Window Condensation & Moisture

What Causes Window Condensation & Moisture?

People often call our shop with questions about window condensation. These inquiries vary widely so I decided to include this topic in my “Nuts & Bolts” vinyl windows series. Let’s first explore what causes window condensation. Anyone who’s had single pane windows knows that when the temperature drops their windows collect interior moisture. It often resembles a waterfall of unwanted water vapor in their home. This occurs because as the temperature plummets your furnace turns on pumping out warm, moist air. When this air hits your chilled window, condensation forms. There are other reasons why moisture can form inside your window so we’ll explore all of these scenarios.

What is Multi-Pane Glass & How Does it Stop Window Condensation?

For many centuries windows were comprised of a single pane of glass. Unfortunately, glass is not a particularly good insulator against heat or cold. However, when combined in multiple panes it becomes much more efficient and reduces condensation. Thus, a door or window containing dual or triple glass panes is often called insulated. The concept of insulated glass technology began in the mid 1940’s and revolutionized residential windows. Over time, we’ve also learned that adding dense, inert gas into the encapsulated space between panes further boosts window efficiency. This is why argon gas is used in multi-pane windows.

Why are Seals So Important to Multi-Pane Glass Technology?

Multiple glass panes are sealed together using special technology so that they’re airtight, or hermetic. The part that joins and seals them is called a spacer. Over the last 20 years or so spacer technology has made tremendous gains in reliability and efficiency. However, as with most technologies there are differences in quality between spacer types. This is important as the long-term insulating effectiveness of the spacer is directly tied to its quality level and how it was applied. Not surprisingly, mass produced builder-grade windows use very inexpensive spacer technology with a quick and easy application process. They’re also usually made with little regard for post-testing and quality control. By contrast, higher quality windows tend to have superior spacer technology and are manufactured in a computer-controlled environment. In addition, multiple testing criteria and a much higher level of quality control is applied to their production. Finally, very few people including window sales people know much about this part of window technology!

Can Failed Seals Allow Condensation Between Window Panes?

The main reason multi-pane windows exhibit condensation is due to seal failure. When this happens moisture penetrates the sealed space becoming visible over time. Unfortunately, it’s not easy to physically see seal breaks because they’re usually micro-sized defects. Therefore, the only way to know that one has failed is to visibly see moisture inside the glass unit. In most cases, failed seals simply produce a foggy look that you can never clean. With moderate failures moisture will be visible and trapped inside the space between the panes. However, in extreme cases calcium crystals will begin to form resembling a science project that looks milky white. When you buy Ringer Windows seal failure is covered in the warrantee so the glass will be replaced. I’m proud to say that in nearly 10 years we’ve had NO seal failures. This is because we only use Cardinal Insulated Glass with patented stainless steel XL Edge Spacer technology. If you’d like to learn more about it please visit their site at cardinalcorp.com. One last thing. I discussed single pane windows earlier but wanted to restate that you shouldn’t expect much performance or efficiency from them!

What Else Causes Condensation In an Insulated Window?

Condensation can also occur on the inside of an insulated window for a more benign reason. It sometimes happens when interior humidity levels are very high as in a bathroom with a steamy hot shower. However, after the extra moist air is evacuated the windows will dry out and quickly return to normal.

Which Do I Need in Texas, Double or Triple-Pane Windows?

Over the last decade or so, we’ve seen a surge of triple pane glass usage. Generally speaking, triple pane technology only makes sense in very cold climates. It’s also more expensive and extra work to produce with a generally higher failure rate than dual pane glass. We know this because we’ve run tests on dual and triple pane glass for our region (central Texas). The fact is, it doesn’t get cold enough to make a difference in efficiency with triple pane windows. If I were a consumer, it would make sense to me that more glass panes would make a better window. However, that’s simply not true in all cases. Lastly, because Texas is mostly hot with mild winters, triple panes would add to window cost without providing benefits.

Can Moisture Also Collect on the Outside of My Windows?

Some folks call us with concerns about moisture on their window exteriors, particularly on heavy dew mornings. Insulated glass and replacement windows do not stop this type of condensation from occurring. However, please know that it is completely normal and O.K. As soon as the humidity level drops or the sun comes out the moisture will burn off and go away. But after a few cycles of heavy dew windows may become dirty from atmospheric residue and dust in the air column. Unfortunately, there’s nothing anyone can do to prevent exterior condensation.

A True Story About Window Condensation

I’d like to share a true story about condensation and our windows. It wasn’t funny at the time but after we discovered the root cause even the homeowner got a chuckle from it. It was December and we’d just finished installing our double-pane windows in a client’s home. About two weeks later the first really cold snap hit like a ton of bricks. Temperatures plummeted from the mid 50’s to the low 30’s in a matter of hours. Naturally, our client turned on his gas heater to warm his home. However, after a few hours he noticed water on all the interior sides of his new Ringer Windows! Everyone was puzzled, baffled, and shocked! This had never happened before! So, we dug through all of our technical manuals and looked at every possibility. After a day or so, the homeowner informed us that his wife just had their carpets steam cleaned without his knowledge. As a result, when his heater came on the moist carpet warmed up creating artificially high humidity levels in his home. The carpets dried after a few days and the interior window condensation stopped and never returned.

If anyone has questions about condensation or ANYTHING about windows, please call our shop and ask for me directly!

Contact Us About Our High-Quality Vinyl Windows Today!

Submit a contact form or call 512-989-7000 today about our high-quality vinyl windows. We’ll visit with you and provide a FREE estimate! Ringer Windows is the local only window manufacturing company in central Texas. Our experts are ready to assist with your vinyl new construction or replacement window needs. Also, be sure to ask about our full-service window installation. You’re just a local phone call away with Ringer Windows!