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Here at American Vision Windows, we receive calls every year with customers concerned about their windows during the rainy season. We wanted to reach out early to alleviate any concerns you have before they happen.


Here are the top concerns our customers have during the rainy season:

Why is there water in the track of my new windows?
Why is moisture building up inside/outside of my windows?
Why is there Mold building up around my window and trim?
Annual window inspection checklist
Manufacturer Warranty Coverage links

Why is there water in the track of my new windows?

Are you worried that you have water leaking into your window track? Not to worry, water in the track of your windows is perfectly normal. Your windows have a drainage system built into them it is called the “weep holes”. These are strategically placed to drain water out of your window while preventing airflow into your home and may require cleaning and maintenance.

Proper Drainage System Maintenance

Weep Hole Locations:

  • Exterior bottom corner of windows
  • Inside the bottom of the screen track
  • On the inside below the window track sliding windows.

Drainage Systems:

  • It’s normal for water to accumulate in the sill or track area during rain that is driven by wind.

The water is intended to drain to the outside as water builds up and outside pressure subsides.

  • A good time to inspect and clean weep holes is when excessive rain is anticipated.
  • Keep sill and track areas clean of dirt or debris.
  • Check that both the inside and outside of the drainage or “weep holes” are always clear of dirt, stucco, sand or building materials.
  • Clear dirt and debris from the weep holes with the use a soft brush to clear openings, if necessary. Additionally, a can of compressed air can be used to clean blockages in the exterior weep holes.

Frame Cleaning:

  • Vacuum dirt from windowsill and track areas before washing.
  • Clean window and doorframes with a mixture of mild dish soap and water.
  • Always rinse completely with clean water and wipe dry.
  • Abrasive or caustic cleaners or solvents are NEVER recommended.

Glass Care:

  • Clean the window glass with mild dish soap and clean water.
  • Avoid washing glass in direct sunlight.
  • Abrasive or caustic cleaners are NEVER recommended, they could cause permanent damage to the finish/coating of the glass.
  • Never use any petroleum-based cleaners or caustic chemicals on your glass.
  • Never use a razor blade, putty knife or abrasive pad to clean the glass.
  • Never use a high-pressure spray nozzle when rinsing your windows and doors.
  • Recommended Cleaners: Sprayway Glass Cleaner Aerosol, Windex, Fantastik, Dawn dish soap/water solution

“10 tips to prepare for the rainy season” (Los Angeles Daily News): Click to view page.


How Window Weep Holes Work
How To Clean Your Sliding Windows
How to Clean Your Double-Hung Window

Why is moisture building up inside/outside of my windows?

Moisture on windows and doors is commonly referred to as condensation. Condensation on the inside of your windows or patio doors is the result of high humidity that produces droplets or fog once it hits a colder surface. While it can be concerning or frustrating, the good news is you can minimize or prevent condensation by controlling the humidity inside your home.

The first thing you should know is that condensation is NOT caused by the windows, please continue reading to learn more.

Condensation Buildup on New Windows

Why condensation builds up:

Condensation on windows is caused by humidity (or water vapor), which is present in virtually all air. Under certain conditions, window condensation can occur both inside and outside your home, but your windows are not the cause of the condensation. When the water vapor comes in contact with a surface the vapor condenses. Condensation can occur on windows during the winter if the humidity inside your home is too high.

What is exterior pane condensation?

Condensation on the outside of windows or patio doors usually occurs during spring and fall seasons typically when cool nights follow a warm day. Condensation on the exterior glass panes is a natural phenomenon, especially for energy-efficient windows/doors that restrict the airflow between the panes of glass. To combat exterior condensation, open window coverings at night to warm up exterior glass and remove/trim shrubbery near windows or doors to promote air circulation. This condensation will evaporate once the day warms.

What is interior pane condensation?

Condensation on the inside of your windows or patio doors is the result of high humidity that produces droplets or fog once it hits a colder surface. Air with high humidity holds water vapor until it comes into contact with a surface temperature less than or equal to the dew point. This is commonly seen in a foggy mirror after a hot shower, the vapor from the shower could cause condensation on your windows. Condensation usually occurs first on windows because glass surfaces have the lowest temperature of any of the interior surfaces in the home.

What causes high humidity?

