When it comes to getting replacement windows for your home, you surely want to do better than a single pane of glass. In fact, building regulations dictate the need for better glass that has improved thermal performance and lower heat loss. Your investment decision will likely come down to double glazing vs triple glazing.

Choosing between double or triple glazing when you have new flat roof skylight windows installed is an important thing to think about. It can make quite a big difference in terms of initial costs and energy bills down the line.

In the following guide, we will take a closer look at double and triple glazing comparing these two options and their benefits and drawbacks.

What is double glazing?

Two panes of glass make a double-glazed window. The idea of the panes of glass is to serve as a barrier between the outside and the inside of the house. It is the gap between the panes that help in keeping heat in the house during the colder months. Double glazing is reasonably priced and has good energy efficiency ratings. It doesn't take long for double-glazed windows to show their benefits compared to single glazing. Homeowners that make the upgrade to their existing windows quickly note the lower energy bills after their initial investment.

The pros of double glazing

  • It is cheaper than triple glazing
  • Works well to reduce heat loss
  • It is very popular and widespread across the UK
  • Good at noise reduction

The cons of double glazing

  • The energy efficiency of double-glazing is lower than that of a triple-glazed window
  • Double-glazed windows are less secure than triple-glazed windows

What is triple glazing?

Triple-glazed windows are different from double-glazing in that they contain three panes of glass along a sealed frame. There is a pocket of gas between each of the panes, usually argon. It is heavier than air and serves as an insulator for noise and heat. This extra pane in triple-glazing windows creates two locks that boost thermal efficiency and can improve the heating bills of the household.

But it is not just the extra layer that improves energy savings. Other variables are at play as well. For example, the type of inert gas used in the space between the inner and outer panes, the glass thickness and the warm edge spacer bars along the edge helps prevent energy loss from the inside.

The pros of triple glazing

  • Superior noise reduction properties compared to double-glazing and single-glazed windows
  • Very durable, with a high lifespan of 30 years
  • Better security due to the third pane adding another layer of glazing
  • Low U value
  • The additional pane makes window frames very energy efficient and a great choice for pitched roof skylights

The cons of triple glazing

  • More expensive manufacturing techniques with higher carbon emissions
  • There is a price difference when it comes to double glazing vs triple glazing in favour of the former
  • Triple-glazing units have a heavier load on the frame
  • The UK climate doesn't always call for triple-glazed windows

Learn more about what goes into the price of triple glazed windows.

Double glazing vs triple glazing comparison

Now that you know more about double and triple glazing, you will want to know which of these options is better for your home. It is clear that upgrading single glazing windows is an absolute must.

Building regulations state that your home's windows require a certain standard of U value so that they lose less heat. Single-pane windows simply cannot meet the standard and so you have to choose double or triple glazing. Below we will see how the two of them compare in regard to the most important factors.

Which has better Energy Efficiency?

Measuring performance to see which window option has the better energy efficiency is a matter of comparing the U value. This is the same method used for walls, roofs and floors. A lower U value means that the glass can keep the heat in during the cold months, or prevent the hot air from forming coming in during hot weather.

Single glazing leads to major heat loss, with a U value of around 5.0W/m²k. Even old double glazing can score about 3, whereas for new windows that value can be improved to about 1.5. With triple-glazed windows the U value is at its best, sometimes reaching 0.5, which means minimal heat loss.

Which Deals Better With Condensation?

It should be no surprise that triple-glazed windows are better at dealing with condensation. That is because the third pane of glass makes it so that there is less difference in temperature outside and inside the house. Condensation is not a small problem and you should not ignore it. If your double glazing leads to condensation, you should look to upgrade to triple glazing or consult with an expert to rectify the problem. Otherwise, you risk damage to window frames and excessive moisture. If your current double glazing is not seeing any condensation trouble, you may not need to worry about it.

Which is better for noise reduction?

If you live in a built-up area with heavy traffic, you will welcome any noise-reduction window upgrades. Double glazing can definitely help with that, and so can triple glazing. Still, you need to consider some important factors in that regard:

  • Glass thickness plays the most important role in noise isolation. Sometimes it is best to choose a configuration with a different thickness for each pane of glass. That way it will block out different sound frequencies.
  • The size of the gap between the panes also plays a role. The larger the gap, the better the noise isolation properties.
  • The middle pane in triple glazing can sometimes increase sound vibrations, creating an echo chamber effect.

If you are looking for windows that can specifically reduce the noise, you can consult with an expert. They can recommend specialised solutions like laminated glass. It is not always the case that triple-glazed windows are the best option, even though in theory they should be better sound isolators. Sometimes two panes of laminated glass in double glazing works impeccably for the purposes of noise reduction.

Will Triple Glazing Add Value to My Home?

The answer to this question is absolutely yes. The government is always under pressure to reduce carbon emissions and the public conscience is focused on global warming problems. It means properties that are more energy efficient are looked on more favourably. This naturally means double and triple glazing upgrades to existing frames are a good selling point and add good value to your home.

Let's talk about the price difference in double vs triple glazing

It is no secret that the main drawback of triple-glazed windows is the price tag. The manufacturing techniques and materials used in adding another pane of glass increase the price and make the triple glazing cost a bit steep. And while it is true that triple glazing leads to cost savings down the road compared to double glazing, the difference may not be as significant.

Three panes of toughened glass may lead to fewer cold spots and greater efficiency in solar gain, but those are differences mostly evident in cold climates. What this means in the debate of triple glazing vs double glazing is that it may not be immediately obvious which option to go for. For self-builders, who have experienced the comfort factors of better noise reduction and more energy-efficient triple-glazed windows, the decision to pay more comes easily. But for those that are not too scared of the UK climate, or simply don't have a north-facing part of their homes, choosing double-glazed windows makes more sense.

Is it worth replacing double glazing with triple glazing?

When choosing between triple glazing vs double glazing, one needs to consider a variety of factors. For homes that receive little natural light and need as much heat as possible to stay warm in the winter months, triple glazing may be a fine solution. But the steep cost of the product and the installation process may be too prohibitive and not worth the investment for homes that already make good use of existing windows with double glazing. Sometimes renewing double glazing can be all it takes to improve the U value of the windows.

Knowing more about double and triple-glazing options can enable you, as a homeowner, to make the best decision for your house. While triple glazing has its benefits, the investment in some cases may not be worth it in the long run. Check out our article on Is Triple Glazing Worth it for more information.


What are the disadvantages of triple glazing?

The main disadvantage of triple glazing is the steep cost to upgrade your windows. Also, the extra thickness of the glass in triple glazing can sometimes impact the amount of sunlight entering through the window.

Is triple glazing worth the extra money?

Yes. Triple-glazed windows are more expensive, but they contribute to additional comfort to a living space. This makes it worth it for those that can invest in this kind of window as they can save money on bills.

Is triple glazing any better than double glazing?

Triple glazing is better for homes with north-facing windows because it is much more energy efficient. Properties exposed to extreme weather can greatly benefit from the qualities of triple glazed windows.

Is triple glazing much more expensive than double?

Triple glazing is 30% more expensive than double glazing, on average. This means that it is not as affordable and the manufacturing and installation costs make it a bit prohibitive for homeowners looking to upgrade a greater number of windows on their homes.