Argon is an inert (non-reactive, non-toxic, colourless, and odourless) gas that is used within insulating gas units (IGUs) to enhance thermal performance. Since windows have a fairly low R-value (the capacity an insulating material has to resist heat flow), every improvement including extra glazing layers, low-e (emissivity) coatings, and gas fills help to improve efficiency.
Windows that contain argon feature a sealed unit comprising two or more panes of glass with argon gas filled between them. Argon is the third most abundant gas in the atmosphere at 1 per cent, after Nitrogen (78 per cent) and Oxygen (21 per cent). It is distilled from air during the production of liquid oxygen and nitrogen.
Argon-gas-filled windows offer a range of benefits, including:
Increased Energy Efficiency
Compared to the other commonly used noble gases, namely Xenon and Krypton, Argon is the most abundant in the atmosphere, which makes it the most cost-efficient inert gas for insulation purposes. The fact that it is denser than air gives it a lower U-value (measure of heat flow) than air, meaning it conducts less heat.
In other words, double-glazed windows with argon gas in between lose less heat than single-pane windows or double-glazed windows filled with air. Argon filled windows help minimize the amount of solar radiation passing through the glass during summer, while maintaining a higher indoor temperature during the cold months.
Although the difference in R-value between air-filled window panes and argon-filled windows is fairly low, the small improvements in R-value can considerably impact the energy consumption of your home or building, especially when a room has many windows.
R-value refers to the window’s resistance to heat conduction, and is the inverse of the U-factor. So, the higher the R-value (or lower the U-factor), the better the window efficiency.
If you are keen about your home energy bills, you must have noticed that the actual cost of energy is improving, but your bills are not. Depending on your source of energy, it is likely that your cost per unit of energy has reduced over the years, though this may not reflect in your heating and cooling bill. Old, inefficient windows can waste energy in your home, causing you to spend more than you should in heating and cooling your interior space.
Since old windows are typically single-paned, they tend to be drafty and inefficient, resulting in heat loss through the glass and any spaces around your windows. Argon-filled windows address these issues by insulating your home and reducing the transfer of heat through the window.
Argon is non-reactive, and has a thermal conductivity of about 30 per cent lower than air.
Argon gas windows offer improved thermal insulation efficiency by bringing the temperature of the interior window pane closer to room temperature. This process essentially reduces drafts and air currents that occur when different temperatures meet.
So, the gas acts as an insulator during the cold winter months and the hot summer months to protect the inside from extreme outside temperatures, reducing drafts and cold spots.
The fact that the interior glass of argon-filled windows is closer to room temperature during the cold months (higher than outside temperature) helps to reduce frost and condensation.
Argon is completely safe; so even when the filled glass unit breaks, the occupants are not in any kind of danger from the gas.
Over time, it is not unusual for argon gas to leak out of the sealed space between the glass panes. The amount lost usually depends on the quality of the build, since some gas tends to diffuse through the seals. Argon leaks also occur when the seals between the glass and edge spacer fail.
Fortunately, the gas is not dangerous, and the effect is minimal. In fact, studies show that an annual argon gas leakage of 5 per cent will only result in 12 per cent loss of the window’s value after 20 years.
Reduced UV Radiation
Although argon-filled windows by themselves have little effect on the amount of radiation passing through, manufacturers usually apply a low-e coating to at least one of the glass surfaces. This coating helps to reduce radiant heat transfer across the air space within an integrated glass unit.
For instance, a double-glazed argon-filled unit at R-2 can increase its R-value to R-3.3 when a low-e coating is applied to one of its glass surfaces. This is a 67 per cent improvement in energy efficiency. Additionally, low-e coatings block selective sunlight wavelengths from passing through, reducing the Solar Heat Gain Coefficient (SHGC).
So, combining argon-filling with low-e coating can help manage summertime heat, and the associated fading and damage to interior furniture, flooring, and finishes, while maintaining sufficient levels of light for indoor plants to thrive.
Other Benefits Of Argon-Filled Windows
Besides improved energy and thermal efficiency, there are other merits you may enjoy by installing argon-filled windows, such as:
- Increased sound proofing
- Cost effective in the long-run through energy savings
- Comfortable in all climates
- Argon will not corrode the window material like oxygen (air)
- Improved all-round performance by installing triple-pane windows instead of double-pane windows with argon gas
Argon-filled windows offer many benefits, but you should ensure that they are properly installed by a professional, and sealed properly for you to enjoy the benefits for as long as possible.