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Indoor Humidity in Winter: Spot Signs and Restore Healthy Home Air

Humidity indoors can be just as problematic as outdoors, especially during winter. It fosters mold growth, respiratory issues, eye and nasal irritation, headaches, and fatigue—particularly in children and the elderly. The good news: proven strategies can effectively manage it.

Spotting the Signs of Excess Humidity

Humidity issues are common in winter and easy to recognize. Key indicators include:

  • mold, found in 14 to 20% of French homes according to ANSES
  • condensation on windows
  • peeling paint and wallpaper
  • walls that feel damp to the touch
  • musty odors from cupboards
  • a persistent chill
  • presence of psocids (booklice)

For precise measurement, use a hygrometer. European guidelines recommend ideal levels between 30 and 70%.

Address the Root Causes

Indoor humidity stems from various sources—identifying them is key to effective solutions. Leaks and infiltrations are frequent culprits, affecting pipes, walls, or roofs. Repair any leaks promptly.

For facade infiltrations, apply a water-repellent treatment. Capillary rise from foundations often requires professional work to isolate the structure from groundwater.

In milder cases, opt for targeted fixes: dehumidifiers, better ventilation, waterproofing vulnerable walls, or mold treatments.

Indoor Humidity in Winter: Spot Signs and Restore Healthy Home Air

Adopt Habits That Reduce Moisture

Daily routines can exacerbate humidity—simple changes make a big difference. In bathrooms, shorten showers and baths, and use moderate water temperatures to prevent mold on joints.

Ventilation is crucial year-round: ensure VMC systems function properly if no windows are available. In the kitchen, cover pots, always use the extractor hood when boiling, and let water evaporate fully.

Maintain even heating at around 19°C to avoid cold spots. For drying laundry, choose a ventilated space or a dryer over indoor hanging.

Humidity varies by home, but from ventilation tweaks to structural repairs, tailored actions ensure clean, healthy indoor air.