The HEPA Myth
Why High‑Flow MERV‑13 Wins in Real Rooms
HEPA ISN'T KING
In a real room, air swirls, recirculates, and mixes. A portable purifier with a high‑flow MERV‑13 filter can push more clean air every minute than a sluggish HEPA unit. That higher clean‑air delivery rate (CADR) knocks down particle levels faster, even though each individual pass is lower efficiency.
Why Multi‑Pass Matters
- Multi‑Pass Physics → Rapid Knock‑Down
At 5–10 air changes per hour, the same air recirculates and hits your filter again and again. Even removing just 50% of what’s left each pass through the filter quickly converges toward 99 % overall removal of the particles in the room. (ashrae.org) - Higher CADR → Faster Results
CADR = efficiency × airflow. MERV‑13 boxes routinely blow 300–400 cfm; many budget HEPA towers top out at 120–150 cfm. The result: up to 3× more clean air reaching your lungs every minute. (energyvanguard.com, energy.ucdavis.edu)
BREATHE EASY, LIVE BOLD
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HEPA vs. High‑Flow MERV‑13: Real‑World Race
Scenario: 250 ft² bedroom, target 5 air changes/hour.
| System | Airflow (cfm) | Single‑Pass Efficiency (PM2.5) | CADR (cfm) | Time to 90 % particle reduction |
| Compact HEPA tower | 120 | 99.97 % | 120 | ~29 min |
| Corsi‑Rosenthal Box (4× MERV‑13) | 350 | 75 % | 262 | ~13 min |
(Data: UC Davis WCEC case study.) (energy.ucdavis.edu)
MERV-13 OUTPERFORMS HEPA
CAPTURE
Traps 90 % of ≥ 0.3 µm particles.
FILTER
Removes mold spores & bacteria.
SAVINGS
Maintains airflow, cuts energy use.
DURABLE
Resists clogging for longer life.
MERV‑13: The Portable Powerhouse
| Advantage | What It Means |
|---|---|
| Captures the bad stuff | ≥ 90 % of ≥ 0.3 µm particles—pollen, mold, bacteria. (cleansehive.com) |
| Keeps the air moving | Low pressure‑drop keeps the fan humming, slicing energy use. (pickhvac.com) |
| Hospital‑grade Standard | ASHRAE Epidemic Task Force sets MERV‑13 as the baseline for infection control. (ashrae.org) |
| Long filter life | Huge surface area resists clogging—up to a year between swaps. (energy.ucdavis.edu) |
Backed by Standards & Science
- ASHRAE 62.1 & Epidemic Task Force: Upgrade to MERV‑13 (or higher) wherever possible. (ashrae.org)
- CDC: Upgrade central HVAC filter efficiency to a Minimum Efficiency Reporting Value MERV-13 or better. (archive.cdc.gov)
- US EPA: Filters with MERV-13 or higher ratings can trap smaller particles, including viruses. (US EPA)
- California DPH: MERV-13 or greater filtration is efficient at capturing airborne viruses and should be the target minimum level of filtration.(cdph.ca.gov)
- NIOSH: Increasing the MERV-13 filter thickness resulted in significantly lower aerosol exposures. (blogs.cdc.gov)
GIve back
Clean air shouldn’t be a privilege.
Here’s the thing that keeps us up at night – while some can afford $800 air purifiers, kids in underfunded schools are breathing whatever air happens to be there. That’s not okay with us. So for every batch of VELLOs we sell, we’re donating units to schools and communities that need them most. Your purchase doesn’t just clean your air – it helps clean the air for kids who deserve better.
- Certain percentage of sales will be donated to schools in need.
- We’ll show you exactly where your impact goes (full transparency)
- Partnering with education nonprofits who know which schools need help most
- Building healthier learning environments for all kids, not just the lucky ones