When asked why old window glass looks particularly wavy, many people will say that it is simply a result of the age of the glass. In other words, they believe that its waviness occurs and develops with time and is not caused by any other factor.

In fact, this particular wavy aspect of the glass in mirrors and windows is mostly found in homes built before the turn of the last century. Back at the time, houses had a very distinct characterization that today's homeowners are not completely able to understand: a blurred appearance that can distort the images behind.

Take this tree for example. Although we can actually see it is a tree, we are not able to see and examine the details of its branches and leaves which we normally could do if the window was not affected by this wavy aspect that we're trying to explain.

Old Wavy Glass
Credit: Ian Page-Echols, via Flickr

The view of a tree through old wavy window glass.

So, what is the convenient explanation? Well, to answer this question, let us take a step back and learn about the origins of the old types of glass and how they have been made. 

According to Old House Journal, the two most common styles during the 19th century were crown and cylinder glass. Both of these styles was created by involving the process of glass blowing.

It appears that, by using these techniques, it was impossible to set up a smooth, uniform look of the glass. The production process also included a heating phase where it would be put into high degrees of temperature, and a spinning phase where the glass would be repetitive put to spinning. Both phases of production largely contributed to the waviness of the matter giving it a rippled, slumped appearance.

Although techniques for glass production have improved with the beginning of the 20th century, it is important to weigh the benefits of having unique, wavy glass in your home before replacing it with more modern windows.

There is a certain charm about wavy glass that gives your home an antique, historical value that many homeowners find glamorous and appealing. Many buyers will value and appreciate the authenticity and originality of the wavy windows, and mirrors as contributing elements to the overall style of the house.

Although many prospective clients are very likely to accept the style of the 19th-century glass, they may as well refuse it, not valuing its beauty and uniqueness. Fortunately, you will still be able to benefit from the many alternative routes of the glass.

Perhaps, one of the best ways you can enjoy better insulation in your home is by routinely maintaining the seal in between the window frame and the glass. Inadequate sealing in this area can easily increase your house's heating and cooling costs much more significantly than the window itself.

Another good tip would be to install curtains over the wavy glass windows in your home. By doing so, you effectively manage to separate indoor air from outdoor causing the enhancement of the insulation and the regulation of your home's temperature in a more cost-effective manner.

Overall, I think anyone who has antique wavy windows in their house should evaluate the opportunity that they have to either use it a beautiful masterpiece in their own home or sell it for a significant price taking profit from the demand of old wavy glass in the market. 

Enjoy this Short Film about The World as Seen Through Wavy Glass