CONDENSATION

Wet Windows
Water running down windows, mildew growth on wall and ceiling are probably the most common moisture-realted problems that affects houses - CONDENSATION.

Relative Humidity
Air always contains a certain amount of moisture in the form of water vapor. However, there is a limit to the amount it can carry, according to its temperature. The warmer air, the more moisture it can hold. When it can hold no more it is said to have reached saturation point (100% realtive humidity).

The rate of mosisture production and the rate of its removal establishes the resulting levels of humidity in a house. Moisture can be added intentionally to room air through the use of humidifiers or unintentionally through normal living activities.

Adding Moisture
A typical house of 1500 square feet at 70 degree F is holding about 3/4 gallon of water when the himidity is 40%. Adding 1 galloon brings the humidty to about 100% and condensation is bound to occur on cool surface. A family of four releases 1.5 galloon of water into the air every day just by breathing. A humidifier typically releases 1/4 galloon of moisture per hour.

If moisture is generated faster than it can be removed, the realative humidity will rise until condensation occurs. Because of their lower surface temperature, windows are usually the first surfaces on which condensation is noticed. For that reason they are often used as an indicator of excessive humidity.

Mold
The mildew and mold smell foul, and the huge concentration of spores in the air trigger allergic reactions. In severe cases, condensation occurs within walls, attic, causes structural decay.

Picture: Mildew formed at exterior walls/ceiling due to excessive moisture in the house

Control Moisture
In order to control mildew and indoor quality, you can either lower the interior humidity level or warm up the surfaces on which the moisture condenses. Since the latter is often impractical, it is usually best or easiest to lower the humidity level.

Reducing the humidity level can be accomplished by reducing the rate of moisture generation and by increasing the rate of moisture removal (ventilation system).

Increasing the temperature of the cold surface can be accomplished by adding thermal insulation and/or by increasing air circulation.

Most houses experience some degree of condensation, but only a relatively small percentage will develop serious problems because of it.

HUMIDIFIER

Most central humidifier are relatively inexpensive pieces of equipment added to forced-air furnaces. Their purpose is to raise the humidity levels within the house during the heating season.

Location
Humidifier should be mounted on the return air ductwork with a bypass duct to the supply plenum. Where central air conditioning is found, a humidifier duct damper should be present. This damper should be kept closed during the cooling season to prevent air conditioner coil ice-up.

Common Problems
Drum type humidifiers are perhaps the most common type. They have several common problems. The water level often requires adjustment. Without proper adjustment, the tray overflows which can cause damage to the furnace. The tray sometimes overflows because mineral deposits foul the automatic water supply valve, causing it to stay open, even when the tray is full. The water supply connection to the supply plumbing pipe is a common leakage point.

Maintenance
Humidifier requires cleaning monthly or even weekly during the heating season. It is not uncommon to find units that are caked with minerals and salts clogging the tray and the float, and spinners that are loaded with solids and can just barely turn. There is enormous potential for mold spores, allergens, and germs-which thrive in the stagnant water pool -- to be circulated directly with the air in the home.

It is very important to take good care of your humidifier to avoid water overflowing, disease,illnes and condensation. If you donot have the time to look after it, remove the unit and seal all openings.

NEW HOMES AND CONDENSATION

New homes today are constructed tighter with better sealing to create less air leakage than the homes we grew up in. Therefore, new homeowners paly a more active role in ensuring their home's air quality is healthy and safe.

Builders are rquired by the Ontario Building code to install a ventilation system to pretect your new home against moisture damage and to provide you with fresh air during the heating season.

New homeowners should take time and acquaint themselves with thier ventilation system. This is the first important steop to controlling indoor air quality and protecting your new home and its warranty. Problems arising from homeowner neglest are not covered by the Ontario New Home Warranty Program.

Ventilation fans take air to the outside. The circulation fan, which is usually the furnace fan, distributes the air inside the home.

Many construction materials, especially poured concrete and wood, contain moisture and release them into the air. You will probably need to run the ventilation and circulation fans continuously during the first year whenever the windows are closed.

After the first year, the need for ventilation will depend on your family's lifestyle and the number of people and pets in your household. How much moisture is generated in the home from activities like cooking and washing.

An indication of the humidity level in a home is reflected on the windows. Some condensation of moisture on windows is common in the winter. However, excessive condensation can be a serious problem and result in expensive damage. If corrective measures are not taken at an early stage, staining, rotting and mold can result. If there is a build-up of moisture on the windows, you need to run your fans more often. If your nose and throat are constantly dry, turn the fans down or run them for shorter periods.