Radon Mitigation in MultiHousing by Focused Extraction

Radon often accumulates in "Radon Reservoirs" from which it may be extracted before it may be transported into a dwelling unit's Breathing Zone

How can I mitigate radon in a ground or upper floor apartment or condo?

1. If the radon level is less than 8 picoCuries per liter, the radon is likely coming from the building materials, especially concrete blocks in exterior walls. In such cases we recommend adding a carefully controlled quantity of filtered fresh air to dilute all indoor contaminants, including RADON, CO2, VOCs, PM2.5 and to pressurize the breathing zone to dry out and prevent mold in your home's exterior wall cavities. Fresh air is GOOD. Most homes do not have a fresh air supply, usually because builders have had bad experience with homes that develop mold problems when hot, humid fresh air is added. (We designed and build reliable automatic humidity controllers because they are still unavailable anywhere else)

We Designed and Manufacture the Daisy Deuce and the Daisy Ductless Modules, Filters, and Environmental Controllers here in Lee County, Florida.

Unpowered Fresh Air Duct

If your home has a ceiling stub in the air handler closet (left), we recommend the Plug 'N Play Daisy Deuce (right) to deliver a precisely correct, limited flow of MERV 13 filtered fresh air. High humidity and mold are prevented by our automatic humidity / performance controller with digital display. Radon level is easily adjusted.

Daisy Deuce with MERV 13 Filter

The Deuce fresh air filter (MERV 13 / blue band) meets new US EPA and ASHRAE recommendations. Particles are captured inside the filter for no-mess service. Filter exchange is quick and easy from indoors. Service life estimated at 12+ months. Available at https://smartairstore.com

2. If the radon level is above 8 picoCuries per liter, radon is probably  also entering from the soil under the slab. In such case, radon is entering through a "Radon Fountain" or a poorly sealed floor/slab penetration of pipe or electrical service. Unless such radon entry is sealed or blocked, excessive fresh air may be required to achieve radon reduction success. Excess fresh air is a serious NO-NO.

A leaky refrigerant chase. Sometimes these chases fill with water resulting in thermal electrolysis eating holes in the copper freon lines (Insulated in black foam sleeves in exposed space).

Leaky Penetrations. These days, most Builders take care when pouring a floor slab to ensure that penetrations are well sealed to block radon entry. However, even very small openings can allow radon to enter. Air handlers create powerful suction to "mine" or "pull" radon soil gas through even very small openings.

A Radon Fountain That Was Never Sealed

A Slab Penetration Allowing Soil Gas Rich With Radon To Enter Into a Breathing Zone. As you can imagine, this home had a serious radon problem from this concealed defect that was difficult to locate and to seal.

If there is No Ceiling Stub in the Air Handler Closet, click to go to the Daisy Ductless Page

For Multihousing With Builder-Installed Ceiling Stub:

The Daisy Deuce Fresh Air Delivery / Filtration Module

Installs in Air Handler Closets, but Delivers Fresh Air

into Large Room or Hallway for Unnoticeable Dilution, Tempering and Breathing Zone Pressurization

Fresh Air Delivery Stub 4" or 6" duct installed by HVAC firm

MERV 13 Filter Service from indoors

Installed for Functionality Testing (not yet wired)

QUESTION:  how much filtered fresh air is required to mitigate radon?

In most cases, Daisy Deuce airflow may limited to only 15 to 23 cfm of filtered fresh air in tight, energy efficient dwellings.

Such flows are nearly undetectable even right at the through-wall air delivery grille.

