Radon test cost — short-term, long-term, continuous monitor compared

Radon testing falls into three tiers by accuracy and cost. The right tier depends on what you're using the test for: spot-check before action ($20), real-estate transaction ($150-$500), or ongoing monitoring ($200-$500 one-time + free thereafter).

Three test tiers

Tier 1 — Short-term kit ($15-$50)

• Duration: 2-7 days.
• Format: Charcoal canister or alpha-track detector you mail to a lab.
• Accuracy: ±30% on the underlying long-term average.
• Use case: Initial screening before deciding to mitigate. Real-estate transactions in some states.

Reputable brand names: AirChek, Radalink, Pro-Lab. Cost includes the lab analysis and a report mailed back in 1-2 weeks.

Tier 2 — Long-term kit ($50-$120)

• Duration: 90+ days, ideally 12 months.
• Format: Alpha-track detector left in place, mailed at end.
• Accuracy: ±10% on annual average.
• Use case: Most accurate single-measurement number. Used when a short-term test was elevated and you want a confident decision number.

Tier 3 — Continuous radon monitor ($150-$500)

• Duration: Continuous, real-time, reusable.
• Format: Electronic device that reports daily/weekly/monthly averages to a phone app.
• Accuracy: ±10-15%, varies by brand.
• Use case: Ongoing monitoring, post-mitigation verification, multiple-floor measurement.

Brand tier:

• Airthings View Plus / Wave Plus — $250-$400. App-based dashboard. The market leader.
• Corentium Home (now Airthings Home) — $130-$180. Simpler device, screen on the unit, no app needed.
• RadonEye RD200 — $180-$250. Bluetooth, low-cost alternative.
• Generic / Aliexpress — avoid. Accuracy is unverified and many overstate readings.

Real-estate transaction testing

Most state real-estate disclosure laws (PA, IL, NJ, MA, RI, FL, others) require disclosure of any prior testing OR a fresh test as part of the inspection contingency. Specifications:

• Must be done with a state-licensed measurement professional in many states.
• Short-term (48-hour) is acceptable in most states for transactions.
• Closed-house conditions for 12 hours before + during the test.
• Place in lowest livable area (basement if finished; first floor if no basement).

Cost: $150-$300 for a professional measurement service. Cheaper than the buyer's inspector charges if you offer a recent independent test.

What "elevated" actually means

| Reading | EPA guidance | | --- | --- | | < 2 pCi/L | Average US home is 1.3. Mitigation not recommended. | | 2-4 pCi/L | Considered "elevated"; EPA suggests considering mitigation. | | 4-10 pCi/L | At or above EPA action level. Mitigation recommended. | | 10-20 pCi/L | High. Plan to mitigate within months. | | 20-50 pCi/L | Very high. Mitigate ASAP. | | > 50 pCi/L | Severe. Multi-pipe system likely required. Avoid sleeping in basement until mitigated. |

Testing protocol that gets reliable numbers

1. Closed-house conditions for 12+ hours before and during the test. Windows closed, doors closed except entry/exit, HVAC normal.
2. Lowest livable area. Basement if it's finished or you use it; first floor in homes without a usable basement.
3. Place 20+ inches above the floor, away from drafts, away from heat sources.
4. Don't test during storms — barometric pressure swings affect short-term readings.
5. If results are above 4 pCi/L on a short-term test, follow up with a long-term test or a continuous monitor for at least 90 days before deciding the mitigation system size.

Cost-effective testing strategy

For a homeowner deciding whether to mitigate:

1. Day 1: $20 short-term kit. If result is below 2 pCi/L, stop. If 2-10, continue. If above 10, mitigate.
2. Months 1-3: $80 long-term kit OR $250 continuous monitor.
3. Post-mitigation: Continuous monitor stays in place for ongoing verification.

Total cost for 5+ years of reliable data: $250-$350 (continuous monitor wins by year 2).

When NOT to DIY a test

• Real-estate transaction (use a state-licensed measurement professional).
• Insurance claim (need third-party documentation).
• After mitigation install — most contractors include post-mitigation re-test as a $150-$300 line item.

A continuous monitor pays for itself in year 1 if you'd otherwise need 2+ short-term tests. For new homeowners — especially in EPA Zone 1 states — buying a $250 monitor is the highest-leverage single piece of home-health equipment you can install.