Modern garages are no longer just for parking cars. They serve as storage spaces for bicycles, tools, garden equipment and seasonal items. Although well protected from theft and bad weather, there is often an invisible danger lurking here: damp.
If the humidity consistently exceeds the optimal range of 45 to 55 per cent, there is a risk of costly damage to the building structure and its contents, regardless of whether your garage is heated or not. There are various methods available to regulate the indoor climate in the long term: these range from simple everyday habits to fully automatic ventilation systems.
Moisture enters the garage in various ways, regardless of whether the garage is heated or not.
Typical sources of moisture:
If this damp is not removed, it has serious consequences:
| Hazard | Cause & Effect | Possible consequences |
|---|---|---|
| Mould | Spores find an ideal breeding ground on damp walls and spread. |
|
| Corrosion (rust) | Persistently high humidity triggers oxidation processes in metals. |
|
Before mould or rust sets in, you can minimise moisture ingress with a few simple steps.
🧹 Keep it clean: Sweep up wet leaves and dirt regularly.
❄️ Clear away snow: Clear snow off your car before driving it in.
🛠️ Maintenance: Check the roof and clean the gutters.
However, particularly during wet autumns and cold winters, these measures alone are often not enough. A well-thought-out ventilation system is required.
There are various approaches to keeping the garage dry. Each concept has its own specific advantages and disadvantages:
Most garages, particularly prefabricated garages, already have built-in ventilation slots or a garage door that does not seal completely airtight.
Traditional cross-ventilation: the garage door and the window opposite are opened fully at the same time for 5 to 10 minutes, ideally 1 to 2 times a day.
Mechanical or electric dehumidifiers actively remove and collect it in a container or absorbent material.
Smart ventilation systems or sensor-controlled drives monitor the humidity inside and outside. Ventilation only takes place when the outside air is actually drier than the air in the garage.
If you want to prevent damage to vehicles and buildings, controlled ventilation of your garage is essential. Whilst simply airing the garage thoroughly is often sufficient in summer, automatic, sensor-based ventilation solutions offer the best protection against mould and rust – particularly in winter – and are completely convenient, safe and efficient.
Ventilation prevents moisture from building up in the garage. If the relative humidity consistently exceeds 55%, this creates ideal conditions for mould and rust. By ensuring a regular exchange of air, you protect vehicles, tools and the building structure from costly consequential damage.
The ideal humidity level in the garage is between 45% and 55%. During the winter months, this figure may rise temporarily, but should be brought back down as quickly as possible by ventilating the garage effectively.
In winter, it is advisable to ventilate briefly and thoroughly by opening windows on opposite sides for 5 to 10 minutes (1 to 2 times a day). The garage door and a window on the opposite side should be opened at the same time. Windows should not be left tilted open all the time, as this will cause the walls to cool down.
Yes, absolutely. Even in unheated garages, condensation forms due to cold, wet vehicles, slush or damp air. As cold air can hold less moisture than warm air, moisture settles particularly quickly on the walls of unheated garages and on vehicle parts.
Generally speaking, no. Whilst forced ventilation (ventilation slots or leaky door seals) does ensure a basic level of passive air exchange, it is not sufficient – particularly during the damp autumn and winter months – to remove moisture that has entered the garage (e.g. from a wet car) quickly enough.
There are three key measures to prevent mould and rust: 1. Brush snow and moisture off the car before driving it into the garage. 2. Sweep out wet leaves and dirt regularly. 3. Ventilate the garage thoroughly by opening the windows, or install an automatic, sensor-controlled ventilation system.
An automatic garage ventilation system uses sensors (hygrometers) to continuously measure the humidity levels inside and outside the garage. The system only opens doors, windows or ventilation elements when the outside air is drier than the air inside the garage. In the event of rain or if the outside humidity is too high, the system remains closed automatically.
Adsorption dehumidifiers are suitable for unheated garages in winter, as traditional condensation dehumidifiers are hardly efficient at temperatures below 10 °C. In general, however, active ventilation is more sustainable and cost-effective than running an electric dehumidifier continuously.
Yes, many modern garage door operators have a built-in ventilation setting. The door moves up just a few centimetres to allow air to circulate, whilst still remaining locked and burglar-resistant.
Are you planning a new-build or refurbishment project, or do you need to design the right ventilation solution? We offer support in drawing up the ventilation concept in accordance with DIN 1946-6 and in selecting the appropriate equipment.
Support from LUNOS experts regarding DIN 1946-6 and equipment selection.
Download: Design tool for independent planning.
Phone: +49 30 362 001-0
E-mail: info@lunos.de
