Three-pane or double-glazed windows? Tips and prices for everyone


Choosing the perfect windows is not a simple matter. This is undoubtedly an investment for many seasons. That is why it is worth spending some time and choose windows with the best-suited parameters. Most investors are wondering if it is worth buying triple glazed windows. The answer is not clear. If we consider, for example, a passive house, then the ratio of the comprehensive costs of building a passive house to the price of three-pane windows is used. Not necessarily for traditional brick houses. Therefore, in the article below we will tell you what to look for before buying and how to choose windows to suit your needs: Upvc windows cost.

A few words about the heat transfer coefficient

The heat transfer coefficient is one of the most important parameters of windows, which is worth paying attention to. The factor can be found in the technical data of the window under the symbol Uw. We can generally assume that the lower the Uw coefficient, the greater the thermal insulation (and hence, the smaller the loss of heating energy). In UK trade we can still find PVC windows with a maximum factor of 1.8 Uw. However, windows with a parameter of 1.2 – 1.4 Uw are much more popular. We now consider this value to be standard and is typically matched by typical double-glazed windows.

Three-pane windows is a more energy-efficient solution that allows you to reduce the heat transfer coefficient below the level of 1 Uw. Triple glazing units are additionally filled with noble gas (argon), which reduces thermal permeability. Better quality products with additional fittings and a low-emission coating have a factor below 0.6 Uw. This is a typical window joinery adapted for use in passive houses.

Three-pane windows allow for significant savings. That is why they are so often used, for example, in passive houses. You can find more about the selection of windows for passive houses and the related heating savings in this article.
It’s not just the windows that matter

Double-glazed windows are already standard. However, their heat transfer coefficient can be comparable with the coefficient of poorer quality of three-pane windows. It is worth remembering that thermal insulation is calculated for the entire window (glazing, distance frame, frame). The number of chambers made of PVC also plays a big role. The more of them, the greater the thermal insulation. Wooden window frames do not have chambers. Here, the key role is played by the thickness of the frame and the method of letting the glazing into it.

What are the prices of three-pane windows compared to two-pane windows?

Double-glazed windows are relatively cheap. We will purchase the cheapest 150 x 150 cm products from just £ 90. Unfortunately, this solution is associated with a high heat transfer coefficient (on average about 1.5 Uw). We will pay at least 120 £ for a more sealed double-glazed window. Wooden models will already cost around £ 190.

Triple- are slightly more expensive. Prices for good quality glass start at £ 290 for PVC windows and £ 350 for wood products. The upper price limit is difficult to determine. The commercial offers also include 3 glazed windows with a heat transfer coefficient below 0.6 Uw. Their purchase often exceeds £ 400. Additional low-emission films and modern fittings can additionally increase purchase prices. However, the low Uw factor makes the windows very tight and are a solution designed for a typical passive house.

double vs triple glazing

Interestingly, there are already windows with very good insulation parameters, which at the same time belong to the group of so-called “Self-cleaning windows”. As the name suggests, these are windows that (of course to some extent) clean themselves.

It seems that the unit prices of windows are not too diverse. However, let us pay attention to the fact that in a typical single-family house there will be several such glazing. Therefore, the total price differences between double and triple glazing will be much larger.

As an example, consider a two-story single-family house with twelve windows. Standard double-glazed windows will cost us around PLN 1290. For better quality triple glazed windows we will already pay £ 3,290. Top price products will become an even larger investment, worth around £ 5000. We accept the window size given earlier (150 x 150 cm). In fact, the sizes of windows in modern buildings will be slightly larger, which will translate into an additional increase in expenses.