Interactive tool
Should I repair or replace my radon fan?
Four distinct problems present almost identically: a fan at end of life, a fan under warranty, a mounting defect transmitting noise, and a design that never covered the whole slab. Only the first is a replacement decision.
This tree separates them from the symptoms you can observe safely. It never asks you to open a fan housing, touch wiring, or work on a roof discharge.
Work it through
Everything below runs in your browser. Nothing you enter is sent to us or to anyone else — this page has no server to send it to.
The thing that prompted this.
The gauge on the riser.
Since installation or last replacement.
Yes
Check the paperwork rather than guessing.
Yes
Basement finished, HVAC replaced, drain tile or sump added, air sealing done.
Yes
Garage, attic, or exterior wall rather than behind finished surfaces.
What this indicates
Reading your inputs…
Why this says what it says
The full working, shown rather than summarised. Nothing below is hidden behind a toggle, because reasoning that takes a click to reach has not really been shown.
What you told us, and what each answer did
| Your answer | Value | What it influences |
|---|---|---|
| Main symptom | Grinding or rising whine | The thing that prompted this. |
| Manometer reading | Columns offset | The gauge on the riser. |
| Fan age | 7 years | Since installation or last replacement. |
| Believed to be under warranty | No | Check the paperwork rather than guessing. |
| House changed since installation | No | Basement finished, HVAC replaced, drain tile or sump added, air sealing done. |
| Fan is in an accessible location | Yes | Garage, attic, or exterior wall rather than behind finished surfaces. |
What we took on trust
- The figures you enter (fan age) are taken exactly as typed. We have no way to check them against a device or a laboratory record.
- Your answers about main symptom, manometer reading are taken as described. Where a description is approximate the output is approximate in the same way.
- The yes/no conditions (believed to be under warranty, house changed since installation, fan is in an accessible location) are accepted exactly as you set them. Nobody has confirmed any of them, and the output assumes each is as stated.
What is still unknown
- How long your specific fan has left. Service life depends on model, duty, and environment, and any general figure in years would be invented.
- Whether a coverage problem exists behind a high reading. That needs a diagnostic.
Why this stops short of a decision
This runs entirely on what you typed. Nobody has been to your house, nobody has seen the device or the laboratory record, and the choice between courses of action follows from diagnostics performed on the building. What you have here is a reading of what you reported, which is a different thing from a decision and a good basis for making one.
What would change this
- A field survey of installed systems by age, model, and environment would establish real failure-rate curves. What exists publicly is manufacturer warranty terms, which are a commercial commitment rather than a measured service life.
- Measured noise reduction from isolation mounting versus rigid mounting would let this tool tell you how much quieter a fix will actually make the house. We have not found that published.
- Correcting any answer above. Change an input and the output changes, which is the honest behaviour of something working from a description.
The logic, in full
These are the rules the tool applies — not a summary of them. The interactive panel above evaluates exactly this list, and a build check fails if the two ever diverge. A decision tool whose reasoning you cannot inspect is a black box, and a black box is not authority.
| When | Then |
|---|---|
| Fan is silent and the manometer is level | The fan has most likely failed and this is a replacement. Check the breaker first — it costs nothing and explains a meaningful share of dead systems. Replacement is a swap on the existing pipe run. |
| Grinding or a rising whine | Bearing wear, which is the classic pre-failure symptom. This is a replacement rather than a repair; radon fans are sealed units and are not serviced in place. Plan it rather than waiting for silence. |
| Buzzing or humming through a wall with the manometer offset | This is a mounting problem, not a fan problem. The fan is working; its vibration is coupling into framing. Isolation mounts and flexible couplings on the pipe either side are the standard fix and are inexpensive relative to a replacement. |
| Reading is high but the fan appears to be working | Do not replace the fan yet. If the manometer is offset and the fan is audible, the likely issue is coverage rather than the unit — a suction field that does not reach part of the slab. That needs a diagnostic, and a new fan may not change it. |
| Believed to be under warranty | Find the paperwork before ordering anything. Equipment warranty, workmanship warranty, and an outcome commitment are three different instruments, and who administers a claim and whether labour is included are the two things people discover too late. |
| House changed since installation | Retest and get a diagnostic before treating this as a fan question. A finished basement, an HVAC swap, or new drain tile can outrun a design that was correct when installed, and a new fan will not fix a coverage problem. |
| Fan is not in an accessible location | Factor access into the decision. A unit behind finished surfaces turns a routine swap into a larger job, and this is the moment to ask whether relocating it to a garage, attic, or exterior position is worth doing while the work is open. |
| No symptom and the fan is under five years old | Nothing to do. Glance at the manometer monthly and keep the two-year retest habit — those two together catch essentially every failure mode on this page. |
| No symptom and the fan is over ten years old | Budget for replacement rather than reacting to it. These are continuous-duty motors treated as wear items beyond their warranted term, and planning the swap is cheaper than an emergency one. |
| Cannot find or read the manometer | Have a contractor inspect. A system whose indicator cannot be read cannot be checked at all, which is a defect in itself and worth fixing regardless of the fan. |
What this tool cannot do
- This tool reasons from symptoms you can observe safely. It never asks you to open a fan, touch wiring, or work on a roof discharge — those are hazards and, in states that credential radon work, credentialed activities.
