Most people in Germany know the basic risks of air pollution and mould—but radon is the invisible threat many still underestimate. Recent regional surveys and wintertime indoor-stay patterns have driven searches for “radon” up; that’s not surprising given how quickly exposure risk can change with ventilation and building use. This guide explains what radon is, why it matters now, who should act first, and exactly how to test and fix high levels (practical steps you can take this week).
What is radon and why it matters
Radon is a naturally occurring radioactive gas produced by the decay of uranium in soil and rocks. It’s colourless, odourless and can accumulate in basements and ground-floor rooms. Long-term exposure to elevated radon concentrations increases lung cancer risk; the World Health Organization classifies radon as a carcinogen. For a concise technical overview see Radon — Wikipedia.
Why this is trending in Germany right now
Two factors explain the current spike in interest: seasonal behaviour and renewed regional surveys. In colder months homes are sealed more tightly, raising indoor radon. Second, several states and municipalities have publicized measurement campaigns and preliminary maps, prompting homeowners to search for local guidance. The German Federal Office for Radiation Protection (BfS) has also updated resources and recommended action thresholds, which increased public attention.
Who is searching and what they need
Search intent breaks down into three groups: homeowners and tenants (everyday people worried about health), building professionals and landlords (responsible for compliance and remediation), and health-conscious residents in affected regions. Most are beginners: they want to know if they should test, how to test, and what mitigation costs look like.
How radon exposure is measured
Radon is measured in becquerels per cubic metre (Bq/m³). Short-term detectors (2–7 days) and long-term detectors (90+ days) are available. Long-term tests give a more reliable assessment because radon fluctuates daily and seasonally. Certified labs and providers analyze passive devices (alpha track detectors) or provide electronic monitors for continuous readings.
Action thresholds and regulations in Germany
German guidance typically recommends action when indoor radon exceeds certain levels; consult local BfS advice for current thresholds. For international context and health-based limits see the WHO fact sheet on radon: WHO Radon Fact Sheet. Building regulations and recommended reference levels often differ by federal state, so check municipal guidance if you’re assessing legal obligations.
Quick self-check: who should test first?
- Homes with basements or ground-floor bedrooms.
- Properties built on known uranium-bearing geology (granite regions, certain clay-rich soils).
- Recently renovated buildings where ventilation patterns changed.
- Purchasing or selling property in a region with known elevated radon.
Step-by-step testing plan (practical)
- Order a long-term passive detector from a certified lab (90+ days) or rent an electronic monitor if you need quick feedback.
- Place detectors in the lowest lived-in level and at least one upper-floor bedroom if applicable. Avoid drafts, windows and direct sunlight.
- Record start/end dates and living conditions (heating, ventilation patterns).
- Send detectors to the lab or download logs from the monitor and compare to recommended action levels.
Mitigation options: pros and cons
When tests show elevated radon, technicians typically recommend one or more of the following:
- Sub-slab depressurization (active soil depressurization): most effective for houses with crawlspaces or concrete slabs; higher upfront cost but durable results.
- Increased ventilation: cheaper short-term solution (heat-recovery systems recommended to avoid energy loss), but may not reduce levels sufficiently in severe cases.
- Sealing of entry points: reduces migration paths but is usually supplementary to depressurization.
- Pressurization/ventilation of basements: can be effective in some building types but requires careful design to avoid moisture issues.
Cost considerations and timelines
Costs vary widely: DIY ventilation changes can be low-cost; professional depressurization systems typically run from a few hundred to several thousand euros depending on house size and complexity. In my practice, budget for diagnostic testing (100–300€), and remediation (1,000–6,000€ typical for single-family homes) as a working range—get multiple quotes from certified installers.
Professional credentials and quality control
Hire technicians certified by recognized bodies; ask for before/after measurements and guarantees. Look for installers with documented experience in sub-slab systems and measurable post-remediation reductions. Independent lab testing should be used for verification.
Case example (typical outcome)
In dozens of projects I’ve reviewed, active sub-slab systems reduce radon by 80–95% on average when correctly installed. Short-term fixes like window ventilation sometimes lower levels temporarily but tend to rebound in winter. Long-term monitoring after remediation is essential to confirm sustained improvements.
Practical checklist: what to do this month
- Buy or order a long-term detector and place it in the lowest lived-in area.
- Document living conditions and building use while testing.
- If levels exceed local guidance, contact certified testing providers for diagnostic follow-up.
- Get at least two remediation quotes and request post-work verification testing.
What success looks like and next steps
Success is a verified reduction below the recommended action level with a maintenance plan and periodic rechecks (every 2–5 years or after structural changes). Keep documentation for future buyers or insurers.
Further reading and authoritative resources
For technical detail and policy, consult the German Federal Office for Radiation Protection (BfS) and the WHO radon guidance referenced above. For a factual overview and history see Radon — Wikipedia.
How you act now matters: testing is inexpensive relative to health risk and remediation is effective when done by professionals. If you want, start with a long-term detector this season and plan follow-up diagnostics if results are above the recommended threshold.
Frequently Asked Questions
Action levels vary by guideline; authorities often recommend remediation when long-term indoor radon exceeds their reference value. Check local BfS guidance and aim for levels as low as reasonably achievable.
Use a long-term detector (90 days or more) for representative results because radon fluctuates daily and seasonally. Short-term tests can be useful for screening but are less reliable.
Active sub-slab depressurization is the most consistently effective method for slab-on-grade or crawlspace houses. Complementary techniques (sealing, balanced ventilation) may be used depending on construction.