Radon in Your Home:
The Complete Guide
Radon is colorless, odorless, and radioactive. It seeps into millions of homes every year — and most homeowners have no idea it's there. Here's everything you need to test, understand, and fix it.
attributed to radon
What is radon? Radon is a radioactive gas produced by the natural decay of uranium in soil and rock. It enters homes through foundation cracks, floor drains, and construction gaps. The EPA estimates 1 in 15 US homes has elevated radon levels. Testing is the only way to know — you cannot smell, see, or taste it.
All Radon Guides
Signs of Radon in Your House
Where radon comes from, who's at risk, and what the EPA says about exposure limits.
Radon Levels by State
Is your home in EPA Zone 1 (highest risk)? Find your state on the map.
Best Radon Test Kits (2026)
Short-term vs. long-term tests, which labs are certified, and what to do with results.
How to Reduce Radon in Your Home
DIY sealing options vs. professional sub-slab depressurization — costs and effectiveness.
Radon Mitigation Fans: How They Work
Fan types, sizing, installation, and the best models for different foundation types.
Carbon Monoxide vs. Radon
Two invisible killers in the same house — different detectors, different risks, same urgency.
The Connection to House Ventilation
"Burping your house" — the practice of opening all windows for 10-15 minutes to flush stale air — directly reduces radon concentration by diluting indoor air with fresh outdoor air. While this isn't a substitute for professional mitigation at high levels, it's a meaningful daily habit at moderate levels.
Read more about the ventilation technique in our guide on how to burp your house for air quality , or see the full indoor air quality picture in our complete homeowner air quality guide .
Short-Term vs. Long-Term Radon Tests
| Test Type | Duration | Cost | Best For |
|---|---|---|---|
| Charcoal canister (short-term) | 2–7 days | $15–$30 | Quick initial screening or real estate transactions |
| Alpha track (long-term) | 90–365 days | $25–$50 | Most accurate annual average for mitigation decisions |
| Continuous monitor (electronic) | Permanent | $150–$300 | Ongoing monitoring after mitigation installation |
| Professional test | 48 hours | $150–$300 | Required by some lenders; legally defensible results |
⚠️ Radon & Real Estate
If you are buying or selling a home, radon testing is often required or strongly recommended. A level above 4 pCi/L discovered during inspection gives buyers legal leverage to request mitigation as a condition of sale. Mitigation systems typically cost $800–$2,500 and can be negotiated into the sale price.
☢️ The Ventilation Connection
Tightly sealed modern homes trap radon more efficiently than older, leaky homes. This is the same "Stack Effect" that makes modern homes noisier in winter — the same air pressure dynamics that push radon in also move it around. Learn how the Stack Effect works .
Frequently Asked Questions
How long does radon mitigation last?
A properly installed sub-slab depressurization system lasts 10–20+ years. The fan may need replacing every 5–10 years (~$150–$300). You should retest every 2 years or after major renovations to confirm effectiveness.
Does opening windows reduce radon?
Yes, temporarily. Opening windows (burping the house) dilutes radon by bringing in fresh air. However, it's not a permanent solution because radon continuously seeps in. It's a useful daily habit at moderate levels (2–4 pCi/L) but not sufficient above 4 pCi/L.
Can I install a radon mitigation system myself?
In most states, yes — there's no law requiring a licensed contractor for DIY installation. However, improper installation can actually increase radon levels. For levels above 8 pCi/L or complex foundation types (crawl space, block walls), professional installation is strongly recommended.