How to Test Your Kootenay Home for Radon: Kit Options, Timing, and What the Result Means

Last updated: 2026-04-26

A long-term radon test kit costs about $40 and is the only way to know your home's actual number. Skipping the test is cheaper than mitigating — but it leaves you guessing on the single most preventable lung cancer risk in a Kootenay home. The BC Interior is one of three Health Canada-named radon hotspots, and town-level test results in Castlegar and Kimberley have come back at roughly 59% above the action level. Knowing your number is the foundation under every decision that follows.

This article covers what to buy, when to put it down, where to put it, what the result means, and when to test again. The pillar page covers the why.

Which test kit should you buy?

Three options, with different jobs.

Long-term alpha-track detector (3–12 months). The Health Canada gold standard for residential testing. The kit is a small disc containing radiation-sensitive film; alpha particles from radon decay leave tracks the lab counts under a microscope. The BC Lung Foundation ships these for about $40, lab fees included. Order online, deploy in your home for a minimum of 91 days, mail it back in the prepaid envelope, results in four to six weeks. This is the kit for almost every first-time test.

Short-term electret or charcoal canister (2–7 days). Quick screening tools that absorb radon over a short window. Useful for a real-estate transaction with a tight close, or a fast read before deciding on a long-term test. Less accurate, because radon levels swing dramatically over short periods. Health Canada explicitly warns that short-term tests should not be the sole basis for a mitigation decision. Typically $30–$80.

Continuous radon monitor ($150–$400). An electronic device that displays rolling daily and long-term averages on an app. Airthings Wave Plus, Corentium Home, and Ecosense RadonEye are the common consumer models. The right tool for ongoing tracking — confirming a mitigation system is working, watching the seasonal swing, or running a multi-year baseline. Overkill for a one-time check.

The right answer for almost any homeowner doing a first test is the long-term alpha-track from BC Lung. Cheap, accurate, recommended by Health Canada.

When to test: the winter timing rule

Test October through April. Health Canada recommends a minimum of 91 days during the heating season because that's when windows are shut, the heat is on, and the stack effect — warm air rising inside the home, drawing replacement air from below — pulls soil gas through every floor crack and service penetration available to it. A winter test gives you a realistic worst-case reading.

Summer tests under-report. Open windows ventilate radon out, and the stack effect weakens. A summer reading of 150 Bq/m³ might be hiding a 250 Bq/m³ winter average — the difference between "no action required" and "Health Canada recommends mitigation within two years."

Deploy the kit when you turn the furnace on for the first cold snap; pull it when you start opening windows again. A 12-month test brackets the entire seasonal swing and produces the most defensible single number you can get.

Where to place the kit

Placement matters because the lab is measuring the air around the detector, not the average air in your home.

• Lowest occupied level — wherever you spend at least four hours a day. Not a crawlspace and not an unfinished mechanical room you only enter to change a furnace filter.
• About 50 cm off the floor, ideally on a shelf or table.
• At least 2 metres from windows and exterior doors — drafts dilute the local concentration and bias the reading low.
• Away from heat registers, fireplaces, and direct sunlight — temperature and humidity extremes can affect the detector film.
• Not in a bathroom, laundry room, or kitchen — high humidity and unusual ventilation patterns skew the reading.

The BC Centre for Disease Control publishes detailed protocols for unusual situations — split-level homes, mixed slab-and-crawlspace foundations, or homes where you split time between two floors.

What the number means

Health Canada uses 200 Bq/m³ as the residential action level. The World Health Organization uses 100 Bq/m³ — a more conservative threshold reflecting the position that no level of radon exposure is risk-free.

• Below 100 Bq/m³. Below WHO's threshold. No action required. Re-test every five to ten years and after any major renovation.
• 100–200 Bq/m³. Above WHO's recommendation, below Health Canada's action level. Some homeowners choose to mitigate at this range, particularly if a smoker lives in the home (radon and tobacco interact multiplicatively). Most opt to monitor and re-test in two to three years.
• 200–600 Bq/m³. Health Canada recommends mitigation within two years.
• Above 600 Bq/m³. Health Canada recommends mitigation within one year.

A single elevated short-term reading should always be confirmed with a long-term test before committing to a $2,500–$4,500 mitigation project. A borderline long-term result (180–250 Bq/m³) is worth re-testing the following heating season — annual variability is real.

