Argon filled insulating glass VS warm edge spacer insulating glass

 In order to achieve the specific window thermal insulation requirements, we can not only optimize the thermal insulation design of the profile but also adjust the glass configuration. The application of Low E coating can significantly improve the insulation performance of insulating glass. In addition, we usually choose to use argon filled insulating glass, and replace aluminum glass spacers with warm edge spacers to improve the thermal insulation performance of the entire window.

Argon VS warm edge spacer

Since replacing the improved thermal insulation performance of filling argon and using warm edge spacer in insulated glass are similar,both them can decrease the Uw by 0.1-0.2W/M2.K ,we often have to face the problem “argon” or “warm edge”.

Filling with argon gas can reduce the Ug value in the formula for calculating Uw (windows U value) below, and replacing the aluminum spacer with a warm-edge spacer will reduce the ψg value.

Calculation formula for windows thermal insulation performance

 

Although their function to reduce the windows U value are similar and closer, the actual impact is different. Let’s take a comprehensive look at the different effects of argon filling and the use of warm edge spacers on doors and windows.

The influence on windows U value

Take the 60 series aluminium windows that use 24mm thermal break strips, the 70 series products that use 34mm thermal break strips, and the 75 series products that use 39mm thermal break strips as examples. In the initial state,glass are insulated glass with single silver low-E coating and aluminium spacer,air space.Glass combinations are 5+12A+5Low e IGU, 5+12A+5+12A+5Low e IGU,  5+15A+5+15A+5Low e IGU.

The compare is based on AHERE windows conditions and calculated with WINDOW 6.3,THERM 6.3.

Aluminium windows used to compare the thermal insulation peformance

1. Simulation resultsbased on 60 series aluminium windows( 24mm thermal break bridge strips)

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Glass Type	Glass Combination	Glass U value	Spacer Type	Windows U value
Air + Aluminium Spacer	5+12A+5 LOW-E	1.773	Aluminium Spacer	2.17
Argon + Aluminium Spacer	5+12AR+5 LOW-E	1.531	Aluminium Spacer	2.01
Air +Warm edge spacer	5+12A+5 LOW-E	1.773	Warm edge spacer	2.05

1. Simulation resultsbased on 70 series aluminium windows( 34mm thermal break bridge strips)

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Glass Type	Glass Combination	Glass U value	Spacer Type	Windows U value
Air + Aluminium Spacer	5+12A+5+12A+5 LOW-E	1.275	Aluminium Spacer	1.71
Argon + Aluminium Spacer	5+12AR+5+12AR+5 LOW-E	1.094	Aluminium Spacer	1.60
Air +Warm edge spacer	5+12A+5+12A+5 LOW-E	1.275	Warm edge spacer	1.55

1. Simulation resultsbased on 75 series aluminium windows( 39mm thermal break bridge strips)

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Glass Type	Glass Combination	Glass U value	Spacer Type	Windows U value
Air + Aluminium Spacer	5+15A+5 +15+5LOW-E	1.225	Aluminium Spacer	1.62
Argon + Aluminium Spacer	5+15AR+5 +15AR+5LOW-E	1.080	Aluminium Spacer	1.52
Air +Warm edge spacer	5+15A+5 +15A+5LOW-E	1.225	Warm edge spacer	1.43

With above tests,we got conclusions:

1. For most conventional window types, choosing to fill the insulating glass with argon gas and replacing the aluminum spacers with warm-edge spacers can reduce the entire window U value by about 0.1-0.2W/m2K”.
2. For double glazed unitswith 12mm spacer, the influence argon is better than using warm edge. For the triple glazed units, whether it is 12mm or 15mm spacer,warm edge spacer has much better thermal insulation performance than argon filled glass units. Especially for the 15mm,the reduction of U value is almost twice that of argon filled units.

The influence on windows&doors condensation

The condensation of doors and windows mainly depends on the temperature of the indoor surface and the indoor humidity. The higher the indoor surface temperature of doors and windows, the less likely it is to condense; the lower the indoor humidity, the less likely it is to condense.Today we will mainly talk about the temperature of the indoor surface of doors and windows.

glass condensation

For normal windows &doors with insulated glass,the lowest temperature happened on the glass edge area,while the temperature of the glass center,and aluminium frame inner surface are relatively higher,That’s the reason why glass condensation always happened on the glass edge.

