Triple Glazed Windows – Why the Extra Cost is Worth It

The triple-glazed windows haven’t been as popular in the UK as in some of the other colder countries such as Scandinavia. This could be because UK residents do not have to endure the extreme winter weather conditions prevalent in these countries. However, winters are still harsh in the UK and there has also been an increase in energy prices over the years and the trend is likely to continue. While triple-glazing units offer an excellent way to add insulation to your home, you should also pay attention to the floors, walls and roofs. However, when you neglect the windows, it will lead to condensation as well as cold spots in your home. So, should you opt for double, triple or even secondary glazing in the UK?

Advantages of Triple Glazing

Installation of triple-glazed windows in your home offers many advantages. However, a variety of triple-glazed windows are available in the market and there is a lot of difference in the efficiency among these systems. To ensure maximum efficiency from a triple-glazed sealed unit, you need to make sure that the distance between the glass panes in a triple glazed unit is 16 mm and argon gas is used to fill this gap. As you must be aware, it’s an inert gas that is known for extremely low heat transmittance capacity. If the triple-glazed unit has lower than 16 mm distance between the glass panes, its performance is going to suffer unless you choose to use another inert gas such as krypton, which is quite expensive.

For maximum efficiency, you should buy a triple-glazed sealed window with 16 mm gaps between 4 mm thick glass panes. The total width of the unit will come to 44 mm. As far as the difference between u-value of a double and triple-glazed unit is concerned, it is quite significant. A double-glazed unit is typically 28 mm wide. The u-value of a triple-glazed unit at the centre pane is 0.62 whereas the corresponding number is 1.1 in case of a double-glazed unit.

Double Glazing and Triple Glazing Comparison

If you’re wondering about the difference between a double-glazing and a triple-glazed unit, a triple-glazed unit has an extra glass pane that significantly enhances the overall performance:

  • This extra glass provides additional protection from the outside cold weather, thus keeping your home environment warm.
  • There is an additional spacer bar in the triple-glazed unit at the edge of the glass that helps in reducing heat loss through the window.
  • A triple-glazed window is more secure compared to a double-glazed unit and the middle pane in a triple-glazed unit typically uses toughened glass.
  • A triple-glazed unit offers more sound insulation provided all the other factors remain the same.
  • If you compare the energy rating, the triple-glazed units get an A++ energy rating which is the best.

Triple Glazed Units – Downfalls

If you’re worried about the pitfalls of triple-glazed units, you should know that there are certain downfalls associated with it. One of the biggest problems is the extra condensation on the outermost glass of a triple unit.

This happens because the outermost glass pane doesn’t get enough heat from inside the house, which means it can reach the dew point. The dew point happens when the temperature of the glass pane becomes lower than the temperature of the outside air and this leads to the formation of condensation.

Usually, you will see condensation on a triple-glazed unit after a cold, clear night. It could be described as light misting at the centre of the glass pane. It doesn’t happen around the edges as some heat gets transferred between the spacer bar and the frame holding the sealed unit. This means the outer edge of the glass has a higher temperature compared to the centre and this is why condensation appears at the centre.


To conclude, triple-glazing offers several advantages and you should seriously consider replacing all the windows with triple-glazed units. You will have to spend extra money but you will also benefit from higher energy efficiency in the long term. You should be able to recoup the extra investment through higher energy savings in the long run. Potential buyers will also find your property more valuable compared to a house with double-glazed units. Call KJM now to get a free estimate for double-glazed units rated A as well as the cost of an additional upgrade to triple-glazed windows.