Thermals
What is a thermal sealed unit?
A thermal sealed unit is a composition of several panes of glass which are fixed together by one or more middle strips called “interlayers”, and a sealant all around the components which holds them together. Between each pane there is an air or gas space which provides insulation between the two external spaces on either side of the sealed unit. Its role is therefore to allow light to pass through, while constituting a thermal barrier creating resistance to temperature exchanges.
Why and when to replace a thermal unit?
There are 3 causes leading to the obsolescence of a thermal sealed unit:
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- Thermal unsealing occurs when the seal around it cracks or breaks. When the seal of the thermal unit is being compromised, air and humidity infiltrate it and argon gas (if there is any) escapes. The thermal unit therefore no longer insulates properly and must be replaced.
- When a thermal unit is energy efficient (see description on our site: Energy efficient thermal unit with argon gas and low-emissivity Low-E film), the low-emissivity film, commonly called Low-E film, can, over time and with continuous exposure to the sun over the years, become multi-colored, have colored reflections or even cause spots in the glass. These are signs of degradation of the film which means that it no longer adequately reflects the sun’s rays. Once again, the thermal unit must be replaced in order to insulate adequately.
- Obviously, when the glass is cracked or broken, the thermal unit must be replaced for reasons of safety and energy efficiency.
How do you know if the thermal unit is unsealed?
The most common sign that a thermal unit is unsealed is the appearance of mist or droplets inside the unit itself, namely between the windows. This sign is a symptom of the thermal unit loosening. It’s possible that the mist or droplets evaporate when the temperature is high enough, but the unit still remains unsealed.
Is defogging effective?
No, defogging is not effective, because it does not reseal the thermal unit. Defogging helps dry out the droplets trapped in the unit and lowers the humidity level to make the thermal unit as translucent as before, but it is only a matter of time before it becomes foggy again. The unit itself still remains unsealed, so it no longer insulates properly and the only permanent solution is to replace it.
Different types of thermal units for different performances and multiple uses
There are a multitude of different compositions possible when we talk about thermal sealed units. These compositions are distinguished into 2 main categories: Thermals for residential use and thermals for commercial/industrial/institutional use.
Residential windows:
Residential thermal units often have the following composition: 3mm single glass – aluminum interlayer – 3mm single glass with argon gas and Low-E low-emissivity film. This is what we call an energy-efficient 3mm double thermal unit. For very large windows, it’s possible that the glass used is one or more millimeters thicker, in order to increase its strength for handling and transport.
Residential patio doors:
Patio door thermal units have a composition that is distinguished by the tempering of the glass. Often, we’ll have the 4mm tempered glass composition – aluminum interlayer – 4mm tempered glass with argon gas and Low-E film. Given the purpose of the patio door, the windows must be tempered for safety reasons. So, if an accident were to happen, such as someone tripping in front of the patio door and breaking the glass, for example, the tempered glass will shatter into thousands of blunt pieces, instead of large, sharp and potentially dangerous pieces.
Residential interlayers:
The interlayer represents the middle strip(s) between each window of a thermal unit. The residential spacer, the most common of all, is made of aluminum, but there’s also the white plastic spacer and the black plastic spacer. Although the choice of one or the other is often made for aesthetic reasons, plastic dividers insulate more than aluminum dividers, without increasing the price of the unit. It’s therefore wise to choose a plastic interlayer, when possible.
Curtain wall and commercial/industrial/institutional windows:
The installation of thermal glass in aluminum or steel mullions, forms what is called a curtain wall. This type of structure is very often present on the facade of businesses, in order to give a view inside them, and let in light from outside. The types of thermal units that can make up the curtain wall and commercial/industrial and institutional windows are very varied. Going from standard, laminated, tempered to wired glass, they can be designed to be extremely insulating for temperature, sound, safe in the event of breakage and/or to be impact resistant. In addition, there are more types of interlayers compared to the residential sector, allowing increased insulation. Our advisors will be able to help you make an informed choice among the different possible compositions, so that your thermal unit is suitable for use.
Thermal warranty
Almost all of the thermal units that we change have a 10-year manufacturer’s warranty. This guarantee covers the watertightness of the thermal unit during the said period. We also offer 1 year warranty on labor (installation) and 1 year against thermal breakdown.
Thermal breakage
When a thermal glass breaks suddenly without an apparent point of impact, there’s a good chance that it’s caused by thermal breakage. This phenomenon is characterized by glass cracking or breaking when there’s a rapid change in temperature, or a drastic temperature difference on each side of the glass. This is a very rare phenomenon but, from time to time, the glass of a thermal unit can break in this way.
Here are the different options and most common components of thermal units:
Energy-efficient thermal unit with argon gas and Low-E low-emissivity film
When a residential thermal unit has a gas (argon) inside the windows, and the exterior window has a reflective film stuck to its internal surface, we’re referring to an energy-efficient thermal unit. Argon is a gas that has a higher insulating feature than air; it therefore serves as a thermal barrier between the 2 panes. As for the role of the Low-E film, it aims to reflect and therefore repel the sun’s rays, thus reducing the greenhouse effect inside the building. This duo, applied to all the thermal units in a building, allows to maintain its coolness in summer and heat in winter .
Triple glazed thermal units
A triple glazed thermal unit is a process by which another space of air or gas is added using the addition of another interlayer and another pane of glass. A common composition of triple thermal glass is 3mm glass – aluminum interlayer – 3mm glass – aluminum interlayer – 3mm glass with Low-E film with all spaces filled with argon. The main advantage of the triple thermal unit, compared to the double one, is it provides increased insulation by creating another thermal barrier, thus preventing temperature exchanges. Sound insulation is also increased.
Thermal unit with laminated glass
Lamination is a process by which 2 panes of glass are glued together with one or more plastic films, of varying thickness, to form a laminated pane. This process, applied to one or more of the glasses in a thermal unit, can have several functions. Lamination helps secure the glass by ensuring that, in the event of breakage, it’ll stay in place instead of collapsing to the ground. It also constitutes as a barrier, because it’s much more difficult to pass an object through laminated glass than standard glass. Lamination also gives a sound-absorbing feature to the glass by absorbing sound vibrations. The thicker the plastic wrap, the more soundproofing the laminated glass will be.
Thermal unit with tinted, textured or satin lenses
One or more windows making up the thermal unit can also be tinted, textured or satin-finished, thus providing an aesthetic appearance and/or granting privacy. Indeed, these characteristics can ensure that light passes through the thermal unit and provide privacy, preventing you from seeing through it. Very often, this is what we find on the thermal units on the front doors of residences. The most popular textures for this use are Pinhead-Morocco and Glue-chip.
Thermal unit with tempered glass
Glass tempering is a process by which a pane of glass is heated to a high temperature before being suddenly cooled. By doing this, the outer molecules of the glass cool much faster than the inner molecules, creating compression inside the glass. This compression gives the glass increased resistance to impact and thermal breakage, compared to standard glass and, if the glass were to be broken, the compression would be released suddenly, causing the tempered glass to collapse into thousands of non-sharp pieces, instead of large, potentially dangerous pieces. Tempering the thermal glass therefore provides increased resistance to impacts, thermal breakage, and better safety in the event of breakage. – Ask for a quote