Short answer
Probably not, and it can make things worse. An exhaust fan pushes basement air outdoors, and the make-up air that replaces it can pull more soil gas, and radon, in through the foundation. The fan that does work is a radon mitigation fan, which draws radon from under the slab and vents it above the roof.
Next step: a certified professional designs and installs the fix. Find a mitigation professional
A house usually sits at lower pressure than the soil around it, which is what draws radon in. Exhaust fans, dryers and other appliances that remove air add to that pull, so exhaust ventilation alone is a weak and uncertain way to lower radon.
A
What to do next: test with the house closed up; if the result is high, get estimates for a sub-slab system from certified mitigation professionals.
At a glance · 1 min read
A house already runs at slightly lower air pressure than the soil around it, and that difference is what pulls radon in through cracks and openings in the foundation. An exhaust fan pushes indoor air out. The air that replaces it has to come from somewhere, and some of it comes from the soil. So a fan blowing basement air outdoors can drive more soil gas, and more radon, into the house.
| Effect | What happens |
|---|---|
| The house as a vacuum | Indoor air pressure is usually lower than in the soil, so the house draws radon in through foundation openings |
| Exhaust fans and appliances | Exhaust fans, dryers, water heaters and fireplaces remove air, which can drive soil gas in as make-up air enters the lower part of the house |
| Stack effect | Warm air escapes high up, and make-up air, some of it from the soil, enters low down |
That is why ventilation by itself is a weak and uncertain tool against radon, and why a do-it-yourself fix without the right knowledge can actually raise the level.
In a picture · 1 min read
A radon
| Aspect | Basement exhaust fan | Radon mitigation fan |
|---|---|---|
| Pulls air from | The basement room | The soil under the slab, through sealed piping |
| Effect on pressure | Lowers indoor pressure, which can draw soil gas in | Creates a vacuum under the slab, which keeps soil gas out |
| Where it sits | In the living space | Never in or below a livable area; usually an attic, garage or outside |
| How it runs | On and off | Continuously; it must never be turned off |
| Typical reduction | No typical reduction is given for it | Subslab suction typically lowers radon 50 to 99 percent |
In a picture · 1 min read
Some ventilation methods are recognized for radon, but they work differently from an exhaust fan, and all of them rank behind soil suction.
Typical radon reduction, EPA
Basement and slab-on-grade homes
Crawlspace homes
Any type of home
| Method | How it differs from an exhaust fan | Limits |
|---|---|---|
| House or basement pressurization | A fan blows air into the basement to raise its pressure and hold radon out | Limited by construction, climate, appliances and lifestyle; lowest-level doors and windows must stay shut; moisture and energy penalties; only after common methods fall short |
| Heat recovery ventilator | Balanced: brings in outdoor air while exhausting indoor air, recovering heat | Variable effect; best in the basement only; must run all the time; raises heating and cooling costs |
| Opening windows | Mixes outdoor air with indoor air rather than pushing air out | Temporary: levels most often return within about 12 hours of closing up |
At a glance · 1 min read
During a
| Fan | During the test |
|---|---|
| Radon system fan | On, for the whole test |
| Small exhaust fans for short periods | Allowed |
| Fans or machines that bring in outside air | Off |
More on what affects a reading is in what can affect a radon test.
Questions · 1 min read
It can. Exhaust fans remove air from the home, and the make-up air entering the lower part of the house can bring soil gas, and radon, in with it.
That is house pressurization, a recognized technique, but its effect is limited by construction, climate and how the home is used, and it is tried only after the common methods have not lowered radon enough.
Fans and vents that circulate air are among the steps suggested for keeping radon low in a home below the action level, but this kind of ventilation is only temporary and is not considered radon mitigation.
Because the exhaust fan must not be located in or below a livable area. Common locations are unconditioned spaces such as attics and garages, or the outside of the home.
A qualified contractor is recommended, because without the right equipment and knowledge you could increase the radon level. See do-it-yourself radon mitigation.
It is something contractors look at: a contractor may have concerns about backdrafting of combustion appliances when planning radon work, and may recommend having them checked by a qualified inspector.
How a mitigation system brings a high level down, the fan that runs it, and what it costs.
What gets rid of radon, how reduction and abatement work, and what they cost.
Read the guideHow a radon mitigation fan works, where it goes, what it costs to run and replace.
Read the guideHow mitigation systems reduce indoor radon, when to mitigate instead of retest, what a project involves, common mistakes, and how to confirm a system actually worked.
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