Radon tool review
RadonAway RP145C Radon Fan Review
Buy the RadonAway RP145C if you are replacing a failed fan on an existing sub-slab depressurization system of the same specification, because it is the default fan for typical residential systems and the one most mitigation contractors fit. Do not buy it as the starting point for a system you are designing yourself, because RadonAway states plainly that fan sizing for a retrofit may require professional diagnostics, and a fan chosen without them can leave radon levels unchanged while the pipe hums reassuringly.
RadonAway RP145C Radon Mitigation Fan
about $152
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| Spec | RadonAway RP145C Radon Mitigation Fan |
|---|---|
| Inlet and outlet | 4.5 inch diameter |
| Construction | Seams sealed to inhibit radon leakage |
| Impeller | Water-hardened motorized impeller |
| Motor | Thermally protected |
| Rating | Commercial and residential, meets electrical code requirements |
| Naming | RP145C is the manufacturer label for the RP145: same motor, specs and warranty |
Specs come from RadonAway's published product bullets returned by the Creators API. Price is approximate.
What the fan does, and what it does not
An active soil depressurization system draws air from beneath the slab through a suction point and vents it above the roofline, so that the pressure under the slab stays lower than the pressure inside the house and soil gas goes up the pipe instead of through the floor. The fan is the motor of that system. It is not the system. RadonAway’s own bullets say it directly: openings, major cracks and penetrations in the slab or membrane must be sealed for the fan to work, and fan sizing for a retrofit may require professional diagnostics and design. A fan on an unsealed slab moves conditioned air out of your house and very little radon.
Test first, and test again afterwards
Radon is a colourless, odourless radioactive gas and the second leading cause of lung cancer in the United States after smoking, according to the Environmental Protection Agency. You cannot tell whether you have a problem without a test, and you cannot tell whether a mitigation worked without a post-mitigation test. The EPA action level is 4 picocuries per litre. Do not skip either test, and do not accept an installation from anyone who wants to skip the second one. Use a certified radon measurement and mitigation professional, and where your state licenses radon contractors, use a licensed one.
What a full mitigation costs, and where the fan fits
The fan is a small fraction of the total. A complete system includes coring the slab, the suction pit, sealed piping to above the roofline, a manometer, an electrical supply and the labour to route it all through a finished house. Put your own situation into the radon mitigation cost calculator to see where the money goes. Crawl spaces are a related but different job, and sealing one changes the pressure regime under the house, which is why crawl space encapsulation vs vapor barrier cost is worth reading before anyone seals anything: our comparison notes that a fuel-burning appliance inside a crawl space makes sealing a combustion air question for a professional. Price the crawl space work in the crawl space encapsulation cost calculator.
When a replacement fan is the right purchase
Radon fans run continuously and eventually wear out, usually after several years, and the failure is often silent unless you check the manometer on the pipe. If your U-tube manometer has gone level, the fan has stopped. Replacing like for like with the same model is straightforward work for the person who installed the system, and it is the scenario where buying this fan directly makes sense. Retest after the replacement, because the point of the system is a number, not a running fan.
The honest weakness: it is a component, not a solution
The single biggest risk with buying a radon fan online is that it encourages a homeowner to treat mitigation as a plumbing project. Fan selection depends on the suction field the slab and sub-slab material will actually give up, which is measured, not guessed, and an undersized or oversized fan both fail in their own way: too little draw leaves radon in the house, too much can pull conditioned air, waste energy and in some cases affect combustion appliance draft. The fan also cannot be installed inside the living space or below the slab level in most guidance, which constrains where it can go far more than people expect.
What owners consistently report
Published owner reviews describe the RP145 as quiet, long-lived and the model their mitigation contractor originally fitted, with most purchases being replacements rather than first installs. The most repeated caution from owners is about matching the fan to the existing pipe size and to the original system design rather than assuming a bigger fan is better, and several note that they only discovered their old fan had failed when they checked the manometer.
Who it suits
- Like-for-like replacement of a failed RP145 on an existing system
- Contractor-designed systems where the fan has been specified
- Typical residential sub-slab depressurization with 4 inch pipe
Who should skip it
- First-time mitigation without a professional diagnostic and design
- Any situation where the slab has not been sealed
- Crawl space membrane systems that need a different fan specification
- Anyone who has not tested their radon level yet
Safety, stated plainly
Radon is a radioactive gas and the leading cause of lung cancer among people who have never smoked, according to the Environmental Protection Agency. Treat mitigation as health work, not home improvement: test before, test after, and use a certified radon professional, particularly where your state licenses them. The fan must be installed outside the living space so that any leak in the positive-pressure side of the system cannot discharge into the house. Wiring it is electrical work subject to local code, and depressurizing a space that contains a fuel-burning appliance can affect its draft, which is a carbon monoxide question for a qualified professional. Keep a working carbon monoxide alarm in any home with combustion appliances.
Alternatives worth comparing
about $126
Specified where the sub-slab material is tight and the system needs more suction rather than more airflow, which is a distinction that comes out of a diagnostic rather than a catalogue.
View on Amazonabout $268
For systems built with 3 inch pipe, where fitting a 4.5 inch fan would mean rebuilding the pipe run rather than swapping a component.
View on Amazonabout $229
Bundles the manometer and the couplings you need for the swap, which is the practical choice if the existing manometer is also due for replacement.
View on AmazonHow we researched this
We did not test the RadonAway RP145C Radon Mitigation Fan in person, and nothing here is written as though we did. This review is drawn from the manufacturer's published specifications, the product's own documentation, and the consensus of published owner reviews, which is summarised as exactly that rather than presented as our own use. Specifications are sourced as noted under the table above, and prices are approximate and move. Cost figures elsewhere on this site are 2026 estimates, not quotes. This is researched information, not professional advice: anything touching electrical, gas, structural, roofing or hazardous material work should go to a licensed professional and through your local permitting process. For the cost side of this decision, see Full encapsulation vs Vapor barrier only.
Frequently asked questions
Can I install a radon mitigation system myself?
Parts of it are within a competent DIYer’s reach, but fan selection depends on measured sub-slab suction, and RadonAway itself says retrofit sizing may require professional diagnostics and design. Because the outcome is a health measurement rather than a visible result, the sensible path is a certified radon professional, and a licensed one where your state requires licensing.
How long does a radon fan last?
Radon fans run continuously and typically last several years before the motor wears out. Failure is usually silent, so the U-tube manometer on the pipe is how you know: if the fluid levels are equal, the fan has stopped. Check it periodically and retest the house after any fan replacement.
What is the difference between the RP145 and RP145C?
None that affects you. RadonAway states that RP145C is the manufacturer label for the RP145, with the same motor, specifications and warranty. If your existing system uses an RP145, this is the like-for-like replacement.
Does a radon fan work without sealing the slab?
Not properly. RadonAway states that openings, major cracks and penetrations in the slab or membrane must be sealed when installing an active soil depressurization system. An unsealed slab lets the fan pull conditioned air from inside the house rather than soil gas from beneath it, which wastes energy and leaves radon levels largely unchanged.
What radon level requires mitigation?
The Environmental Protection Agency sets an action level of 4 picocuries per litre and suggests considering action between 2 and 4. Those figures come from a long-term test, not a two-day screening. Test first, mitigate on the basis of the result, then test again to confirm the system achieved what it was designed to.