House Energy Site

Home mOISTURE Control

Moisture is responsible for many serious problems and damage in walls, floors and attics, and for higher energy bills and health hazards.

Excess moisture also increases energy consumption. Your heating and cooling system will have to work harder and to use more energy to deal with moisture.

Indoor sources of moisture

There are various mechanisms through which liquid water, humid air and water vapor can penetrate the walls, attics, roofs and floors.

But indoor sources of moisture are also relevant.

Indoor Moisture Sources and Control

Horror Stories About Moisture in Airtight Homes

That's common to hear horror stories about damages caused by moisture trapped inside walls and ceilings. And some of the stories are often wrongly associated with airtightness, in modern energy-efficient homes.

Air tight homes, leaky homes and energy efficiency
Air Sealing: Solving Moisture Problems
Passive Houses Energy Performance

GuttersDrainage Systems: The First Line of Defense Against Excess Moisture

A well designed drainage system is a very effective way of directing rainwater away from the foundation, and one of the most effective means of preventing moisture in basements and crawlspaces.

Anyway, surface drainage is seldom sufficient in rainy climates; under-ground drainage systems are also critical.

See: Home Drainage Foundation Systems

Moisture in wall surfacesWall Moisture Problems Can't Be Solved With Ventilation

Walls should be kept dry, which isn’t easy to achieve.

There are various mechanisms through which humid air, rain and snow water and water vapor can penetrate the exterior walls.

See: Wall Moisture

CrawlspacesMany Serious Moisture Problems Come From Crawlspaces and Basements

Many brand new homes have foundation moisture problems.

Basement Guide
Basement and Foundation Moisture

Attic Moisture May Come From Indoors or Outdoors

Attics are prone to moisture issues, often associated to roof leaks.

Inadequate levels of attic ventilation, ill-designed attic venting systems and leaks in the attic floor can also be a cause of moisture.

Moisture in Attics
Attic Fans Performance
Attic Electric vs. Solar Fans

VentilationVentilation Can Solve Small Moisture Problems; But Just That

Air circulation is a way of controlling mould and condensation in closets, or in unused rooms.

Anyway, most moisture problems have to be solved by acting at roof leaks, plumbing leaks, cracks and holes in walls or problems with the foundation drainage and excess indoor moisture.

Moisture Control & Ventilation
Mechanical Ventilation Guide
Ventilation for Cooling Guide

Moisture problemsMoisture Damages and Health Hazards

Wet homes are not durable or healthy.

Excess moisture is not just a cause of odors and damages in walls, attics and floors. Excess moisture is also a cause of mold and mildew, fungus and contaminants, responsible for health problems such as asthma or allergies.

Controlling moisture levels should be a priority.

Bath FanExhaust Ventilation for Indoor Moisture Removal

Cooking, showering, clothes washing and dishwashing are important sources of indoor moisture that must be properly addressed.

Every home should have exhaust fans in the kitchen and in each bathroom, ducted to the outdoors.

See: Simple Exhaust Kitchen and Bathroom Ventilation

Windows clipMoisture in Windows

Condensation on windows occurs when moist air comes into contact with the cool surfaces of the glass; windows are often the coldest surfaces in the house. But this doesn't mean that the windows are at the source of the problem.

Moisture & Windows


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House-Energy Video on Moisture Issues:




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