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The Common Causes of Window Seal Failure

Insulated windows are equipped with sealed double-pane glass. Sometimes, the seals could fail, resulting in reduced energy efficiency. Here’s a look at the causes of window seal failure.

How Do Window Seals Work?

Traditional single-pane glass has always been problematic because the largest component, glass, is highly conductive. It allows precious indoor heat to escape during cold days. It also lets heat seep into the house during warm days. Windows with single-pane glass increase indoor heating and cooling requirements, which result in higher monthly energy costs.

Insulated windows, on the other hand, feature double-pane glass: two glass panes, separated by an insulated spacer, are assembled so there’s a sealed vacuum inside. With no molecules to conduct heat, double-pane glass helps maintain consistent indoor temperatures, reducing the need for the HVAC system to compensate. It has proven to be so effective that all Renewal by Andersen® replacement windows are equipped with double-pane High Performance™ Low-E4® glass packages. 

Common Causes of Window Seal Failure

Even the best window seals can fail due to one or more causes:

  1. Age — Window seal technology has taken leaps and bounds over the years. Newer windows are far less likely to fail due to age. We at Renewal by Andersen are confident of the seals we use on our replacement windows that our limited warranties include a 20-year coverage for the glass packages.

  2. The Elements — Window seals can be jarred loose or damaged by wind and driven rain. Lack of protection from ultraviolet (UV) rays can deteriorate the window seal. Fortunately, it can be repaired. The earlier you notice the damage, the less repair work will be needed.

  3. Mold — Mold growing on the windows can weaken the seal and cause discoloration. A mildly acidic cleaning solution, such as diluted white vinegar, can be an effective way to remove mold. If your windows came with factory-applied coatings, read the care and maintenance manual if vinegar will affect the paint coatings.

  4. Lack of Maintenance — More than a few homeowners confuse “low maintenance” with “no maintenance”. Windows still need to be cleaned and maintained; it’s just easier when you have low-maintenance windows. This means you will need to stick to a regular cleaning and inspection routine as prescribed by your contractor.

Renewal by Andersen of St. Louis is your leading provider of replacement windows and patio doors. Give us a call at (314) 332-2364, or fill out our contact form. We serve customers in Chesterfield, MO, and nearby areas.

Reviews

"Have nothing but great things to say about the window installation done today by John Hutchinson with Renewal by Andersen! He was friendly, personable and professional and did a great job installing. He did a great job of putting down roller pads and tarps with next to zero clean up. Would highly recommend them for any window replacement needed!"

Mark V.
Jun 26, 2025

"We had our new Renewal by Andersen windows installed on June 5th & 6th, 2025 and we LOVE them! The quality, beauty, and functionality are best-in-class! The whole experience from dinner presentation at Lazy River Grill, the initial in-home sales consultation and measurement, the regular communications from the salesman and concierge, and the installation team’s professionalism and skills made the process so seamless. This is the second home we have opted for Renewal windows and doors and have been delighted both times! Thank you Renewal by Andersen STL! "

Jeff C.
Jun 7, 2025

"I had an excellent experience with RbA STL. Our designer, Courtney, was great and the finished product is awesome. The installation was easy and the gentlemen left our home cleaner than they found it upon entering. I would recommend RbA STL - you’ll get tired from their constant contacts, and that’s a GOOD thing!"

Jeramy D
Jun 3, 2025

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