Northwest Territories · rules and data checked October 8, 2026

Home health check for Yellowknife

In Health Canada's 2012 survey, 5.4% of 185 homes tested in the Northwest Territories region were above the 200 Bq/m³ radon guideline. Yellowknife's January averages −25.6 °C (ECCC), with about 161 nights a year below −10 °C, when CMHC advises keeping indoor humidity near 30% to stop window condensation. Northwest Territories has no rule we could confirm for carbon monoxide alarms in existing houses.

Radon, 2012 survey

5.4%

above 200 Bq/m³ (185 homes)

Radon, 2024 survey

—

no figure for this area

January average

−25.6 °C

161 nights a year below −10 °C

Private wells

Rare

in Yellowknife

Home health check for Yellowknife

Four quick checks, set up with Yellowknife's winter temperatures and Northwest Territories's alarm rules. Change any value; nothing you enter leaves your browser.

Radon test result

Example value: the Health Canada guideline. Replace it with your own result from a test of at least 3 months.

200Bq/m³ (5.4 pCi/L)

Scale to 800 Bq/m³. 1 pCi/L = 37 Bq/m³.

At the guideline. Health Canada's guideline is 200 Bq/m³; it advises keeping radon as low as reasonably achievable, so consider retesting in the heating season.

Health Canada's lifetime lung cancer risk: for a never-smoker about 1% at low radon, 2% after lifetime exposure at 200 Bq/m³ and 5% at 800; for a smoker 12%, 17% and 30%. Only a test of 3 months or longer gives an annual average; short tests can mislead.

Winter humidity and window condensation
°C
%
Outdoor temperature

January average: ECCC 1981–2010 normals. Cold snap: NRCan's HOT2000 winter design temperature for Yellowknife.

35%highest humidity before the glass fogs at −25.6 °C

Double glazing, clear (1970s–1990s) (U 2.86): condensation starts at about −20.1 °C outside with 40% humidity inside.

Condensation likely. At −25.6 °C outside, the centre of the glass is about 5.0 °C, below the 6.9 °C dew point of 40% humidity at 21 °C.

CMHC: when it is below −10 °C outside, keep indoor humidity at about 30%, and as low as 25% in extremely cold regions. Yellowknife averages 161 nights a year below −10 °C.

Smoke and carbon monoxide alarms

A sleeping area is a group of bedrooms off one hallway.

Smoke alarms required by law
1
Smoke alarms for full coverage (new-home standard)
6
CO alarms recommended
2

We couldn't confirm a Northwest Territories rule for existing houses; install them anyway.

“Full coverage” follows the National Building Code for new homes: one on every storey including the basement, one in each bedroom and one outside each sleeping area, interconnected. CO: NRCan advises one near the furnace or other fuel-burning appliance and one in each bedroom area.

Mould: clean it yourself or call a pro?

Example values shown. 1 m² is about 10.8 sq ft.

Small: you can clean it yourself if you are healthy.

Up to three patches, each under 1 m²: clean with water and unscented dish detergent, wearing safety glasses, an N95 mask and rubber gloves (CMHC). People at risk from mould should not clean it.

Fix the moisture source first. Testing for mould types is usually unnecessary (Health Canada). You entered 2 patches, the largest about 0.5 m².

Yellowknife at a glance

Radon surveys covering Yellowknife
SurveyResult
Health Canada, 2012Northwest Territories, 185 homes, long-term tests5.4% above 200 Bq/m³; 0.5% above 600

The 2024 survey pools long-term tests that households volunteered, so it is not a random sample, and more tests were in basements than in 2012. Health Canada's guideline: fix a home above 200 Bq/m³ within a year. Test kits cost about $30–$80 including the lab; mitigation about $2,000–$3,000.

Highest indoor humidity before windows fog (21 °C inside)
WindowAt −25.6 °CAt −39.2 °C
Single glazing with a storm windowU 2.934%24%
Double glazing, clear (1970s–1990s)U 2.8635%25%
Double glazing, low-e and argon (2000s)U 1.852%43%
ENERGY STAR (U 1.22 or better)U 1.2264%57%
Triple glazingU 1.460%52%

Centre of the glass, from the National Building Code's indoor air film and the Magnus dew point formula. January average from ECCC normals; the cold-snap column is NRCan's winter design temperature. Window edges fog sooner, so follow CMHC: about 30% humidity below −10 °C, which Yellowknife sees on about 161 nights a year.

Smoke alarms in Northwest Territories

The Fire Prevention Regulations adopt the NFC 2020 and NBC 2020 (R-087-2024, in force 2024-10-01), so the NFC rule applies to existing homes.

Existing homes must have them: Yes · Every storey: Not confirmed · In each bedroom: No · Interconnected: No

Law: Fire Prevention Regulations, RRNWT 1990, c. F-12, s. 2(1), as amended by R-087-2024

Official source ↗

Carbon monoxide alarms in Northwest Territories

No territorial requirement to install CO alarms in existing homes was found. The Fire Prevention Regulations (amended by R-087-2024, in force 2024-10-01) adopt the National Building Code 2020 and National Fire Code 2020. Neither the Fire Prevention Act (latest amendments in force 2026-07-02) nor the Regulations contain a CO alarm provision.

