Keep your home's moisture at low levels, especially in the winter; controlling moisture is critical to keep indoor air healthy and to reduce energy consumption; or to prevent damage to the walls, floors and ceilings.
home Indoor moisture
Showering, dishwashing, cooking and laundry are important sources of moisture; do not underestimate them. Be aware to excess indoor moisture.
Moisture and home energy performance
Moisture is not just a source of damage in walls, attics, ceiling and floors; or a problem of poor air quality and health hazards.
Moisture also increases the energy consumption: your heating and cooling equipment will have to work harder to heat or to cool your house and to remove excess moisture.
Clothes dryers should be vented to the outside and you should have high-quality exhaust ventilation fans in each kitchen and bathroom; or a whole-house ventilation system.
When indoor water vapor circulates around the rooms and comes into contact with the glass of your windows, or with the cold surface of ceilings and walls, as it cools it condenses before our very eyes; but it can also move into the attic or into the walls and floors, causing other more serious problems.
And that's why it's so important to fix excess indoor moisture.
Mechanisms through which moisture can move into our homes and its envelope
»» Liquid water can leak into the walls through their siding, when they become saturated with rainstorm, or up from the foundations, or down from roof leaks…
»» Liquid water can flow downwards through openings, or wick through solid materials in several directions (capillarity action).
»» Water can seep horizontally, or travel up through the ground, before wicking through the structure of your house...
»» Water vapor is carried by moving indoor and outdoor air; and it can travel into the building cavities, where it condenses in contact with a cool surface.
»» Water vapor moves through porous materials (concrete, wood, drywall) by a process named vapor diffusion, or through air leaks.
Fixing Simple Indoor moisture problems
Ventilation can help minimize some simple moisture problems. See: Moisture control through air circulation.
Controlling high humidity levels
It may be a good idea to monitor humidity levels in your home by using a hygrometer and by looking for signs of condensation.
|Recommended Home Humidity Levels in Winter, for very low temperatures|
|Outside air temperature|
|Inside temp.||-15ºF/-26ºC||-7º F/-21ºC||0ºF/-17ºC||+7º/-14ºC||15ºF/-9ºC||25ºF/-4ºC|
In the winter, in cold weather, keep inside humidity at 45%-50% or lower; see table above, with recommended levels (for low outside temperatures).
In the summer, the humidity levels are not so important; but as moisture interferes with comfort, you should keep them in 45-60% range.
Dehumidifiers and air conditioners with a good humidity removal coefficient are an important way of controlling indoor moisture during summer months. But it may also be advantageous to run them for short periods during the winter, whenever there is excess moisture.