Below is a simulation result based on the 60 series windows,the temperature of the windows& glass are very clear:

windows temperature difference-aluminium windows+insulated glass

The temperature at the glass edge is 0.9°C-2.7°C, and after filling the insulating glass with argon ,the temperature of the glass edge is 1.2°C-3.0°C, which is slightly higher. However, if you use Technoform warm edge spacers, the edge temperature of the glass can be increased to 4.1 ℃ -5.5 ℃, and the average temperature increase will reach about 3 ℃.

After being filled with argon, it doesn’t increase the thermal break performance of the windows&doors weakest part -glass edge , but increase the glass center that is already has the best performance,the glass edge which has high condensation risks is not increased. Therefore, for the control of door and window condensation, the effect of argon filling is not obvious.

 

The simulation result on 70 and 75 series aluminium windows are similar:

After using the warm edge, the thermal insulation performance of whole window is more balanced, and there is no obvious weak parts in the window. While using argon filling ,the balance of thermal insulation performance of each part of the window has been further broken. The result of argon filling is to further improve the thermal insulation performance of the central part of the glass, which has relatively good thermal insulation performance, while the edge of the glass with the weakest part has not been optimized.

 

The lifetime of argon gas and warm edge spacers

The argon will slowly leak over time, and this will affect the insulation performance of the insulating glass. Even if the units is well sealed, it cannot completely prevent the leakage of argon, but can only reduce the rate of argon leakage.

The warm edge spacer used has the same lifetime as the insulated glass,so we don’t have any worry about the performance decrease after years.

The price between argon gas and warm edge spacer

Argon filled insulated glass is about USD1.5/SQM higher than normal glass with air.Warm edge spacer price is about USD2/SQM higher, it depend on the warm edge spacer brands, the international brands Morn usually use are Technoform, Fenzi, Lisec and other brands.Some China manufacturers also have warm edge products but the performance is relatively poor.

Lisec insulating line -MORN-CHINA

But what we should be clear is:There’s not many methods to precisely detect the argon content,some glass manufacturers still using very lagging machines to fill the glass and cannot guarantee the actual content (usually 85-90% argon content is required).Some insulating glass production line manufacturers such as Bystronic,Lisec already has lines that can fill gas online and detect the content.

Here we recommend a machine to detect the argon content precisely.

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Both argon and warm edge can increase the insulating glass thermal insulation performance,we suggest using them together, combing with high performance low-E coatings,the glass U value will be decreased to only 0.6-0.8W/M2.K.

Insulated glass manufacturer-MORN-CHINA-double glazed units

Morn is your turnkey insulated glass manufacturer and supplier in China,welcome contact us if you got any questions.

Download this article here:Argon filled insulating glass VS warm edge spacer insulating glass

Select the right Secondary sealant for your insulating glass

 Insulating glass has been widely used in commercial buildings, shopping malls, high-rise residential buildings and other buildings, with excellent heat insulation, energy saving, sound insulation and other properties. The secondary sealant used insulating glass plays an important role in maintaining the stability of the insulating glass structure, and greatly affect the quality and service life of the insulating glass. The insulating glass structural sealant is even directly related to the safety of the curtain wall.

insulating glass structure

The structure of insulated glass

Two pieces of glass are separated by a spacer, the spacer and the glass are first sealed with butyl, which can prevent water vapor or inert gas from entering and exiting the cavity. But the butyl rubber itself has low bonding strength and low elasticity. the spacer is filled with molecular sieves, and the gap between the edge of the glass and the outside of the spacer is sealed with a second sealant.to maintain a good structure when under load.

What are the problems caused by improper selection of the secondary sealant for insulating glass? This article summarizes the hazards into the following two categories: the thermal insulation loss of the insulating glass ,and the safety application of insulated glass.

The defect of using bad quality sealant

The main manifestations of this type of problem include the phenomenon of “rainbow” and “oil flow” in insulating glass. The phenomenon of “water accumulation” and “condensation”, slippage of insulating glass spacers, etc.