No official NWT statement was found that explicitly confirms or rules out a CO alarm requirement for existing homes. Left null.

Official source ↗

Well water in Yellowknife

About 680 Yellowknife residents (roughly 4%) receive the City's trucked water and most others are on its piped system, so private household wells are rare.

  • Bacteria: No GNWT recommendation for private wells found; the Health and Social Services drinking-water page covers community systems only.
  • Chemistry: no provincial frequency published

Northwest Territories source 1 ↗ Northwest Territories source 2 ↗

Radon help in Northwest Territories

New homes: Yes (NBC-based). CBHCC lists the NBC 2020 as adopted in full in the NWT, enforced Oct 1, 2024, so Subsection 9.13.4 (soil-gas barrier and radon rough-in) applies; a territorial source was not checked.

Other help: No NWT radon program was found; Take Action on Radon reports no groups working on radon awareness in the NWT. GNWT said it expects to adopt the 2025 NBC (which adds a passive radon stack) within 18 months of national approval.

Find a C-NRPP certified measurement or mitigation professional at c-nrpp.ca. Data checked October 8, 2026.

Common questions in Yellowknife

How common is radon in Yellowknife?

Health Canada's 2012 survey found 5.4% of 185 homes tested in the Northwest Territories region at or above 200 Bq/m³. Neighbouring houses can differ a lot, so the only way to know is a long-term test of at least 3 months, ideally in the heating season.

What indoor humidity should I keep in winter in Yellowknife?

Health Canada and CMHC advise 30% to 50%, and CMHC says to keep it at about 30% when it is below −10 °C outside (as low as 25% in extreme cold). Yellowknife averages 161 nights a year below −10 °C. At the January average of −25.6 °C, clear double-glazed windows start to fog at about 35% humidity at the centre of the glass, and at about 25% in a cold snap of −39.2 °C; the edges fog sooner.

How many smoke alarms does a house need in Northwest Territories?

The Fire Prevention Regulations adopt the NFC 2020 and NBC 2020 (R-087-2024, in force 2024-10-01), so the NFC rule applies to existing homes. New homes built to the National Building Code need hardwired, interconnected alarms on every storey and in every bedroom, which is the standard we recommend for full coverage.

Are carbon monoxide alarms required in Northwest Territories?

No territorial requirement to install CO alarms in existing homes was found. The Fire Prevention Regulations (amended by R-087-2024, in force 2024-10-01) adopt the National Building Code 2020 and National Fire Code 2020. Neither the Fire Prevention Act (latest amendments in force 2026-07-02) nor the Regulations contain a CO alarm provision.

How we calculate this

Radon

1 pCi/L = 37 Bq/m³ (Health Canada). The Canadian guideline is 200 Bq/m³; above it Health Canada recommends fixing your home within 1 year, sooner the higher the level. Only a long-term test (at least 3 months, ideally in the heating season) tells you your annual average.

Window condensation

glass temperature = indoor − U × (indoor − outdoor) ÷ 8.33

8.33 W/m²·°C is the indoor air film from the National Building Code (RSI 0.12). The dew point comes from the Magnus formula the US National Weather Service publishes; condensation forms when the glass is colder than the dew point. These are centre-of-glass figures: the bottom edge and metal frames run colder, which is why we show CMHC's simpler rule beside them (30% indoor humidity when it is below −10 °C outside, as low as 25% in extreme cold).

Smoke and CO alarms

“Required by law” applies your province's fire code to the layout you enter. “Recommended” is the new-home standard in the National Building Code (an alarm on every storey, in every bedroom and outside sleeping areas) and NRCan's CO advice (one near the furnace or other fuel-burning appliance and one in each bedroom area). Municipal by-laws can add to provincial rules.

Well water and mould

Testing frequencies and lab fees are the ones your province publishes. Mould size categories are Health Canada's and CMHC's: up to three patches each under 1 m² can be cleaned by a healthy homeowner; more than 3 m² needs a professional.

More for Yellowknife

Heating and hot water costs in YellowknifeWhat heating, hot water and air conditioning cost at your local prices, and what each heating system would cost instead.Upgrade payback in YellowknifeSavings, rebates and payback for attic, wall and basement insulation, windows, air sealing and thermostat setbacks.Appliance running costs in YellowknifeWhat your fridge, dryer, freezer and other appliances cost to run at your local electricity price, and what a newer model saves.
Build your upgrade plan → All home services in Yellowknife Radon testing in YellowknifeCarbon monoxide testing in YellowknifeWell water testing in YellowknifeMould testing in YellowknifeVentilation assessments in Yellowknife Northwest Territories rebates and programs

Sources

Prices and programs checked October 8, 2026. Climate: NRCan HOT2000 (Yellowknife) for heating and ECCC 1981–2010 normals (Yellowknife A) for cooling and temperatures.

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