and stay cleaner with the same air cleaner. A room with one closeable door makes sealing easier.

Seal and prep fast

Close all windows and exterior doors. Seal gaps around the door with a towel or temporary weatherstripping. Use painter’s tape or window plastic on obvious leaks. Close fireplace dampers and cover unused exhausts or vents if possible.

Size your air cleaning

Aim for about 4 to 6 air changes per hour in the clean‑air room. Use Clean Air Delivery Rate (CADR) to size your portable air cleaner:

• Room volume = floor area × ceiling height
• Required CADR (cfm) = (room volume × desired ACH) ÷ 60
• Example: 200 sq ft × 8 ft = 1,600 cu ft. For 4 ACH → CADR ≈ 107 cfm. Choose a unit with a smoke CADR above that number.

Check the air cleaner’s smoke CADR on the product label or manual. If the room is large, two smaller units can outperform one oversized unit.

Place and run it

Set the air cleaner near the space you occupy, with the intake and outlet clear. Avoid blocking doors or cramming it in a corner. Run it continuously at a setting that achieves your target CADR. Expect more noise on high, but faster reductions in PM2.5.

Keep it comfortable

With windows closed, indoor humidity and heat can rise. Use your AC or a dehumidifier to stay comfortable and prevent moisture issues. Remember that portable HEPA cleaners do not cool or dehumidify, so coordinate with HVAC as needed.

Choose the right air cleaner

You have three practical paths: true HEPA portable units, higher‑efficiency in‑duct filters, and a tested DIY option known as the Corsi‑Rosenthal box.

True HEPA portable units

True HEPA traps at least 99.97% of particles at 0.3 microns, which targets PM2.5 from smoke. Choose a unit by matching the smoke CADR to your room size and desired air changes. Look for verified HEPA language, manageable filter costs, reasonable noise on higher speeds, and efficient operation. For consumer guidance, see ENERGY STAR recommendations for portable air cleaners.

Replace filters on schedule, and expect more frequent changes after heavy smoke days.

DIY Corsi‑Rosenthal box

This low‑cost option uses a modern box fan with a fused plug plus four MERV‑13 filters taped into a cube. A well‑built unit can provide strong clean‑air delivery for a modest price, though results vary by build quality.

Build and use it safely:

• Use a newer box fan with a fused plug and intact cord.
• Seal filters well so air goes through the filters, not around them.
• Ensure adequate airflow and do not block the fan.
• Place it securely and avoid leaving it unattended for long periods unless your fan is rated for continuous duty.

What to avoid

Skip ozone generators and air cleaners that produce ozone or use unverified ionization claims. These can irritate lungs and do not address smoke effectively. The EPA Guide to Air Cleaners in the Home explains which technologies work for particles like PM2.5 and which to avoid.

Use your HVAC wisely

Your furnace or air handler can help clean indoor air when used correctly.

Upgrade filters with care

MERV 13 filters capture a high fraction of PM2.5 and are commonly recommended for smoke mitigation in forced‑air systems. Many homes start with MERV 8 or lower. Higher MERV increases resistance to airflow, which can stress older systems or reduce performance.

Before upgrading, consult an HVAC professional. Options include a larger filter rack or a high‑efficiency media filter that keeps pressure drop manageable. Whole‑house HEPA is possible with the right equipment and pro installation.

Set the fan to circulate

During smoke events, set the fan to ON instead of AUTO so air moves through the filter continuously. This helps reduce indoor PM2.5 between outdoor smoke peaks. If your system brings in outdoor air through a fresh‑air intake, economizer, ERV, or HRV, set it to recirculation or turn off intake during heavy smoke. Check your equipment manual or call a pro if you are unsure.

Balance energy and comfort

Running the fan nonstop raises electricity use and noise. Higher‑MERV filters add resistance and can affect heating or cooling output on some equipment. During smoke, the health benefit typically outweighs these tradeoffs.

Fast action checklist

Use this punch‑list to protect your indoor air when smoke rolls in.