The Deuce Includes These Five Must-Have Features:

1. Long Life, High Performance Filtration, Easy Service

  • MERV 13 Filtration Performance nearly equivalent to an N-95 mask
  • 12+ month Service Life
  • Easy Service From Indoors
  • Always Available https://smartairstore.com

Factory Manufactured MERV 13, Meets new EPA and ASHRAE recommendations


  • A programmable Automatic Indoor Relative Humidity Controller to suspend fresh air delivery if indoor relative humidity rises above 59.9%
  • A Proven Record of Mold Prevention Reliability 
  • Humidity Control without the need to install a Dehumidifier later
  • The ability to reprogram the controller for a lower humidity limit if desired (requires technician)
  • Concealed Power Supply Optional

Plug-in Power Supply, Concealed Power Supply Availablel

3. A Simple Radon Level Adjustment

  • A Tamper Resistant, Simple, Accurate Radon Level Adjustment by jeweler's screwdriver
  • A Real-Time Digital System Performance Meter for precise adjustment.
  • A Totally Concealed Power Supply is also available


4. A Reliable and Accurate Digital Radon Meter with Audible Alarm

  • Records both short and long term radon measurements
  • Self-Calibrating
  • Audible alarm of radon mitigation system failure
  • No batteries to go dead, corrode and damage the instrument
  • Excellent history of accuracy and reliability

Safety Siren PRO 4 Radon Meter

5. Plug 'N Play Installation/Design for Simple, Quick Repair

  • Installation requires only a  4.25" hole saw and screwdriver
  • Almost No construction work, drywall work, repaint or touch-up required
  • Efficient dust capture by cyclonic particle separator
  • Integral, intumescent fire protection feature is available
  • All parts available online

Without a Deuce, fresh air delivery through the ceiling stub is controlled only by the thermostat   (or a table lamp timer) which operates only when it calls for heating or cooling. Some builders install a damper that  opens to let hot, humid, unfiltered air into the return air plenum during air handler operation.

But look out! If the AC fan is running without cooling (no dehumidification), humidity can skyrocket. More than one $50,000.00 mold remediation job was called for when an AC fan was left in the manual run position for weeks. (Fresh air delivery without dehumidification) = big $ mold remediation trouble) A Concealed Radon System Mold Nightmare

A thermostat is worse than a poor choice to manage radon levels and breathing zone pressurization. But it may do a good job of controlling temperature, which it is intended to do.

Fresh air needs a dedicated, automatic controller that will deliver the amount of fresh air needed to mitigate radon but not enough to create high humidity and mold. System control by a thermostat or table lamp timer is playing Russian Roulette that can create serious property destruction and occupant health risk from mold.

And everyone knows that in Hot, Humid Climates, Ugly Mold and Radon issues often result, requiring mold remediation, installation of a dehumidifier and radon mitigation upgrades.

Fresh Air Stub Inside the Air Handler Closet. A 6" X 4" Reducer quickly adapts the 6" stub to fit the Deuce to deliver adjustable radon mitigation and humidity control without a dehumidifier..

A Daisy Deuce Installed on a Fresh Air Stub. The Deuce Delivers Filtered Fresh Air through the wall and Into a Large Room or Hallway

The Blue Filter is a Quick Fit/Replacement into the Deuce Module from indoors in seconds.  MERV 13.  Available at https://smartairstore.com 

In MultiFamily Housing, Fresh Air Stubs conduct unfiltered fresh outdoor air into air handler closet in unknown and uncontrolled quantities. Sometimes a thermostat-controlled power-open damper is installed to deliver unfiltered fresh air into the return air plenum box. Experience confirms that humidity is out of control and may result in serious mold issues requiring mold remediation and installation of a dehumidifier.

A Daisy Deuce quickly attaches to the stub to draw air past an integral FireStop Belt and Filter. A 0-140 cfm ECM adjustable speed fan delivers the filtered air through-wall to a grille releasing the air outside the air handler closet. The air is quickly tempered as it mixes with conditioned indoor air. A Deuce Control Panel suspends air delivery if indoor relative humidity rises above 59.9% to prevent mold without dehumidifier installation.

The Deuce BLUE, cone-shaped air filter neatly captures particulate within itself and holds it for quick, convenient exchange without tools. Debris is captured inside the filter before the air reaches the fan. Filter service/exchange FROM INDOORS requires little or no cleaning. MERV 13 as recommended by USEPA.

Enter your text here...

Insert Image