Moisture Management for Building Tiny
Managing humidity and moisture in a small space is an important consideration when designing your heating and ventilation system. Humidity from cooking, showering, and breathing tends to build up quickly in a small space if it's not well-ventilated. A typical family can add gallons of moisture to the air throughout the day.
In a tiny space, humidity buildup can be a much bigger problem than in traditional construction. Since the interior volume of a typical Tiny House, school bus conversion, or RV is so small, humidity levels can rise quickly. During the Winter, humidity condenses on cold walls and windows, which can cause mold to form.
How Heaters Affect Humidity
Some heating systems, like unvented propane heaters, add moisture to the air as they heat. On a cold day, a catalytic heater can pump gallons of water into your air.
Other heating systems, like propane furnaces, don't add additional moisture to your air, but don't remove it either. Unless your furnace is powerful enough to make up for a cracked vent (or if you have a heat recovery ventilator installed), humidity will continue to build up in your living space and condense on your windows and walls.
A powerful dry heater like a wood stove can be used not only to heat your space, but to dehumidify it. Since all of the combustion products of wood burning go up the chimney, a wood stove adds zero humidity to your space. Further, since a wood stove is such a powerful heater, it can be used to dehumidify your space.
Using a Wood Stove as a Dehumidifier
While an electric dehumidifier works fine, your wood stove can serve as a dehumidifier on the cold days when it's needed most.
If you notice some condensation forming on your windows, throw an extra log on the fire to produce a bit of extra heat, and then crack a roof vent or a window near the ceiling just enough to allow a small amount of air to escape. The extra heat rising from your space will carry the moisture in the room along with it, and your wood stove will keep your space comfortably warm.