Radon Machine in House: What Homeowners Need to Know
This guide summarizes EPA, CDC, and Colorado state guidance on radon mitigation current as of 2026; engage a certified radon mitigation contractor for any actual system design or installation decisions. The phrase “radon machine in house” is colloquial shorthand for the mitigation fan — the active component of a sub-slab depressurization system that pulls radon-laden air from under the foundation slab and exhausts it above the roofline. Common fan models include the RadonAway RP series, the Festa AMG series, and the Eagle Tech EZ series. Retail pricing runs $250-500 per fan. The fan is part of a larger system that includes a sealed slab penetration, perforated PVC piping, a manometer pressure gauge, and an outdoor exhaust point.
What the radon machine actually does
The mitigation fan creates negative pressure in the soil beneath the foundation slab. Radon gas migrates from soil into homes through cracks, slab penetrations, and porous foundation surfaces because soil gas is typically at slightly higher pressure than indoor air. The fan reverses that pressure differential by extracting air from beneath the slab and exhausting it outside, which prevents radon entry into the living space.
The fan runs continuously. Operating cost is modest — typical sub-slab depressurization fans draw 30-90 watts and add $40-100 per year to the home’s electrical bill. The fan is rated for continuous duty and typically lasts 10-20 years before requiring replacement. Manufacturers warrant the fans for 5 years against motor failure.
The “machine in the house” is misleading terminology in one sense: the fan itself is usually installed outside the conditioned envelope. Common installation locations are the attic (with the exhaust riser routed through the roof), the exterior of the home (in a weatherproof enclosure), or the garage (when the garage is unattached or has its own ventilation). The fan should not be installed in living-space areas because any leak in the suction-side piping would release radon-laden air into the home.
Common mitigation fan models
The RadonAway RP series is the most widely-installed mitigation fan family in the US. The RP145 (4-inch duct, 70-watt motor) is sized for typical single-family slab-on-grade or basement installations. The RP265 (4-inch duct, 90-watt motor) handles larger homes or more difficult soil conditions. The RP380 is the heavy-duty option for large homes or commercial applications.
The Festa AMG150 (formerly Fantech Rn1) is a quieter alternative often selected for homes where the fan’s audible noise was a concern. Festa fans run at lower RPM than the RadonAway equivalents and produce 5-10 dB less noise at the same airflow.
The Eagle Tech EZ200 and EZ280 are mid-priced alternatives that have gained market share among installers looking for a balance of cost and reliability. Other brands available in the Front Range market include AMG (American Mitigation Group, the manufacturer of the Festa line) and various private-label products sold through radon supply distributors.
Retail pricing for the most common fans runs $250-400 for the RadonAway RP145, $300-450 for the RP265, $350-500 for the Festa AMG150, and $250-350 for the Eagle Tech EZ200. Installation labor and other system components are not included in the fan price.
The complete sub-slab depressurization system
The fan is one component of a multi-part system. A typical sub-slab depressurization (SSD) installation includes a sealed slab penetration with a suction pit cleared below the slab, perforated PVC piping connecting the suction point to the fan, the mitigation fan itself, smooth-wall PVC piping from the fan to the outdoor exhaust point, a manometer (U-tube pressure gauge) confirming the system is creating negative pressure, an exhaust point above the roofline and away from windows and HVAC intakes, and a system label identifying the installation contractor and date.
The full system installation cost in the Front Range market runs $1,200-2,500 for typical single-family slab-on-grade or basement homes. Larger homes, multi-level homes with multiple foundation types, and homes requiring multiple suction points can exceed $3,000-4,500 for the installation.
For broader context on residential mitigation systems and their components, see our residential radon mitigation guide and our guide to how radon gas removal systems work.
How to know if the radon machine is working
The manometer pressure gauge is the operator’s primary indicator. A properly functioning SSD system shows a visible water-column pressure difference on the U-tube manometer — typically 0.5 to 2.0 inches of water column. The pressure difference indicates the fan is creating sub-slab suction.
If the manometer shows zero pressure difference, the fan has likely failed (most common cause), the suction-side piping has come loose or developed a leak, or the slab seal has degraded enough to break suction. Homeowners should check the manometer monthly and contact the original installer when readings change materially.
Post-mitigation radon testing should be performed within 30-60 days of installation to verify the system has reduced indoor radon below the EPA action level of 4.0 pCi/L. Front Range homeowners should retest every 2-3 years thereafter, since soil gas conditions and home pressure dynamics can change over time. The retest uses the same testing approaches available for initial radon screening.
Fan replacement when the machine fails
Mitigation fans typically last 10-20 years. Failure modes include motor seizure (gradual reduction in airflow followed by complete failure), bearing failure (audible noise change before complete failure), and capacitor failure (sudden stoppage with no warning). The first indication is usually the manometer showing reduced or zero pressure difference.
Replacement involves removing the failed fan and installing a new fan in the same location with the same duct configuration. Most installations can use a like-for-like replacement; same model, same brand. The labor for a straightforward fan swap runs $200-500 plus the cost of the new fan. Total replacement cost typically $500-900.