- It cannot tell you what a replacement costs. We hold no pricing data.
- It cannot diagnose a coverage problem. That requires sub-slab pressure measurement with instruments a homeowner does not have.
Related
- Is my system working? — The safe checks, in order, and where they stop.
- Do I need a second opinion? — Five situations where a second opinion pays for itself, and one where it does not.
- Should I retest? — Time since the last test, plus what has changed in the house — the two things that decide it.
- Fan noise and vibration — Most radon noise is a mounting problem, not a fan problem — and the fixes are usually inexpensive.
- Fan replacement cost — The one wear item: spotting failure, replacing it, and retesting.
- How long systems last — The pipe is effectively permanent. The fan is the wear item.
- System not working — Diagnose in order: the test, then the fan, then the design. Most "failed" systems fail at one of the first two.
- Mitigation System Component and Service-Life Dataset — What each part does, how it fails, and whether you would notice.
- Radon Mitigation Cost Driver Index — The variables that move a quote, their direction, and their relative magnitude — no invented dollar figures.
- All tools — every calculator and decision tool.
Confidence and limits of this page
Every decision resource on this platform states its own boundaries. This is not a disclaimer — it is the part of this tool you should read before relying on it.
- What we knowClaims on this page we stand behind, each traceable to an approved source or to observable structure.
- Radon fans are sealed continuous-duty units. They are replaced rather than serviced in place, and manufacturers warrant them for a term measured in years.
- Bearing noise — grinding or a rising whine that was not there before — precedes failure.
- Perceived noise is dominated by mounting rather than by the fan, which is why isolation mounts and flexible couplings are the standard remedy for a system audible indoors.
- A manometer reports pressure in the pipe and not concentration in the room, so a working gauge does not establish that the house is below the action level.
- What we do not knowQuestions you may reasonably have that this page does not answer.
- How long your specific fan has left. Service life depends on model, duty, and environment, and any general figure in years would be invented.
- Whether a coverage problem exists behind a high reading. That needs a diagnostic.
- What research would settle itWhat it would actually take to answer the above — naming it is the difference between honesty and hedging.
- A field survey of installed systems by age, model, and environment would establish real failure-rate curves. What exists publicly is manufacturer warranty terms, which are a commercial commitment rather than a measured service life.
- Measured noise reduction from isolation mounting versus rigid mounting would let this tool tell you how much quieter a fix will actually make the house. We have not found that published.
- What we do not claimClaims you might expect to find here and will not, with the reason.
- We do not publish an expected fan lifespan in years, because it depends on factors we cannot see.
- We do not claim a replacement will lower your reading. If the design never covered the slab, a new fan changes very little.
- We do not claim any brand or model is better than another. We do not evaluate equipment.
- What we cannot independently verifyFacts this page relies on that we could not confirm ourselves.
- Your warranty terms, which govern the repair-versus-replace economics more than anything else on this page.
- What your manometer read at commissioning, which is the only baseline your current reading can be judged against.
Sources
- U.S. EPA — Radon
- U.S. EPA — Consumer’s Guide to Radon Reduction
Need a contractor to look at the system?
Free to request and no obligation. We introduce homeowners to credentialed contractors who diagnose before they quote.