Immediate steps (30–60 minutes)

• Close windows and exterior doors; shut the fireplace damper.
• Choose and set up your clean‑air room; seal obvious leaks with towels and tape.
• Turn the HVAC fan to ON only if your system does not increase outdoor air intake when the fan runs. If you are unsure, rely on a portable HEPA in the clean‑air room.
• Turn off whole‑home ventilation or set ERV/HRV to recirculate if possible.
• Run a portable HEPA air cleaner sized for the room on a higher setting to start.
• Avoid particle‑generating activities: frying, candles, smoking, and vacuuming without a HEPA vacuum.

Same‑day tasks

• Check your HVAC filter and replace if dirty; if planning a temporary upgrade, have at least one MERV 13 filter on hand.
• If you have a window AC, keep windows closed and run it on recirculation mode if available. Most portable AC units recirculate indoor air.
• Stock your clean‑air room kit: N95 respirators, spare HEPA filters, tape, weatherstrip, snacks, and needed medications.

Before fire season

• Buy HEPA air cleaners sized for main living spaces and bedrooms.
• Stock replacement filters for both HEPA units and your HVAC.
• Consider building a Corsi‑Rosenthal box as a budget backup.
• Schedule an HVAC tune‑up and discuss a larger filter rack, a higher‑capacity blower, or a whole‑house filtration solution.

Longer‑term upgrades that add value

Some improvements deliver daily comfort and can appeal to future buyers in smoke‑prone regions.

Low to moderate cost

• Place high‑quality HEPA cleaners in bedrooms and living areas.
• Keep spare MERV 13 filters on hand for smoke season.
• Weatherstrip doors and windows to cut infiltration and save energy year‑round.

Professional upgrades

• Install a properly sized in‑duct MERV 13 or 14 filter with a larger rack to lower pressure drop.
• Add a dedicated whole‑house HEPA or high‑efficiency media filter with the right fan or blower upgrade.
• Use smart controls or indoor air quality sensors to automate fan operation and ventilation based on outdoor AQI.

Weigh the tradeoffs

Portable HEPA units are fast and flexible. Whole‑house solutions cost more but provide continuous, quiet protection across rooms. Running fans and higher‑MERV filters uses more electricity, but cleaner air during smoke events often justifies the cost.

Local alerts and resources

Set up a simple monitoring routine so you know when to act. Check the AirNow AQI map and guidance several times a day during active smoke. Follow health advisories from Colorado and Boulder County public health channels. For consumer background on filtration and which technologies work, consult the EPA air cleaner guide and the CDC’s wildfire smoke tips.

Staying prepared is the easiest way to protect your daily routine and peace of mind. With a clean‑air room ready, the right filters on hand, and a simple HVAC plan, you can keep your Louisville home a calm, clean refuge when the skies turn smoky.

If you are weighing which upgrades will best support your lifestyle or future sale, let’s talk about your goals and timeline. Elevate Your Real Estate Journey with Unknown Company.

FAQs

What is PM2.5 in wildfire smoke?

• PM2.5 refers to fine particles 2.5 microns and smaller that can travel deep into your lungs and drive most health impacts during smoke events.

How do I know when to close windows in Louisville?

• Check the AirNow AQI; when air quality is poor, keep windows closed, switch to recirculation, and run indoor filtration.

What size HEPA purifier do I need for a bedroom?

• Calculate required CADR: room area × ceiling height × desired ACH, then divide by 60; for 200 sq ft and 8 ft ceilings at 4 ACH, aim for at least 107 cfm smoke CADR.

Should I run my HVAC fan during smoke?

• Yes, if your system does not draw outdoor air when the fan runs; set the fan to ON to circulate through a higher‑MERV filter, or use a portable HEPA if unsure.

Are ozone or ionizer air cleaners good for smoke?

• No; avoid ozone‑producing devices, and rely on proven filtration like true HEPA and MERV 13 according to EPA guidance.

Is a Corsi‑Rosenthal box safe to use at home?

• Yes, if built with a modern box fan with a fused plug, sealed filters, stable placement, and reasonable run times; avoid leaving it unattended for long periods.