All homes have a certain level of moisture due to household activities. Activities such as cooking, laundry and dish washing can add up to five pounds of water vapor into the air daily! Other moisture-producing agents include plants, heating systems and humidifiers. Humidity comes from excess water vapor (moisture) in the air. Seasonal changes, quick changes in temperature, reconstruction and remodeling can also add excess humidity temporarily into the air. During construction, large quantities of water are displaced into the air from building materials such as concrete, plaster, taping, etc. After one season of heating it will commonly dry out and your condensation problems should disappear.

How does moisture go through walls?

Water vapor is the gaseous form of water and is an invisible source of many problems in today’s buildings.

During the winter, the climate inside a home is much more humid than colder air outside. The vapor pressure, can actually force the moisture inside through cement, wood, plaster and brick. Vapor Pressure causes moisture in wet air to flow toward dry air, this flow acts independently of air currents. Some varnishes and paints block the flow of the moisture, so condensation can occur between the inside and outside walls, or under exterior paint surfaces. This can cause rot in a home’s wood frame, blistering in paint, and deterioration of other building materials.

Why wasn’t it always there?

Old drafty windows allow moisture to escape through inefficient seals and cracks. Today’s windows and doors produce a more energy efficient, “tighter” home. This is great for keeping your home quieter, cleaner, and more comfortable BUT by sealing your home you are also keeping moisture in. With this said, it is very easy to build up extremely high levels of humidity in homes today.

Here are some tips to reduce your home’s humidity:

  • Be sure all ventilation to the outside is functional.
  • Use kitchen and bathroom exhaust fans. Run exhaust fans during and after the activities have ended.
  • The process of heating your home will reduce the relative humidity-provided it is dry heat. It will counter balance most or all of the moisture produced by modern living.
  • Open the fireplace damper to allow an easier escape for moisture.
  • Open windows and doors when practical to reduce excessive moisture inside the home.
  • Open drapes and other windows coverings to allow warm air from inside to flow across windows and reduce condensation / moisture build up.
  • Use ceiling fans to keep air circulating in your home.
  • Use dehumidifiers to reduce the amount of moisture in homes with humidity problems.


Simonton brochure: “Understanding Condensation in your Home”


Understanding Exterior Window Condensation
How to Reduce Interior Condensation on Your Windows (by Anlin Windows)

Why is there Mold building up around my window and trim?

The growth of mold on window frames, sills, glass and tracks is a common problem in many of the homes built today. The presence of mold growth on window surfaces can easily be controlled through regular housekeeping and maintenance. This mold does not adversely impact air quality unless the growth is extensive and not handled properly. Read on to learn how this affects your home.

Interior Maintenance to Avoid Mold Buildup

Why condensation builds up:

Did you know?

Mold can often grow undetected inside enclosed spaces such as inside wall cavities, under bathroom and kitchen cabinets, inside HVAC systems, behind baseboards, and moldings.

It is often more of an aesthetics concern to homeowners than a public health issue. Stachybotrys, the mold spore typically referred to as “toxic mold” or “black mold” is rarely found on window surfaces, as the growth conditions on window surfaces are typically not suitable for supporting Stachybotrys growth.

Mold growth is common whenever an organic food source comes in contact with moisture for any extended period of time. In order to control mold growth, it is necessary to control either the food source or the moisture source. The following are some suggestions for controlling the food and moisture sources on window surfaces to help limit the development of mold growth.

Controlling The Food Source:

The aluminum and vinyl frames around windows and the window glass it self are not food sources for molds. When mold growth is found growing on these surfaces, it is usually feeding on organic debris such as skins cells, pollen, animal dander, dust mites, insect fragments, etc. that accumulate on these surfaces.

These particles are commonly found in indoor air and are common components of house dust. Regularly cleaning of surfaces where dust can accumulate can minimize the food source and help to control mold growth. Painting your window sills with a high gloss paint can also make cleaning easier and help to protect the wood or the organic components of the sheet rock on the window sill from coming in contact with the moisture.

Controlling the level of these organic particles in the air will also reduce the number of particles that settle on surfaces and further help to control mold growth. Using a high efficiency filter on the HVAC return and changing the filter often will help to remove more of these organic particles from the air. Vacuuming with a HEPA filter vacuum will also help to remove settled particles from carpeting and upholstered furniture items. Without a HEPA filter, the microscopic organic particles that are vacuumed can easily move through the vacuum and become airborne only to resettle later. Dusting with a damp cloth or an electrostatic cloth rather than a feather duster or dry cloth will also help to remove settled dust rather than making it airborne. Regular ventilation with outdoor air will also help to dilute the concentrated particles typically found in indoor air and further reduce the number of particles that settle.

