How To Get Rid Of Mold In Double Pane Windows

Finding mold on or inside your double pane windows can be frustrating. You clean your home regularly, yet those dark spots seem to show up anyway. 

In some cases, the mold is easy to remove. 

In others, it points to a bigger issue hiding inside the window itself.

Mold in double pane windows is usually caused by moisture, and once you identify where the mold is growing, you’ll have a much better idea of how to fix it.

In this post, we’ll show you how to get rid of it, and what you can do to keep it from coming back.

If The Mold Is On The Interior Glass Surface

If the mold is growing on the side of the glass that faces your room, you’re dealing with the simplest situation. 

This type of mold develops when condensation collects on the window and stays there long enough for mold spores to grow.

You can use any of these to clean the mold:

• White vinegar
• A commercial mold cleaner
• A mixture of water and mild dish soap

Spray the cleaner onto a microfiber cloth rather than directly onto the glass. Then wipe the mold away carefully. Once the area is clean, dry the window. 

While you’re cleaning, take a moment to inspect the surrounding frame and window sill. Mold often spreads beyond the glass itself, especially if moisture has been present for a while.

If the mold comes back repeatedly, there may be an indoor humidity issue that needs attention.

Also Check Out Our: Window Glass Services in Richmond 

If The Mold Is Between The Panes

Things get a little more complicated when mold appears between the panes of glass.

Double pane windows contain two pieces of glass separated by a sealed air space. This seal helps improve energy efficiency and insulation. When that seal fails, outside air and moisture can enter the space between the panes.

Once moisture becomes trapped inside, mold can begin growing where you can’t reach it.

Unfortunately, cleaning products, paper towels, and household tools won’t solve this problem because the mold is sealed inside the glass unit. 

You can’t simply wipe it away from either side of the window.

At that point, you’ll need to consider one of these options:

#1 Replace The Insulated Glass Unit

In many situations, replacing the insulated glass unit (IGU) is the most practical solution.

The insulated glass unit includes the two panes of glass and the sealed space between them. The existing frame remains in place while the glass assembly gets replaced.

This option is often less expensive than replacing the entire window, especially if the frame is still in good condition.

A new insulated glass unit restores the window’s appearance and energy efficiency while eliminating the trapped mold and moisture problem.

For many homeowners, this strikes the right balance between cost and long-term results.

#2 Consider Professional Defogging Services

Some companies offer window defogging services.

This process typically involves creating small openings in the glass unit, removing moisture, cleaning the interior surfaces, and reducing the foggy appearance.

Defogging can improve visibility and may cost less than replacing the glass. 

However, it’s important to understand that results can vary. Since the original factory seal has already failed, the window may still be vulnerable to future moisture problems.

For homeowners looking for a lower-cost temporary solution, defogging may be worth exploring. 

For a more permanent fix, glass replacement is often the better option.

#3 Replace The Entire Window

Sometimes replacing the entire window is the best way to get rid of mold in double pane windows. It makes the most sense.

Also Read: Window Repair Vs Replacement

This is especially true if:

• The frame is damaged or rotting.
• Multiple seals have failed.
• The window is older and inefficient.
• Water damage extends beyond the glass.

A full window replacement costs more upfront, but it can improve energy efficiency, appearance, and overall home comfort.

If you’re already planning other home upgrades, replacing an aging window may be a worthwhile investment.

Signs Your Double Pane Window Seal Has Failed

Mold between the panes is one of the biggest warning signs of seal failure, but it’s not the only one. Here are some common clues that moisture has entered the insulated glass unit:

• Persistent fogging between the panes.
• Water droplets trapped inside the glass.
• Cloudy glass that never clears up.
• Visible mold or mildew inside the window.
• Higher heating and cooling costs due to lost insulation.

A failed seal doesn’t always require immediate replacement, but it rarely fixes itself. 

Once moisture gets inside the unit, the problem generally continues to worsen over time.

What Causes Mold In Double Pane Windows?

Mold needs two basic things to grow: moisture and organic material. While glass itself doesn’t feed mold, dust, pollen, and other particles can collect on surfaces and provide a food source.

A few things contribute to mold growth in double pane windows.

High indoor humidity is one of the biggest causes. 

Also Read: Can You Paint Shower Door Frames?

Bathrooms, kitchens, laundry rooms, and poorly ventilated spaces often produce enough moisture to create condensation on windows.

Seal failure is another major factor. 

Once the insulated glass seal breaks, moisture can enter the space between the panes and become trapped.

Poor ventilation can also contribute. Air that doesn’t circulate well tends to hold moisture longer, increasing the chance of condensation.

In some homes, leaking roofs, damaged siding, or window flashing issues allow water to infiltrate around the window frame. Over time, that moisture can encourage mold growth around the glass, frame, or sill.

The longer moisture remains present, the greater the chance mold will develop.

How To Prevent Mold From Coming Back

Keeping moisture under control is the most effective way to stop future growth.

Start by monitoring indoor humidity levels. Many experts recommend keeping humidity below 50 percent. A simple hygrometer can help track conditions inside your home.

You can also reduce moisture by running exhaust fans during showers and while cooking. In humid climates, a dehumidifier may make a noticeable difference.

Here are a few tips:

• Dry condensation from windows when you notice it.
• Use exhaust fans consistently.
• Maintain indoor humidity at healthy levels.
• Repair leaks quickly.
• Inspect windows periodically for signs of seal failure.

Preventing moisture buildup is much easier than dealing with mold removal in double pane windows, and window replacement later.

Bottom Line

Getting rid of mold in double pane windows depends largely on where the mold is located. 

If it’s growing on the interior glass surface, thorough cleaning and moisture control may solve the problem. If the mold is trapped between the panes, the window seal has likely failed and cleaning alone won’t fix it.

In those situations, replacing the insulated glass unit, exploring professional defogging services, or replacing the entire window are usually the best options. 

FAQs

Is Mold Between Window Panes Dangerous?

Mold between window panes is usually not as concerning as mold growing openly inside your living space because it’s trapped within the sealed glass unit. 

However, it often indicates that the window seal has failed and moisture is getting inside. Plus, the underlying moisture problem can worsen over time.

Is It Worth Repairing A Double Pane Window With Mold Inside?

No, attempting to clean the mold by drilling holes or using DIY drying kits is a temporary band-aid that won’t fix the underlying issue. 

Once mold sets in, the insulated glass unit seal is permanently broken and its energy efficiency is entirely gone.