Single glazing for modern housing construction or for renovating older buildings? This is no longer permitted and is a thing of the past. A house with single glazing loses five times as much heat as one with double-glazed windows. On top of that come further drawbacks. Single-glazed surfaces are poorly insulated and often have leaky window joints. In winter this leads to condensation forming on the inside, and in especially cold temperatures even to ice crystals forming. Before multiple glazing came into use, there were various ways of counteracting these disadvantages - for example rubber seals, insulating films or energy-saving secondary panes. However, they fell far short of the quality of the low-emissivity glazing that is standard today.
Construction and measurement technology
How well glazing protects against heat loss is measured by specialists using the heat transfer coefficient (U-value). The smaller this figure, the better the insulation. For windows with double low-emissivity glass this figure is between 1.5 and 1.1 - with triple glazing it is as low as 0.9 to 0.5. While the step to double glazing was quite a quantum leap in its day, the current standard is clearly triple glazing: in passive houses it is already mandatory today. In the early days of this development, manufacturers filled the space between the two panes with hermetically sealed air. Nowadays, however - as with triple-glazed windows - it is standard to fill this space with an inert gas, preferably argon. This has two effects: in winter less heat is lost to the outside, and in summer these windows protect against heat penetrating in. In the transitional seasons this prevents heat flowing in from outside and may, in those weeks, cause slightly higher heating costs. Manufacturers also make use of the option, with multiple glazing, of coating the panes with metal vapour. This reflects long-wave infrared light and provides a further thermal insulation effect.
Renovating older buildings: combine triple glazing with façade insulation!
When modernising older buildings - energy efficiency is often one of the reasons for doing so - it is advisable to check the building's insulation before choosing windows. If you opt for modern triple glazing, the window frames also need to reflect the current state of the art. If the frames are poor, draughts are likely and heating costs remain just as high. Having windows and frames installed by experienced specialists is equally crucial. If the connections to the wall are not right, heat will continue to be lost.
One very important note: triple-glazed windows in older buildings should ideally be installed together with façade insulation. Otherwise the following trap looms: the improved windows reduce air exchange, made worse still by inadequate ventilation. But because the façade does not yet possess this new quality, mould forms on the cold walls. If façade insulation cannot be carried out at the same time as the window installation for structural or financial reasons, it should follow soon afterwards. The window renovation should be carried out beforehand in such a way that it does not hinder the subsequent façade insulation. Incidentally: if a renovation meets the statutory energy-efficiency requirements, a subsidy from public funds may be available.
New EU standards from 2021
By 2021 at the latest, triple glazing is expected to become mandatory across the 28 states that currently make up the European Union (EU). From then on, the nearly zero-energy standard will apply to new buildings - and to public buildings as early as 2019. Triple-glazed windows currently cost a little more to purchase than conventional material. Yet this investment always pays off - and, given energy prices that mostly keep rising, perhaps sooner than initially expected.
You would rather not wait that long and start saving on heating costs now? You can request a no-obligation quote from us and calculate your individual window prices with the configurator.
