This information will review some of the causes of condensation and some helpful hints to relieve the situation. Please keep in mind that windows and patio doors are not the cause of the problem, rather they are an indicator of a greater problem.
Condensation is the fog that is evident on the glass of your windows. This is the same fog that appears on the outside of a cold glass during the summer.
Condensation is actually the result of high humidity levels in your home. It generally appears as moisture or ice on the interior of the glass. The problem is more visible on the glass of your windows because the surface condenses more easily. This means that the glass has the lowest temperature of any visible surface in your home. It needs to be noted that if moisture is visible here, it could be happening elsewhere as well. Problems such as peeling paint, rotting wood, mildew or moisture spots are typical symptoms of condensation.
The cause of the condensation is too much moisture in the air in relation to the temperature of the surface on which the moisture condenses. When warm air meets a cooler surface, it condenses. This creates the visible moisture you see on the surface of your windows which is similar to your cool glass windshield of your car. Condensation also occurs when the flow of warm air is restricted from reaching window surfaces causing the warm moist air to cool and loose its ability to retain higher moisture levels.
Humidity is the amount of moisture in the air. It may come from various sources. Your home needs a certain amount of moisture, but deciding how much you need is a critical decision.
The following recommended humidity levels will help you with the moisture level of your home; reducing humidity while maintaining comfort. It is based on the inside relative humidity for a 70° indoor temperature. It is also important to note that for each degree cooler than 70° the interior relative humidity should be reduced an extra 2%-4%.
If there is moisture on your windows, it is important to check your entire home. Problem areas could reveal themselves as damp spots on ceilings and walls. The end result could be the moisture passing through the walls, insulation, and to the exterior walls causing peeling or blistering paint or other damage anywhere there is a vapor barrier. This could eventually cause rotting of the frame of the building if left untreated.
Causes of Humidity
As stated before, moisture may come from a variety of sources. The following is a list of average daily living activities and how much moisture a family of four contributes to their living environment, which can add up to more than 18 gallons of water per week.
A New Home
When a new home is built, a great deal of moisture is released from the building materials such as wood or plaster. Since newer homes are manufactured more air-tight, there is typically no outlet for the humidity to escape unless steps are taken to vent the moisture during construction and the first few heating and cooling cycles. During the winter months in cooler climates, the moisture will be released into your home. This circumstance usually occurs only during the initial heating season.
Location and Time
Some regions are more prevalent to condensation than others. Generally areas that reach 35° Fahrenheit or below in the winter months are more susceptible to condensation.
Interior condensation is more likely in the initial heating months of winter or during a severe, rapid change in temperature over a short period of time during the winter. This happens when moisture in the air contacts a surface whose temperature is lower than the dew point (the temperature in which air manufactures dew). This symptom should gradually dissipate during the season.
Exterior surface condensation usually occurs on sultry, humid summer days, typically when an air conditioner is being used. This creates a surface temperature on the glass below the dew point.
Humidity within a home will fluctuate at different times of the day as well. Generally the highest humidity readings occur at night or in the morning when the occupants are conducting the daily activities that cause humidity levels to rise such as bathing, cooking and laundry.
Type of Window
Some window types, such as bays and bows, are more subject to condensate. Because they are more exposed to the environment, these windows may be somewhat cooler. Also, due to their shape, there is a lack of air movement within the window.
One solution to this problem is to make sure that the window is properly insulated upon installation. Contact your contractor or insulation specialist for further details. Another solution is to use a fan to promote air circulation.
Another concern might be the type of window coverings that are being used. Those that are close to the windows restrict the flow of warmer air and can contribute to a condensation problem.
There are several steps that you can take to reduce your indoor humidity level. The most important one is to make sure your home is properly vented.
Install vents in all areas such as attics and crawl spaces and make sure they are always unblocked. Many people cover attic vents or louvers for the winter thinking that they are keeping cold air out, not realizing that they are also keeping moisture in.
Install exhaust fans in rooms with high humidity levels such as bathrooms and kitchens. Make sure they are used during and long after taking a bath/shower and cooking. Also make sure that exhaust fans and appliances, such as clothes’ dryers and gas heaters, are properly ducted, sealed and vented to the exterior of the home, not into a crawl space or attic. Gas appliances should be a major concern. Water vapor is one of the by-products of gas combustion.
Lincoln highly recommends the use of an air exchanger. Combined with the use of ceiling fans and dehumidifiers, condensation can be drastically reduced. A temporary solution for severe cases would be to open a window in each effected room for a short period of time.
For more specifics on these and other ideas, we recommend consulting a heating and ventilation specialist.
New Construction Homes
When planning your new home, here are some helpful suggestions that should be considered in addition to those mentioned for existing homes:
Choose a wood window instead of a metal one. Wood is a much better insulator than metal. Also, make sure your windows and doors are Energy Star™ certified. Make sure that your contractor has considered the most appropriate way to keep soil moisture from permeating the basement or foundation. Proper insulation is one of the most valuable tools in any energy efficient residence. But many people often forget their water pipes and cold air ducts. Any pipes (such as cold water pipes) or ducts that condensate in the warmer months should be covered with insulation that has an exterior vapor barrier.