Controlling The Moisture Source:

In most cases, the moisture near windows that allows mold to grow is due to condensation on the window glass or frames. This is becoming a more common problem in homes, which are now highly energy efficient. The same construction technology and code requirements that keep heated air or cooled air inside also traps moisture inside.

Moisture is produced from a variety of sources including bathing activities, cooking, laundering clothes, human respiration, humidifiers, or construction defects to a name a few. It is necessary to periodically open windows and use exhaust fans to regularly prevent this moisture from accumulating in the air indoors. Relative humidity is a measure of the moisture content in the air expressed as a percentage of the amount of moisture that the air is capable of holding at a particular temperature. Indoor relative humidity levels should be maintained below 50% to minimize the potential for mold growth or other indoor air quality problems.

Because warm air can hold more water than cold air, condensation occurs when warm, moist air is cooled. The temperature at which this occurs is called the dew point. The dew point is often reached at windows when warm air inside comes in contact with a cold glass or metal surface on the window. This is usually more common in the winter time and is most prevalent during the early morning hours when outside temperatures are at their lowest. Much of this condensation quickly evaporates as outside temperatures increase during the day.

Reduce The Level Of Moisture In The Air:

Reducing the level of moisture in the air will help to keep relative humidity levels low and help to prevent condensation. Moisture can be removed from the air by use of exhaust fans, opening windows and ventilating with outdoor air or through operation of a dehumidifier. Never operate humidifiers indoors, which only add moisture to the air unless you take measures to maintain or control relative humidity levels. A hygrometer, or relative humidity meter, can help to monitor humidity levels so occupants can ensure they stay within normal limits. In the winter time when buildings typically receive less ventilation with outdoor air, a hygrometer can alert occupants to when humidity levels increase to the point where it is necessary to open a window or operate an exhaust fan.

Manually Remove Standing Water On Window Surfaces:

At times it may not be possible to effectively control relative humidity levels or the level of air circulation and condensation will still occur. In these instances, it may be necessary to remove the condensation manually by wiping with a dry cloth. This is generally not the preferred method of control for occupants, but it is effective. It is not necessary to wipe up condensation on all windows every day. Most condensation that develops will evaporate naturally. It is typically on north facing windows or windows that are in shaded for longer periods where the moisture takes longer to dry. Condensation will also generally be worse on days where outdoor temperatures are lowest, and it is on these days that wiping windowsills is often necessary.

Cleaning Existing Mold Growth:

To clean existing mold growth on window surfaces, use a liquid detergent solution and a sponge or nylon brush. It is not necessary to use harsh chemicals such as chlorine or bleach, which can potentially damage metal surfaces or carpeting below the window. Liquid Detergent is just as effective at removing the accumulated dust on which the mold is feeding. Rubbing alcohol or a diluted chlorine solution can be used in small amounts as a final sterilization of the surfaces after cleaning, however, the sterilization will only be effective until new dust starts to accumulate. If there were mold growth on sheet rock windowsills, the same cleaning methods would apply. It may take longer to clean the sheet rock since the texture over the sheet rock is porous. The mold growth rarely extends below the top surface of the sheet rock sill, and it is not necessary to remove the windowsill unless the water damage and mold growth is very extensive such that the sheet rock has become soft and is not structurally sound. Continuous cleaning may damage the paint, which should be reapplied if necessary.

While controlling moisture and mold growth on window surfaces requires some regular maintenance by occupants and can be inconvenient at times, it is usually only for three or four months during the winter that these steps are necessary. Once temperatures increase outdoors, condensation becomes less of a problem.

If all the windowsills in your home are cleaned at the beginning of spring, mold growth will typically not return until the next winter. If existing mold growth is not cleaned as summer approaches the mold growth will dry and will be harder to clean later.

While mold growth on window surfaces due to condensation is not a significant problem, mold growth or water staining below windowsills could be a sign of a larger problem with water intrusion from outdoors. This can potentially lead to more serious mold growth and water damage that may not be initially visible. If mold growth or water damage is observed below the windowsills, then additional investigation work should be completed to determine the moisture source so it can be quickly resolved. It is also important to regularly inspect and maintain the condition of the caulking around the windowsill to prevent condensation from entering wall cavities where moisture takes longer to dry, which could lead to more extensive mold growth.

Annual window inspection checklist

Preparing Your Home for the Rainy Season

Rain storms are forecast to hit Southern California and the rest of the country hard. Preparing your house and windows — now — can be the best hedge against an unpredictable season. Below are tips to prepare for all of the water headed our way.

