Replacing windows can achieve a quarter of the savings targets

After the attic and the walls, the insulation of the doors and windows should be a priority during works for the thermal improvement of housing. According to the study of energy efficiency conducted by Pouget Consultants for the account of the Pole for the Window of the FFB, the replacement of old windows with high-performance products leads to a substantial reduction of heating needs.
It is recognized that the openings (doors and windows) are at the origin of 10 to 15 % heat loss of a building, after the roof and walls. However, the replacement of single glazed windows by windows modern, increase of how much higher the performance of the dwellings. It is, in any case, that concludes Adeline Junker, study manager for Pouget Consultants, which has simulated the replacement of windows and shutters in residential buildings – individual homes or collective housing, in order to observe the effects on the heating needs and energy consumption.
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The results of these simulations, conducted on four multifamily buildings and three houses, and no or little isolated, and with glass surfaces, and different orientations, show that this simple replacement windows can reduce heating requirements by a quarter. In terms of energy savings, it is 60 kWh/m2/year, it will be possible to save money, “more than 25 % of the improvement to an energy-efficient renovation of which the objective is to move consumption from 300 to 80 kWh/m2/year“, argues the document.


Gains encrypted or simply noticeable
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The numbers vary depending on the building type and climate zone. In the collective dwelling dating prior to 1974, the replacement of old windows (Uw = 5,7) by contemporary products (Uw = 1,3) can reduce the need for heating from 24 to 27 %, or 40 to 60 kWh/m2/year. The gain on the energy consumption of the five uses regulatory is established at 18 %. For a detached house prior to 1974, the results are less impressive, since the heating requirements are reduced from 10% to 13%, corresponding to gains of a little more than 25 kWh/m2/year (about 10 % of consumption regulatory of a house). It is in the mediterranean region (climate zone H3) that these improvements are the most sensitive, probably because the envelope is less well isolated than in the colder regions. The study notes : “By adding the replacement of components, the gain is improved by about 4 kWh/m2/year“. An insignificant decrease of heating needs (-1 %), offset by the improvement of the summer comfort.


Professionals in the carpentry and note that windows are “the only active element of the built environment” which, in addition to contributing to the thermal insulation, “capture solar heat and natural light” and contribute “to the renewal of the air“. They emphasize the benefits in terms of comfort of indoor living and ease of the work, made in site, which was occupied in just a few days. “It is totally justified as the replacement of the exterior woodwork (windows, external doors and shutters) (…) to be eligible to the QUOTE, to the Eco-PTZ, as well as to the aid offered by the local communities“, they argue. The Pole Window the FFB concludes on the need to have it installed by businesses EGR products, whose quality of design and manufacturing is demonstrated, in order to ensure the performance and durability.

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