Window refurbishment

New windows provide insulation against the cold – with significant improvements on their predecessors. Up to a quarter of all heat energy in old houses is lost through the windows. Window refurbishment and replacement are therefore among the most popular measures for energy-oriented refurbishment: New windows enable the heat loss to be reduced by up to 75 percent. Moreover, they significantly improve living comfort, as their surroundings remain comfortably warm even on cold winter days. And condensation can also be consigned to the past.

Is refurbishing windows the same as insulating window glass? Compared with single glazing, today’s triple glazing offers distinctively better insulation. But how well windows insulate is not just dependent on the glass. The window frames and casements, which must also offer good thermal insulation, are just as important.

A window refurbishment or replacement only makes sense if the new windows provide good insulation. The energy label for windows rates how well a window performs in terms of energy efficiency (see also GEAK). It assigns windows to energy classes A to G. Very good windows are assigned to class A, while old, poorly insulating windows are found in classes E to G. Experts recommend targeting class A when refurbishing windows. This facilitates the best energy efficiency and the higher investment costs are offset by savings in heating costs before the end of the windows’ lifespan.

Whether you decide to refurbish windows or replace them depends among other things on your budget. A refurbishment of windows costs less than their replacement: with refurbished windows the frame of the old windows is left in the masonry and used as the base – the frame is effectively built upon. Refurbished windows can also make sense when insulating old windows in a listed building. Both the work outlay and the dust and noise caused by this are considerably less with window refurbishment than with window replacement. However, if you would like the best possible energy efficiency, slim window frames and as large a glass surface as possible, you should opt for window replacement.

The costs for window refurbishment vary greatly. They depend not only on the size and number of windows, but also their location – i.e. whether or not scaffolding needs to be erected around the house. Depending on the size and weight of the windows, a lifting platform or even a crane may be necessary. The work outlay is also a cost factor. This is lower in the case of refurbished windows than with new ones – which means that window refurbishment costs less than window replacement.

Subsidies for window refurbishment or window replacement are available in the form of funding by the building programme. However, new windows are only funded within the framework of comprehensive building refurbishment (see also façade insulation, roof insulation and cellar insulation). If you only intend to refurbish or replace the windows, you will not be entitled to any subsidy from the building programme.

If you’re having old windows refurbished or replaced, you should simultaneously replace the old blind casings, as this entails the least work and cost outlay. Old blind casings are generally not insulated and therefore the source of much energy loss. They also form thermal bridges where condensation can form in the winter, which potentially fosters the growth of mould.