Wood Window & Door Checklist:

  1. Inspect the interior and exterior finishes around windows and doors. Is the paint or stain in good condition? Signs of flaking and peeling may mean that it’s time to refinish the unit.

  2. Look closely at all exterior surfaces for cracking deteriorated wood and other damage that might be caused by condensation or other water penetration. Are any interior surfaces such as walls, floors or ceilings discolored or showing the effects of moisture?

  3. Check windowsills and tracks for dirt and other debris such as sand, leaves, insects and pine needles. Open the windows and clean out the area with a soft brush. Do the same for sliding patio doors. Debris can hamper the airtight effectiveness and overall performance of doors and windows.

  4. Feel for uneven sliding and sticking when you open and close a window. Try using a non-oily lubricant on the opposing finishes. Paraffin wax works well and does not attract as much dust and grime.

  5. Look at the weather stripping around all doors and windows. Re-attach any loose portions and replace portions that are ripped or torn.

  6. Operate the locking mechanisms and make adjustments if they feel loose or don¹t work smoothly. Locks not only help keep out potential intruders, but they hold doors and windows tightly to lock out rain, wind, snow, and insects.

  7. Inspect any weep holes and breather holes if your windows have them. Weep holes allow excess moisture to escape and breather holes allow air exchange within certain components. Clear blocked holes with a wire, toothpick or similar device.

  8. Check all exterior sealants and caulking on and around all windows and doors. Pay particular attention to areas susceptible to punishment from rain, water and extreme sunlight. Remove damaged material and reapply sealant.

  9. In coastal locations, rinse all exterior metal components and cladding to minimize the corrosive effects of salt spray and fog damage. This should be done at least quarterly.

  10. Look for signs of air leakage around the window. Improperly installed windows or doors which permit air leakage not only decrease energy efficiency, but can allow unwanted moisture into the wall cavity.

Vinyl Window & Door Checklist:

  1. Sash/Panel Inspection (Operable Portion of window) Inspect sash or patio door panel annually (monthly for coastal areas). If the window has a removable sash, it may be helpful to remove it before inspection. Ensure the window is able to lock and secure, Inspect vinyl stiles and Rails for Damage (Cracks or Splits in Vinyl surface), Check glass for cracks, check for fogging between the panes of glass.
  1. Weather-strip Inspecting and maintaining weather-strip can help avoid costly structural damage from water leakage and energy loss due to air and/or water infiltration. Replace weather-strip that is missing, torn, cracked, brittle, discolored, gummy, or that has no ³bounce back² when pressed down. Call us for replacement instructions.
  1. Weep System Vinyl windows and patio doors are not subject to moisture damage; however, damage could develop in the structure around the unit if water does not drain properly from the sill area to the exterior. Interior weep holes are usually a rectangular or round hole cut in the vinyl in the bottom of the sill track or in the face of a vertical member of the sill near the bottom. Weep holes may be covered by a sill insert or roller track. Access to these weep holes may require removal of the sash or panel and then removal of the snapped in sill insert or roller track. Exterior weep holes are usually around or rectangular hole cut in the exterior face of the vinyl sill. These may have a small flap or baffle covering the hole.
  1. Exterior Sealant Joint A proper Seal of the joint between the window and the exterior surface of the structure will keep water and/or ari from leaking into the house. Inspect the sealant joint for Cracks, Voids, Deteriorating areas ( Loss of Adhesion). When repairing a sealant joint, 100% silicone sealant is the most durable but is not paintable, if painting is required is 100% polyurethane sealant.
  1. Screens Inspect screen for tears and remove and ensure a tight fit on all four sides, Screen door rollers can be sprayed with Silicon spray if running rough, Clean tracks prior with vacuum. Removing and placing on a hard surface can clean screen. Gently spray with water and brush lightly with a soft bristle brush. Screen related services are not usually under warranty.

Annual Window Care & Maintenance Links:

Preparing Your Home for the Rainy Season (Articles)

Manufacturer Warranty Coverage Links

Anlin Windows and Doors: Current Warranty information.

Milgard Windows and Doors: Current Warranty information.

Plygem Windows: Current Warranty information.

Great Lakes Windows: Current Warranty information.

Lincoln Windows & Doors: Current Warranty information.

JT Windows and Doors: Current Warranty information.

Have more questions?

If you would like to schedule a service call, or if you have any other questions please feel free to email our service team at: Or call us at (888) 920-7222 today. We’re here to help you!

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