Double-pane windows, also known as insulated glass units, are windows made up of two glass panes. There is an air pocket in between the glass panes to reduce heat loss, and it also reduces the effect the temperature of the external air has on the internal atmosphere.
The air pocket can also be filled with inert gases for better insulation. Inside the air-pocket is a desiccant. The role of the desiccant is to stop condensation from forming on the windows.
Double-pane glass and insulated units are highly resistant to heat and sound. These are made possible, thanks to the core features of double-pane windows. Let’s take a look at some of these core features below.
E-Coating to radiate energy
Heat energy (infrared light) is transmitted into buildings as heat. Solar heat is referred to as short-wave energy, while heat energy is referred to as long-wave energy because they have higher wavelengths when compared to heat from the sun.
Glass windows have emissivity. This refers to the ability of glass windows to radiate energy. The emissivity of glass is one of the ways windows lose heat to the external environment made possible by radiant energy. If the emissivity of a glass pane is reduced, the insulating property of that pane is increased.
That’s why we have e-coating. E-coating, fully described as low-emissivity coating, is a transparent and very thin layer of coating. It bounces back long-wave infrared energy forms from the glass surface. Other e-coating types also bounce back short-wave energy.
E-coatings were produced to bring the amount of infrared light and ultraviolet rays that can pass via a glass pane to the barest minimum without adversely affecting visible light transmissions.
The e-coating prevents heat loss by reflecting the heat, which otherwise would have escaped from the home to the external environment, back into the house during winter. The process is reversed during summer, and heat is kept out of the home to make the internal atmosphere cool.
Insulated Gas to lower energy bills
The air-pockets between double-pane windows are filled with air or inert gases. While an air-filled double pane window will still offer some insulation, a gas-filled double-pane window will provide your home with better insulation.
Instead of filling the air-pockets with air, gases are used instead to slow down heat transfer through the surfaces of glass windows. The commonly used insulated gases in double-pane windows are argon and krypton.
Argon is commonly preferred because it is affordable and still provides better insulation than air-filled double-pane windows. Argon is most times combined with low-E coatings for improved window insulation.
Krypton gas is considered premium because it is quite more expensive than argon. As a result, it is not a commonly used insulated gas for double-pane glass. At the same time, it may be on the high side, but windows that make use of krypton-filled double-glazing experience superior thermal insulation. A krypton gas-filled window can lower your monthly energy bill by about 40 percent.
Gas provides better insulation compared to air because air is made up of moisture, which could lead to condensation on your double-glazing. Gas, on the other hand, is denser, and this reduces air infiltration and reduces the speed through which air can travel. The result is superior thermal insulation for your windows.
Double-pane insulated windows provide your home with improved thermal insulation and sound resistance. They help to keep the cold out of your home and retain the room’s internal temperature to create a comfortable atmosphere in winters.
This is made possible by the presence of air-pockets (i.e. made possible by spacers). The air-pocket slows down the movement of air, which reduces the speed with which heat is lost out to the external environment in winters.
The structure also helps to reduce the speed at which sound penetrates through your windows into the home. The presence of an extra glass pane alongside the air-pocket works to keep internal noise within and external noise out of your home.
A single-pane glass window cannot provide this protection and thermal insulation because it lacks the structure to provide such benefits.
Type of Glass
The type of glass used in a double-pane window also contributes to its resistance to heat and sound. Annealed glass and tempered glass are some of the common glass types used in double-glazing. Laminated glass is also used but is not as common as tempered or annealed glass, and a bit expensive option.
- Annealed glass is preferred because it is affordable and has been in use for quite some time. It is prone to shattering and breaking. It also breaks into large glass shards that may give room for safety concerns. Although its strength is improved when installed as a double-glazing.
- Tempered glass refers to annealed glass that has been put through the heat tempering treatment to make it sturdier and durable. It is resistant to shattering, and when it does shatter, it does so as small dull pieces that cannot cause harm. This makes it a safety glass and is hard to break as a double-glazing. It costs more to have a tempered double-pane window.
- Laminated glass is a security glass. It simply refers to a sandwich of multiple glass layers with a plastic sheet of polyurethane or ethyl vinyl acetate inserted in between the layers of glass. Instead of breaking to pieces or glass shards when it shatters, the plastic interlayer holds the glass pieces together to form what resembles a spider web.
Tempered glass and laminated glass improve the thermal insulation and sound resistance of an insulated unit when selected as the glass type.
Window Frame Material
The frame material used for your double-pane glass will also impact on its thermal and sound resistance. The commonly used frame materials for double-glazing are uPVC and aluminum frames.
uPVC is widely used as window frame materials for double glazing. It is less expensive compared to aluminum and is available in a variety of finishes and colors. It aids the insulation of double-glazing because it also contains an insulating material, and it is straightforward to maintain.
Aluminum frames are lightweight but are secure, strong, and durable. When used for double-glazing, they most of the time include an insulating strip that will aid the insulation of your windows. The problem with aluminum is that it may corrode, especially in coastal areas.
The double-pane glass will improve the thermal and sound resistance of the windows in your home. For better insulation and sound resistance, consider upgrading your glass windows to double-glazing.