The Clean Air Chronicles

The Ryan's House

Pollard family, Monitoring,

The Pollards' House

Andrew speaking in his home

Andrew's House

reading Radon monitor,

Brian and Irene's House

Chris laughing in the basement

Chris' House

Ryan working in the basement

Ryan's House

Watch Ryan's Story

As Ryan found out, opening your windows isn’t always the best way to bring fresh air into the house. After participating in the ROCIS Low Cost Monitoring Project, Ryan Coon decided to retrofit the air handling system in his home to allow for continuous filtration.

Take a deeper dive into the data from Ryan’s air handler intervention below.

Intervention Summary


  • Furnace filter and return were very restricted

  • TESP very high (145 Pa) across filter alone


  • New, larger return air drop created to accommodate larger, deeper filter

  • Replaced PSC motor with an ECM for higher efficiency and more airflow options

  • TESP: 145 Pa to 51 Pa

  • Watt-draw: 445 W to 120 W → 325 W reduction!

  • Better 2nd-floor comfort and lower CO₂ levels in the bedroom while sleeping

Two men working on an HVAC system in basement

We helped Ryan retrofit his air handler to include an ECM blower, allowing for lower airflow and energy costs when running continuously. We also modified the return system to reduce airflow restrictions and accommodate the larger and deeper 20” x 25” MERV 13 filter. Ryan saw a noticeable reduction of CO₂ in the bedroom as well as dramatic reductions in particle counts on both indoor Dylos monitors, as seen in the chart below.

Dylos Data from Ryans House
Pre and Post Particle Data - Ryans house

Labor & materials cost: $1,000

Annual air handler fan cost for 24/7 operation: $131.40

Two men lifting air handler
Ryan with filter
Air handler intervention,

Air Handler Checklist

Is your house ready for an air handler intervention? Need some guidance to help figure it out? Ask your HVAC contractor to use the checklist on this page to assess your system.

Air Handler Inquiry

We lay out the whole process for assessing your air handler system for a retrofit on this page. It’s a great place to get started.



Air Handler Diagram

See how the intervention works.



Particle Filtration With Central Air Handlers: Folly or Opportunity

This presentation by ROCIS team members Linda Wigington and Rhett Major delves into the details of the air handler intervention.

Air Handlers With High-Performance Filters: A Closer Look

This ROCIS video explains the details of our approach to using high-MERV filters in central, continuous air filtration, including system modification, thermostats, and more.