1. Rainbow Rainbow is a kind of oil film that appear inside the insulated glass,see below picture:

rainbow -oil film inside insulated glass-quality problem

2. Oil flow .Oil flow means the PIB inside the glass have oils or dirty.

insulated glass-oil flow

The above two situations are related to the filling of “white oil” in the secondary sealant. “White oil” is commonly known as mineral oil. Mineral oil is a hydro-refined petroleum fraction, which is mainly a mixture of saturated naphthenic and paraffinic hydrocarbons. Its chemical structure is obviously different from that of organic silicon materials and has poor compatibility with silicone sealants. , It will migrate and ooze after a certain period of time.

The “rainbow film” phenomenon is caused by the migration of “mineral oil” into the inner cavity of the insulated glass; and the reason for the “oil flow” phenomenon is that during the migration process of “mineral oil”, the primary butyl is dissolved, resulting in Black oil spots or oil stains.

These “mineral oils” may come from the secondary sealant for insulating glass, and they may also come from the weather-resistant sealant or door and window sealant that is in contact with the secondary sealant.

insulated glass quality problem-oil paint inside glass

Above picture shows the rainbow film caused by the oil.Since the weather-resistant sealant is in contact with the second insulating glass sealant, the “mineral oil” in the weather-resistant sealant migrates to the second insulating glass sealant, then to a butyl, and finally to the inner cavity of the insulating glass.

insulated glass quality problem-PIB dissolve

The door and window sealant is partly in contact with the glass secondary sealant, so the “mineral oil” in the door and window sealant migrates to the secondary insulating glass sealant in contact with it, and then migrates to the PIB, which finally results in lprimary butyl is dissolved and oil flow occurs.

Actually the mineral oil are not only exist in the weather-resistant sealant,but also the glass secondary sealant.For competitive market,some sealant manufacturers sacrifice the product quality and performance,mineral oil was added into the product to decrease costs.The bad quality sealant will cause oil paints,low bonding effect with the PIB,and even compatibility problem with the PIB.That’s what we;ll discuss below:

3. Glass dew or condensation.

The phenomenon of dew and condensation of insulated glass refers to the water vapor entering the cavity condenses into dew or even water after the glass lost its sealing effect,and thermal insulation performance.

insulated glass dew-water inside glass-morn

4. Slipping of insulating glass spacer

The slipped spacers means that spacers and the second sealant are not well bonded, and they slip in the cavity due to internal stress.

spacer slipping inside insulated glass

5.Falling of insulated glass.

There’ll be some safety risks that caused by improper sealant,especially the falling of insulated glass from the buildings.

glass falling down from buildings

In 8^th,July,2011, one piece glass falled from 21^st floor in Hangzhou ,the falling glass hit a girls leg and caused amputation.The reasons of glass falling is,the improper using of secondary sealant of the insulated glass,the glass used polysulfide sealant but not structural silicon sealant.

Polysulfide sealant has poor UV aging resistance. If polysulfide sealant is selected as the second-sealant i, the bonding surface will be exposed to sunlight for a long time, and the bonding effect will decrease and cause glass falling down.

What kind of secondary sealant should we use in glass for projects?

For different curtain wall systems,our suggestions are below:

1. Point supported glass facade:Must be Structural silicon sealant .
2. Hidden frame curtain wall,semi framed curtain wall:Must be Structural silicon sealant .
3. Large area stick curtain wall:It’s suggested to use Structural silicon sealant .
4. Windows,doors,normal stick curtain wall:Silicon sealant,polysulfide sealant.

insulated glass production-morn

What methods should we should take to guarantee the sealant quality?

a: Before insulating process, confirm that the sealant has a good bond with the substrate, and conduct a bonding test and compatibility test;

b: During the processing, continuous extrusion test (snake test), butterfly test, and break time test should be carried out;

c: Check the quality of the sealant injection, it should be full and dense to ensure that the sealant is fully in contact with the butyl glue and flush with the glass edge;

d: In order to confirm the bonding quality of the sealant and the substrate, the finished insulating glass should be subjected to a tapping peel test.

finished insulated glass-MORN-CHINA

What sealant brands we can use in China？

The popular sealant brands in China include Silande,Lingzhi,Baiyun,Guibao.All these factories has good quality to ensure the overall insulated glass performance and safety.

Morn is your turnkey insulated glass manufacturer and supplier in China,welcome contact us for more info if you got problem purchasing insulating glass from China.