Summer cottage ventilation

Stale air in a summer cottage?

A musty smell is a familiar experience in many summer cottages and is often a sign of inadequate ventilation. When the air is not properly exchanged, indoor air becomes stale and moisture begins to condense on surfaces. A musty smell does not necessarily indicate that the cottage has moisture damage, but it does suggest that the conditions are favourable for moisture-related problems to develop.

Even an older summer cottage can be upgraded by installing a sufficient number of fresh air valves to provide effective and controlled ventilation.

Improving ventilation in a summer cottage

According to Statistics Finland, there are more than half a million summer cottages in Finland. More than 70% of them were built before 1990. Cottage construction peaked during the 1980s, when more summer cottages were built than in any other decade.

Many older summer cottages lack fresh air valves altogether. Without them, replacement air enters the building uncontrollably through gaps in the structure and insulation. This can affect both indoor air quality and the condition of the building. Opening windows provides only a temporary improvement in ventilation and often allows insects, such as mosquitoes, to enter the cottage.

Ventilation is needed all year round

A musty smell in a summer cottage develops when indoor air remains stagnant and moisture is allowed to accumulate on furniture, textiles, and other surfaces. One of the primary functions of ventilation is to remove excess moisture. Ventilation is needed throughout the year, even when the cottage is unoccupied during the winter. If a building remains unused for long periods without adequate ventilation, moisture cannot escape and instead accumulates within the building structure.

Many cottage owners have become accustomed to stale indoor air and may not recognize the signs of inadequate ventilation. If the air in the bedrooms feels stuffy in the morning, it is often because the ventilation is insufficient. Without an adequate supply of fresh air, carbon dioxide levels increase overnight as a natural result of human respiration. Elevated carbon dioxide concentrations can make the indoor air feel stale and may cause tiredness, headaches, and reduced sleep quality.



During the day, when cooking, socialising, or using the cottage, the need for an adequate supply of fresh air becomes even more important. Musty indoor air can also leave its smell on clothing, serving as an unwelcome reminder of the cottage visit long after returning home.