# RadonAway RP145 Radon Fan: Sizing, Replacement & Service

- **URL:** https://airsenseenvironmental.com/radonaway-rp145-radon-fan/
- **Published:** 2026-08-26

Skip to content Radon Mitigation Services ▾ Radon Testing Commercial Radon Mitigation Commercial Radon Testing Indoor Air Quality Crawl Space Encapsulation Service Area Resources FAQ Blog Podcast Reviews & Projects About Us Contact 314-664-9807 Free Estimate Radon Mitigation Services Radon Testing Commercial Radon Mitigation Commercial Radon Testing Indoor Air Quality Crawl Space Encapsulation Company Service Area Resources FAQ Blog Podcast Reviews & Projects About Us Contact Call 314-664-9807 Fan Guide · St. Louis Metro RadonAway RP145 Radon Fan: Sizing, Replacement & Service 4-Inch Fan 34 to 66 Watts Professional Diagnostics The RP145 is a common inline radon fan, but the model number alone does not tell you whether it is right for your home. Air Sense Environmental evaluates and replaces radon fans across St. Louis, MO, St. Louis County, St. Charles County, and the Illinois Metro East, including systems installed by other contractors. Call 314-664-9807 Schedule a Fan Evaluation IEMA License #RNM20232346 Any Brand Serviced Missouri & Illinois RP145 at a Glance Published airflow at 0.5" WC124 CFM Published airflow at 1.0" WC81 CFM Airflow drops as system resistance rises. Proper sizing requires diagnostics at the home. RadonAway part 28461 Quick Answer What Is the RadonAway RP145? The RadonAway RP145 is a continuously operating radon mitigation fan in the RP Pro Series. It connects to 4-inch radon vent piping and creates suction that pulls radon-bearing soil gas into the vent system before the gas enters the home. RadonAway lists the RP145 as part number 28461 and rates it for residential and commercial use. The current manufacturer page describes a thermally protected, water-hardened motorized impeller, sealed housing, and indoor or outdoor listing. The fan carries a five-year limited manufacturer warranty, subject to the manufacturer's terms. The fan is only one component of the system. The suction point, vent piping, couplings, electrical connection, manometer, discharge location, and seals must work together for the system to reduce radon effectively. See how a complete radon mitigation system works. If an RP145 is noisy, has stopped running, or is not keeping the home below the EPA action level of 4.0 pCi/L, the fan and the system around it should be evaluated. Manufacturer Data RadonAway RP145 Specifications RadonAway's current RP Pro Series performance data shows how airflow changes as resistance, or static pressure, increases. 4 in.Nominal duct connection 34 to 66 WPublished power range 1.7" WCRecommended max operating pressure 169 CFMTypical airflow at 0" WC Static pressurePublished typical airflow 0.2 inches water column150 CFM 0.5 inches water column124 CFM 1.0 inch water column81 CFM 1.5 inches water column42 CFM Source: RadonAway RP Pro Series fan performance data. These numbers help compare models, but they do not replace pressure-field diagnostics. A fan that looks sufficient on a chart can still be poorly matched to compact soil, multiple foundation sections, restrictive piping, or a large footprint. A complete replacement includes more than the fan body. Couplings, piping, electrical connections, and system performance all need to be checked. System Fit Is the RP145 the Right Fan for My Radon System? The RP145 may fit many residential sub-slab or sub-membrane systems, but a contractor should verify the operating conditions before selecting it. Pressure shown by the system manometer Airflow and resistance at the existing suction point Number and location of suction points Basement, slab-on-grade, crawl space, or mixed foundation Pipe diameter, length, turns, and discharge route Radon level before and after the fan operates Noise and vibration at the fan location A larger fan is not automatically better. Oversizing can increase noise and energy use, pull conditioned air through gaps, or place the fan outside its intended operating range. Undersizing can leave parts of the foundation without enough negative pressure. The goal is the correct fan for the tested system, not the highest airflow number. Compare the main types of radon mitigation systems. Replacement Can an RP145 Replace My Existing Radon Fan? Sometimes, but a replacement should not be chosen only because the pipe connections appear to match. If the original system was designed correctly and the home's structure has not changed, a like-for-like replacement may be reasonable. A different model may be more appropriate if the old fan was poorly sized, the system has multiple suction points, the basement was remodeled, a crawl space was added, or post-mitigation testing was never completed. During a professional replacement visit, the technician should inspect the fan, couplings, vent piping, electrical disconnect, manometer, discharge location, and visible system seals. After startup, the technician should verify suction and recommend a radon test to confirm the result inside the home. Learn about radon fan replacement in