What's the difference between short-term and long-term radon tests?

Short-term radon tests run for 2 to 7 days and give you a quick snapshot of radon levels in your home. Long-term tests run for 90 days to a year and measure your average radon exposure over time, which is more accurate for health decisions since radon levels fluctuate seasonally.

Are home radon test kits accurate?

Yes, EPA-approved radon test kits are accurate when used correctly. The key is following placement instructions (basement or lowest lived-in level, away from drafts) and sealing doors/windows during the test period. Lab analysis of charcoal canisters and electret ion chambers is reliable.

Which radon test kit brand is best?

Pro-Lab, First Alert, and RadTrak are among the most trusted EPA-approved brands. Pro-Lab offers excellent charcoal canisters and alpha track detectors with fast lab turnaround. First Alert provides affordable short-term kits. Choose based on test duration, price, and your comfort with lab shipping.

How do I know if my radon level is dangerous?

The EPA action level is 4.0 picocuries per liter (pCi/L). If your test result is 4.0 or higher, the EPA recommends taking action to reduce radon. Even levels between 2 and 4 pose some risk, and you may want to consider mitigation.

Best Radon Test Kits for Home Use (Short & Long Term)

The best radon test kits for your home are Pro-Lab Radon Gas Test Kit (long-term), First Alert Radon Test Kit (short-term, budget), and RadTrak Continuous Radon Monitor (real-time digital readings). Your choice depends on whether you need quick results (2–7 days) or accurate long-term data (90+ days), your budget, and whether you prefer mailing samples to a lab or getting digital readings instantly.

Radon is a colorless, odorless radioactive gas that seeps into your home from soil and rock beneath your foundation. It's the second leading cause of lung cancer after smoking, and the EPA estimates one in three homes has radon above safe levels. Testing is your only way to know if your house has a problem.

But which test kit actually works? And should you choose a quick test or wait three months for accurate data? Let's break down your options.

Short-Term vs. Long-Term Radon Tests: What's the Difference?

Radon levels in your home change with the seasons, time of day, and weather. This is why testing duration matters.

Short-Term Tests (2–7 Days)

A short-term test gives you a snapshot of radon in your home right now. You place the kit in your basement or lowest lived-in level, seal windows and doors, keep it undisturbed for 2 to 7 days, then mail it to the manufacturer's lab. Results come back in 1–2 weeks.

Pros: Fast results, affordable ($15–$40), good for initial screening, useful if you're selling a house quickly.

Cons: Results can fluctuate wildly. A short-term test might show 2 pCi/L one week and 8 pCi/L the next, depending on weather and how tightly you sealed your home. The EPA recommends treating short-term results as a preliminary indicator only.

Long-Term Tests (90 Days–1 Year)

A long-term test (usually 90 days) measures your average radon exposure across seasons. You place the detector, leave it alone for three months, then mail it in. This gives a much more reliable picture of your true radon risk.

Pros: Highly accurate, accounts for seasonal variation, ideal for making mitigation decisions, results hold more weight if you're buying or selling.

Cons: Takes longer, costs more ($30–$60), requires patience.

Bottom line: If you suspect radon or want peace of mind, use a long-term test. If you need answers fast for a real estate transaction, start with short-term but follow up with long-term.

Top Radon Test Kit Brands & Our Recommendations

Brand & Model	Test Type	Duration	Price	Lab Turnaround	Best For
Pro-Lab Radon Test Kit (RK-311)	Charcoal Canister	2–7 days	$18–$25	5–7 days	Quick screening, budget-conscious
Pro-Lab Alpha Track Detector (RD-200)	Alpha Track (Long-term)	90 days	$35–$50	7–10 days	Accurate baseline, best accuracy
First Alert Radon Test Kit	Charcoal Canister	2–7 days	$10–$18	5–7 days	Budget option, initial test
RadTrak Continuous Radon Monitor (RTM2201)	Digital Electret Ion Chamber	Real-time (optional 3–7 day test)	$150–$200	None (no lab needed)	Professionals, detailed data, instant results
Accustar Labs SADC-2000 (Mail-in)	Charcoal Canister	2–7 days	$15–$22	7–10 days	Basic home screening

Pro-Lab Radon Test Kit (RK-311) — Best Overall Short-Term

Pro-Lab's charcoal canister is the gold standard for DIY radon testing. It's EPA-approved, widely available, and affordable. You place it in your basement for 2–7 days (the longer, the better), seal it in a bag, mail it to Pro-Lab's North Carolina lab, and get results in 5–7 days. The kit comes with all instructions and a prepaid return mailer.

Real homeowners report quick turnaround and clear result letters. The main limitation is that it's a snapshot—if you get 3.8 pCi/L, you won't know if that's typical or a fluke.

Pro-Lab Alpha Track Detector (RD-200) — Best Long-Term Test

If you want the most accurate picture of your home's radon risk, the alpha track detector is your answer. It sits passively in your home for 90 days (or longer), recording every alpha particle from radon decay. After three months, you mail it in, and the lab counts the tracks microscopically.

The result is your true average radon level, not a lucky or unlucky week. It costs $35–$50, which is only slightly more than two short-term tests, but the accuracy is much higher. Lab turnaround is 7–10 days.

First Alert Radon Test Kit — Best Budget Option

At $10–$18, First Alert's charcoal canister is the cheapest EPA-approved option. It's not fancy, but it works. Use it the same way as Pro-Lab: place it for 2–7 days, seal it, mail it. Results take 5–7 days.

Good for a preliminary screening if you're not sure whether to invest in long-term testing. Keep in mind that at this price, you're paying for basic accuracy—don't expect premium customer service.

RadTrak Continuous Radon Monitor (RTM2201) — Best for Digital Data

This is the professional-grade option. Unlike passive tests, RadTrak is an electronic detector that displays radon levels in real-time on a digital screen. It measures in picocuries per liter (pCi/L) continuously.

You can watch your radon levels change throughout the day and week, which helps you understand how ventilation and weather affect your home. Some models also allow you to conduct a 3–7 day test and record data for your own records (no lab needed). At $150–$200, it's more expensive upfront, but invaluable if you're a homeowner who likes data or you're considering a mitigation system.

How to Use a Radon Test Kit Correctly

Accuracy depends on following the rules. Radon testing is simple, but mistakes kill your results.

Place the kit in the lowest lived-in level. Usually your basement. If you live in a basement apartment, put it there. If you're testing a single-story home with no basement, use the ground floor living room.
Position it at least 12 inches from walls. Radon needs to circulate around the detector. Don't jam it in a corner or closet.
Keep it away from drafts, vents, and exterior doors. No direct sun, no AC blowing on it, no open windows. Drafts will push radon out of the detection zone.
Seal your home. Close windows and doors. Don't turn on exhaust fans, range hoods, or humidifiers. For short-term tests, maintain "closed-house conditions" for the entire test period.
Leave the kit undisturbed. Don't touch it, move it, or open it during the test.
Mail it promptly after the test ends. Don't wait a week—seal it immediately and send it to the lab.

Violating these rules—especially drafts and leaving doors or windows open—can deflate your readings and give you a false sense of security.