Radon Mitigation Cost Calculator
Estimate the cost of a radon mitigation system from your own quote — base system by foundation type plus any extra suction points, with a contingency buffer.
Calculator
A base radon system of $1,200.00 plus 1 extra suction point at $500.00 each is about $1,870.00. Radon is a serious health risk (EPA action level 4 pCi/L). Test first and use an NRPP/NRSB-certified mitigator. A cost estimate, not a diagnostic.
A radon mitigation system lowers indoor radon by continuously drawing soil gas from beneath the slab and venting it above the roofline — the standard approach is active sub-slab depressurization (a sealed suction point under the floor, a sealed vent pipe and an inline fan). The price of a system is driven mostly by the foundation type (slab-on-grade, full basement or crawlspace), the number of suction points a large or divided slab needs, and access for routing the vent stack. This calculator turns the quote in front of you into a clear line-item total — it does not set the price, so enter the figures from your own contractor.
Formula
Total = (base system + extra points × price per point) × (1 + contingency%)
- Base system — the quoted price for a single-fan sub-slab system on your foundation.
- Extra suction points — extra draw points a big or compartmented slab needs; each adds pipework and sealing.
- Contingency — a buffer for hidden conditions (hard routing, sealing cracks, a sump to cover).
The identity is er_contingency_total(base + extra, pct) from the tested calculation library; it is exact arithmetic, not a price index.
Worked example
A full-basement home is quoted a $1,200 base system. The slab is divided by a footing, so the contractor adds 1 extra suction point at $500, and you keep a 10% contingency for sealing the sump and a few floor cracks:
(1,200 + 1 × 500) × 1.10 = 1,700 × 1.10 = $1,870
So budget about $1,870. A simple slab-on-grade system with good sub-slab gravel is often cheaper; a crawlspace needing a sealed sub-membrane runs higher. Always retest after install to confirm the level is below the EPA action level of 4 pCi/L.
How radon systems are priced & what to check
Radon is a naturally occurring radioactive gas and the second-leading cause of lung cancer in the United States. The EPA action level is 4 pCi/L: at or above it, mitigation is recommended, and many professionals suggest acting between 2 and 4 pCi/L as well. Because health risk is involved, this tool is deliberately a cost estimator only — it is not a diagnostic and not a health opinion. Test first with a proper short- or long-term test, and use a mitigator certified by the NRPP or NRSB.
When you compare quotes, look past the headline number: a good system is sealed (slab penetrations, sump lids and major cracks), routes the fan and vent so the discharge is above the eave and away from windows, and includes a visible system-failure indicator (a manometer). Ask whether a post-mitigation test is included — a system is only proven by a follow-up measurement under 4 pCi/L. Fan replacement every several years is a small recurring cost the base price will not include.
Foundation type is the single biggest cost driver, which is why the bands in the reference table are grouped that way. They are labeled planning bands — a sanity check against the quote you enter, never a live rate. Local geology, radon level and pipe routing move the real number, so a certified mitigator’s written scope is the source of truth. For the fan class itself, use the companion radon fan sizing helper.
Reference table
Labeled planning bands for a single-fan sub-slab system by foundation type — a sanity guide only; enter your own quoted price. See the full radon, asbestos & lead cost table.
| Foundation | Typical base system |
|---|---|
| Slab-on-grade | $800 – $1,500 |
| Full basement | $1,000 – $2,000 |
| Crawlspace (sub-membrane) | $1,500 – $3,500 |