Property owners replacing a fan should verify the manometer reads correctly on the new installation. The replacement should restore the pressure differential to the original installation values. Significant deviation suggests the replacement fan is undersized for the home’s needs or that other system components have degraded.
What the radon machine cannot fix
Three situations limit what an SSD system can achieve. First, homes with crawlspaces under part of the foundation cannot be mitigated through sub-slab depressurization alone — the crawlspace requires sub-membrane depressurization or other mitigation approach. Two-system installations (SSD for the slab portion plus separate crawlspace mitigation) are common in homes with mixed foundation types.
Second, homes with elevated radon in well water carry a separate exposure pathway that the slab mitigation does not address. Well-water radon is typically mitigated with a granular activated carbon (GAC) treatment system installed at the water service entry. Combined air and water mitigation is necessary in homes with both elevated indoor air radon and elevated well-water radon.
Third, homes with very high soil radon concentrations sometimes require multiple suction points or larger fans to achieve adequate sub-slab depressurization across the full foundation footprint. The installer determines the appropriate configuration based on diagnostic testing (smoke-tube communication test, baseline radon measurements) before finalizing the system design.
The piping that connects to the radon machine
The fan only matters when paired with properly sized and routed piping. The suction-side piping (between the slab penetration and the fan) is typically 3-inch or 4-inch Schedule 40 PVC. Smaller piping creates flow restrictions that reduce the fan’s effective capacity; larger piping is harder to route through interior chase walls and adds material cost without proportional benefit.
The exhaust-side piping (between the fan and the outdoor exhaust point) is the same diameter as the suction piping. Routing should be as straight and short as practical to minimize flow restrictions. Long exhaust runs with multiple elbows reduce fan capacity and may require a larger fan than the diagnostic testing originally suggested.
The exhaust point must terminate at least 10 feet above grade, at least 10 feet from any operable window, and not under an overhang that could trap exhausted radon. Front Range installations commonly terminate the exhaust on the highest accessible roof point above the soffit line. Inadequate exhaust point placement is one of the most common installation defects identified during post-installation review by independent inspectors.
Noise considerations for the radon machine
Mitigation fans produce audible noise during continuous operation. RadonAway RP series fans typically produce 50-58 dB at 5 feet (similar to a bathroom exhaust fan); Festa fans produce 45-52 dB at 5 feet (noticeably quieter). The noise is usually not objectionable when the fan is installed outdoors, in an attic, or in an unfinished area, but becomes a concern when the fan is mounted on an exterior wall near a bedroom window or in any indoor space adjacent to living areas.
Homeowners bothered by fan noise have three options: relocate the fan to a less audible location, replace with a quieter Festa fan, or add vibration-dampening mounts and acoustic enclosure to reduce the noise transmission. Vibration dampening alone often reduces perceived noise by 3-6 dB. A quieter replacement fan plus dampening can reduce perceived noise by 10-15 dB.
The fan itself is not the only noise source. Air rushing through the PVC piping at the slab penetration sometimes creates a low whooshing sound that homeowners notice when listening for it. This is normal and indicates the system is moving the expected airflow.
Choosing the right fan for your home
The mitigation contractor selects the fan based on diagnostic testing of the home’s sub-slab pressure field. Homes with permeable sub-slab fill (gravel base under the slab) need less fan capacity than homes with tight clay or other low-permeability material. The diagnostic test reveals which fan size is appropriate.
Homeowners should not select the fan themselves on a new installation. The fan is one variable in a system designed by the installer based on home-specific conditions. Selecting too small a fan results in inadequate mitigation; selecting too large a fan wastes electricity and increases the risk of pulling conditioned air through cracks or other unintended pathways.
Replacement fans on existing systems should match or modestly upgrade the original fan capacity. Going significantly larger or smaller without re-running the diagnostic testing is not appropriate.
Front Range radon context
Front Range Colorado counties show some of the highest residential radon levels in the US. EPA Map of Radon Zones places most Front Range counties in Zone 1 (highest predicted average indoor radon screening levels). Colorado state data confirms the elevated risk; CDPHE estimates roughly half of Front Range homes have indoor radon levels above the EPA action level of 4.0 pCi/L when properly tested.
Pre-mitigation testing should happen before installing any radon machine. The test confirms the indoor radon level warrants mitigation and provides a baseline against which post-mitigation results can be compared. Front Range homeowners who installed mitigation systems years ago without baseline testing should consider testing now to verify the system is still effective.
New-construction radon-resistant features are increasingly common in Front Range homes built after 2010. The features include a gas-permeable layer under the slab, sealed slab penetrations, and a passive vent stack from the sub-slab area to above the roofline. Homes with these features can typically be activated as full mitigation systems by adding an inline fan to the existing vent stack, often at lower cost than a retrofit installation.
References
- EPA radon information and mitigation guidance — US Environmental Protection Agency
- CDC radon health-effects guidance — Centers for Disease Control and Prevention
- Colorado CDPHE radon program and certified mitigators — Colorado Department of Public Health and Environment
Front Range homeowners with mitigation system questions or fan-replacement needs can get in touch through our contact page for a referral to a certified radon mitigator.