What is the Difference Between Double-Glaze and Triple-Glaze Windows?

Double-GlazeThere are a number of important differences between double-glaze and triple-glaze windows. Both serve the same purpose: to better insulate your home and reduce your heating and cooling costs. However, there are a number of subtle differences in how they accomplish that goal.

Two is Better than One

In the past, windows consisted of just one pane of glass. However, as they attempted to make homes better insulated, architects found that by using two panes of glass separated by a layer of air or inert gas they were able provide much better insulation. That is because glass transmits heat much better than air does. The layer of air between the two panes of glass provided an extra layer of insulation that made it more difficult for heat to get in or out of the home. That invention became known as a double-glaze window. A triple-glaze window takes that innovation to the next step by adding a third pane of glass with another layer of air or gas as insulation. However, it did not provide nearly the same dramatic improvements over double-glaze windows that double-glaze provided over single-pane windows.

Measuring Heat Flow

The amount of heat that a window lets in or out is measured by something called the U-value. A high U-value means a window lets a lot of heat through. A low U-value means the window is efficiently insulated and lets through very little heat. A single-pane window can have a U-value of over 5. By comparison, U-values for double-glaze windows fall between 1 and 2. Triple-glaze windows score even better, with U-values of 0.8 not uncommon.

Heat Absorption

By simply comparing U-values, triple-glaze windows are a lot more efficient than double-glaze windows, according to Home Building. However, that ignores one important disadvantage of triple-glaze windows. Each pane of glass absorbs sunlight and heat, so during the cold months a triple-glaze window not only lets less heat escape your house, but also counteracts it by letting in less of the sun’s warmth as well. Because of this, quadruple-glaze windows, featuring four glass panes, are not very popular outside of very specific applications.

Triple-glaze Pros and Cons

The biggest argument in favor of triple-glaze windows remains their incredibly low U-value. By being very efficiently insulated, they can keep your home a comfortable temperature and save electricity and heating oil. Because they are bigger and use more layers of glass, they are also more durable and provide a degree of soundproofing as well. However, they tend to be heavier and larger than their double-pane counterparts. More importantly, triple-glaze windows are significantly more expensive and generally come in fewer styles oriented for high-end projects. That can make finding the right style of triple-glaze window for your home harder.

Double-glaze Pros and Cons

While not being as well-insulated as triple-glaze windows, double glaze windows still offer an enormous improvement over single-pane windows. They are also quite light compared to triple-glass windows and offer a very good value for their price point. Because double-glazing is considered a standard in many states and countries, a very wide variety of sizes, styles and designs of double-glaze windows is available.

Good Insulation

As can be seen, the choice between double-glaze windows and triple-glaze windows can be a difficult one, as each person and each project have their own requirements. However, despite the difference between double-glaze and triple-glaze windows, both are a great option to improve the insulation of your home.

Related Resource: Fiberglass Windows