St. Louis. Homeowner Checks How Do I Know if My RP145 Is Working? Start with the U-tube manometer or other system warning device. The liquid columns normally sit at different heights when the fan is creating suction. A level reading can mean the fan has stopped, power is off, or the system is no longer creating measurable pressure. Also pay attention to a fan that becomes much louder than usual, develops grinding or rattling noises, cycles unexpectedly, or stops producing airflow at the discharge. Do not use sound alone as proof that the system is reducing radon. A U-tube manometer shows whether the system is creating pressure. It does not measure the radon concentration in the home. The EPA advises homeowners to check the warning device regularly and retest at least every two years to confirm that radon levels remain low. The manometer measures system pressure, not indoor radon concentration. Read the radon mitigation system maintenance guide. Operating Cost How Much Electricity Does an RP145 Use? RadonAway publishes a 34-to-66-watt operating range for the RP145. Actual energy use depends on where the fan operates on its pressure curve, and local utility rates determine the cost. Because an active radon fan must run continuously, a technician should choose the lowest-power fan that still provides the required pressure and airflow for the home. Turning the fan off is not an energy-saving solution because the mitigation system stops working without suction. Estimate how much electricity a radon mitigation fan uses. Professional Service Should I Replace an RP145 Myself? Fan replacement affects the performance and safe discharge of a radon mitigation system. Matching the pipe diameter is only one part of the job. The new fan must be compatible with the system's pressure and airflow requirements, installed in an allowed location, connected correctly, sealed against leakage, and checked after startup. Professional service also gives you a chance to identify why the old fan failed. Excessive moisture, restricted piping, loose couplings, vibration, or a fan operating outside its intended range can shorten service life or reduce performance. The final step is a radon test. The manometer shows that the system is creating suction. It does not measure the radon concentration in the home. Learn about post-mitigation radon testing. Common Questions Frequently Asked Questions About the RadonAway RP145 Is the RadonAway RP145 a 4-inch fan? Yes. RadonAway publishes a 4-inch nominal duct connection for the RP145. The existing pipe size still does not confirm that the model is correctly sized for the system's resistance and airflow needs. How many watts does an RP145 use? RadonAway publishes an operating range of 34 to 66 watts. The actual draw depends on the fan's operating point and the resistance in the mitigation system. How much air does an RP145 move? RadonAway lists 169 CFM at zero static pressure, with lower airflow as resistance increases. Published typical airflow is 124 CFM at 0.5 inches water column and 81 CFM at 1.0 inch water column. Does the RP145 have a warranty? RadonAway lists a five-year limited warranty for the RP145. Coverage depends on the manufacturer's current warranty terms and the installation conditions. Can I replace an RP145 with a different model? Possibly. A contractor should compare operating pressure, required airflow, pipe layout, foundation, noise conditions, and radon test results before selecting a different fan. Why is my RP145 fan loud? New grinding, rattling, humming, or vibration can point to worn bearings, loose couplings, pipe vibration, moisture, or an operating condition that needs inspection. Does a moving manometer mean my radon level is safe? No. The manometer indicates pressure in the system, not the radon level in the house. A radon test is the only way to confirm indoor concentration. The EPA recommends action at 4.0 pCi/L or higher and recommends retesting at least every two years after mitigation. Can Air Sense Environmental service a system installed by another company? Yes. Air Sense Environmental's radon fan replacement service covers systems installed by other contractors as well as systems we installed. Technical references: RadonAway RP145 product page, EPA system-maintenance guidance, and EPA radon action-level guidance. Local Coverage RP145 Fan Service Across the St. Louis Metro Air Sense Environmental services radon mitigation systems throughout St. Louis, MO, St. Louis County, St. Charles County, Jefferson County, Franklin County, Madison County, and St. Clair County. We work on systems we installed and systems installed by other contractors. If you have an RP145 or another radon fan model, send us a photo of the fan label, the manometer, and the visible piping when you request service. Those photos help us prepare, but we will still verify system conditions before recommending a replacement. Fan Evaluation RP145 stopped or suddenly noisy? We can evaluate the fan and the system around it, then recommend the correct replacement for the home's tested conditions. 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