basics on indoor air humidity

Humidity affects our comfort and health, the structures of our homes and their furniture. Their causes are very diverse, as are their management: ventilation, evaporative cooling, air conditioning...

Humidity and Comfort

Our perception of comfort is highly determined by humidity (or more precisely, relative humidity or, for short, RH). Even if current temperatures are normal, without a proper relative humidity we will feel very uncomfortable.

Most people feel comfortable at a relative humidity (RH) between 40% and 80%, but the ideal levels of RH are around 35-45%.

How to track indoor humidity

To track humidity you may acquire a hygrometer (or humidity meter, or moisture meter). Hygrometers are very inexpensive instruments ($10-$50) sold at many hardware stores.

Humidity effects

Low indoor humidity (below 30%) causes dry-air problems: static electricity, skin irritation, respiratory problems, cracks in drywall, etc. High humidity levels in our homes (more than 60%) are a cause of discomfort, moisture, bacteria, viruses, fungi, mites, or pathogens responsible for asthma. High humidity is also a cause of damages in residential structures, floors, ceilings, walls and furniture.

Moisture causes

Besides weather and climate conditions, moisture can also be favored by elements like...

- bad drainage involving the roof, overhangs and grounds around the building;
- insufficient insulation and ventilation;
- poor control of rain and snow, construction wet materials…;
- cooking, bathing and laundry.

See, for more information:Controlling Excess of Humidity.

Humidity management for several climate conditions

Obviously, relative humidity can be largely associated with climate conditions and weather seasons. This humidity should be managed trough...

- ventilation;
- air conditioning or...
- evaporative cooling...

In dry climates, cooling solutions use evaporative cooling and ventilation. In wet climates, air conditioning is often the more adequate solution. In other climate conditions, solutions rely upon ventilation and air conditioning.

The use of dehumidifiers and humidifiers

Dehumidifiers (or humidifiers) are important elements to balance humidity. They do not solve structural sources of home moisture, and there are other more efficient ways of dealing with humidity determined by climate and weather conditions, but they supplement or solve some situations.

See:

Evaporative Cooling
Moisture and Mechanical Ventilation