After the test

If your number is low, the job is done for this round. Mark your home maintenance calendar and re-test in five to ten years.

If your number is borderline, run a second long-term test the following heating season — ideally with a continuous monitor running in parallel.

If your number is elevated, the next step is a quote from a C-NRPP-certified mitigation specialist. Sub-slab depressurization is the dominant solution and routinely cuts levels by 80–99%. Kootenay Energy doesn't perform mitigation, but we match elevated-result homes to vetted local C-NRPP installers. The installer pays us a small referral fee; you pay them their normal rate.

Re-test cadence

A single test is a snapshot, not a permanent answer. Re-test:

• Every 5–10 years as a routine baseline.
• After any major renovation, especially air sealing or insulation.
• After foundation work — new sump, slab patching, basement waterproofing, weeping tile.
• After installing or modifying ventilation — new HRV, replaced furnace, sealed crawlspace.
• After a mitigation system is installed — every C-NRPP installer should provide a post-mitigation confirmation test, but a homeowner-run alpha-track the following winter is cheap insurance.

The retrofit-and-radon connection

Anyone planning insulation, air sealing, or a deep-energy retrofit should test radon before work begins.

Air sealing concentrates radon. Tighten the envelope and the same leakage paths that were venting warm indoor air to the outside also stop venting soil gas to the outside. Health Canada flags concentration increases of 30–60% in some retrofitted homes — the reason BC's building code, since March 2024, requires a radon rough-in vent pipe in new construction.

Without a pre-retrofit baseline, you can't separate cause from coincidence. A homeowner who tests post-retrofit and finds 280 Bq/m³ has no way to know whether the air sealing pushed a 180 number above the threshold, or the home was always at 280. Pre-retrofit testing answers cleanly. It also lets you mitigate before drywall, flooring, and finished crawlspace membranes go in — which is faster, less invasive, and cheaper than mitigation done afterward.

The same logic applies to heat pump installs that include any envelope work. The kit costs $40. Test now and protect every dollar of the rebate stack downstream.

DIY vs. professional testing

DIY testing — a homeowner-deployed BC Lung kit — is fully appropriate for screening, baseline, and personal-decision testing. Health Canada explicitly endorses homeowner-run long-term alpha-track tests as the standard for residential measurement.

Two situations call for a professional C-NRPP-certified measurement instead:

Real-estate transactions. Buyers, sellers, and lenders want a third-party measurement on file. The chain of custody and detector handling have to be documented by a certified measurement professional. Budget $300–$600.

Post-mitigation verification. After a mitigation system is installed, the confirmation test should be done by a C-NRPP measurement professional using higher-precision tools than the consumer alpha-track market.

For everything else — deciding whether to mitigate, establishing a retrofit baseline, watching seasonal patterns — the $40 BC Lung kit is the right tool.

FAQ

How long do I have to wait for results from a long-term kit? The 91-day minimum measurement period plus four to six weeks for lab analysis. Plan for a four-month window from putting the detector down to receiving a written report by email.

Can I leave the kit out longer than 91 days? Yes — and longer is better. The Radtrak3 detector BC Lung ships is rated for up to 12 months of exposure. A full year captures the entire seasonal swing.

Will opening windows during a test invalidate it? Reduce ventilation as much as is normal for your household — but don't artificially seal everything up. The point is to measure the home as you actually live in it during the heating season.

Does a short-term test ever make sense? For a real-estate close on a tight deadline, yes. For your own peace of mind or planning, the long-term test is always the better choice.

What about testing if I have a heat pump or HRV running constantly? Test anyway. HRVs dilute radon modestly but rarely solve a serious problem on their own. The measurement still reflects your real-world exposure under your real-world ventilation pattern, which is what matters.

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External references:

• Health Canada — Radon Reduction Guide for Canadians
• BC Lung Foundation — Radon Test Kits
• BCCDC Radon Map — interactive map of regional risk patterns across BC
• BCCDC — Radon hub
• C-NRPP — directory of certified measurement and mitigation professionals
• Take Action on Radon — BC

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Kootenay Energy doesn't sell radon test kits and we don't perform testing or mitigation ourselves. We point you to BC Lung Foundation for the kit, and if your result is elevated, we match you with a vetted local C-NRPP-certified mitigation specialist. If you're also planning a heat pump or insulation retrofit, run the calculator to see your rebate stack — and test radon before envelope work begins.