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Changing windows helps to improve the comfort and energy performance of the house. Materials, labels, financial aid... All to choose well its openings.

Which windows to buy in renovation?

Replacing old windows with efficient joinery offers only advantages.
The improvement of the thermal comfort, even acoustic is immediate.
Energy savings are at the rendezvous. Home security is strengthened.
In addition, the quality of the openings contributes to the added value of the house, and constitutes an additional argument in case of resale.

Windows: PVC, n° 1, wood, classic

Why choose to replace windows with PVC or wood models?

Wood carpentry

Originally used for the manufacture of joinery, wood remains very present in the individual habitat: hardwood (oak, chestnut...), softwood (fir, larch...) or exotic wood (meranti, tauari, curupixa, eucalyptus from Brazil...). The latter species are generally distinguished by their competitive price and resistance, especially in the face of bad weather and pests.
In all cases, the durability of the wood depends on the quality of the treatments applied in the factory, the exposure and the regularity of its maintenance.
Before the purchase of joinery, check the presence of the NF-FCBA mark which certifies the quality of the product.
Focus on FSC or PEFC certified wood; labels guaranteeing sustainable forest management.

PVC joinery

Another material, another style: PVC comes far ahead of its competitors, all categories combined.
Thanks to partitioned profiles in several rooms (sometimes filled with an insulator), its thermal and acoustic performances are excellent.
Metal reinforcements (which can also be synthetic) ensure its rigidity, and its relative flexibility allows it to cash in small shocks.
Finally, it is insensitive to ultraviolet rays, sea air, pollution, it requires no maintenance and its manufacture is cheap. The aesthetics of PVC windows has also evolved considerably: the profiles are thinner and the finishes more varied (up to 160 references in some brands).
To the shades in the mass is added the coextrusion which makes it possible to dissociate the internal and external aspects (bicoloration), or the lamination which consists in sticking hot a PVC decorative film on a profile.

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Windows with insulating PVC profiles

The more PVC profiles have chambers, the more insulating they are, especially when their main chamber is filled with polyurethane foam.

Aluminum to be preferred for large bays

As easy to live as PVC and enjoying the same certification, aluminum is less widespread, especially because of its high price. Both rigid and lightweight, it is best suited for large bays. It is found in almost all sliding openings.
Another highlight, its palette of colors has several hundred references (those of the RAL color chart) satin or matte - with bicoloration possible - whose durability is guaranteed by specific labels.
The profiles of dormant and opening are today equipped with thermal bridge breakers (RPT), synthetic strips that isolate the rooms in contact with the outside of those located on the housing side.

What mode of opening?


Among the different types of opening, the opening French style is the most widespread: the window has one or two leaves, which open inward. Compatible with all types of shutters, it releases the opening completely without encroaching on the outside.
Among its disadvantages, an opening to hit must be retained in case of drafts, by means of a gap; it is not suitable for large openings (beyond 1 m in width per leaf); it always encroaches on the interior space and becomes very annoying with curtains.

Tilt and turn

The tilt-and-turn opening, on the other hand, combines the advantages of the two principles: total clearance of the opening; blocking open possible, without the possibility of triggering the opening of the outside, resulting in total security at night or in case of absence. It does not distort the character of a facade. But its installation, including squaring of the opening, must be very precise for its maneuver is fluid.

Sliding opening

The sliding opening mainly concerns large windows. Its mechanism (rail + rollers) is compatible with a high weight, at least 20 kg / m²2 (glass of 4 mm in double thickness). The opening can retract behind a doubling (principle of partitioning). Especially present in contemporary architecture with mixed joinery or aluminum, they are distinguished by their insensitivity to drafts and their zero grip towards the interior. But an ordinary sliding is less airtight than an opening to hit. Hence the evolution of high-end products (in triple glazing in particular): the models "sliding to hit" or "lifting / sliding" are deported slightly upwards at the opening; the opening "in translation" are deported in turn towards the interior. In all cases, their opening (motorized or manual) is performed in one direction (the opening slides in front of a fixed glass wall).

classic window with two leaves

The classic double-leaf window is lighter thanks to its opening which covers most of the frame on the inside (the reverse on the outside). Thus, the daylight, therefore the brightness, increases.

sliding bay

Comparable in size, a three-leaf sliding doorway is more reminiscent of a carpentry than a two-leaf model. Its more traditional aesthetic is often favored in renovation.

Thermal performance: which criteria of choice?

• Evaluated in terms of heat loss for a given (heated) surface, the thermal performance of a window is defined by its overall coefficient Uw (U window). Plus its value, expressed in W / m2.K, is low, the more the carpentry is effective. Note that this coefficient itself depends on that of the frame: Uf (U frame, means frame). And more widely that of the glazing: Ug (U glass).
• The Ug coefficient of double glazing performance now reaches 1.1 W / m2.K. Which makes it possible to obtain a Uw of the order of 1.3 W / m2.K. Sufficient to meet the requirements of the BBC label (building low consumption), thermal regulation (RT) 2012 (Uw less than or equal to 1.4 W / m2.K) and the sustainable development tax credit. Lowering this coefficient is still possible with double and especially triple glazing.
• To recover calories from solar radiation when it's cold, the glass must ensure good light transmission (Tl) and therefore possess a solar factor g (ex-FS) quite high: between 0.70 and 0.80. The glazing thus allows 70 to 80% of solar radiation to pass. But beware of overheating in summer!
• Since overheating is stronger with darker sections, the regulatory texts (such as those of the tax credit, for example) take into account the solar factor of carpentry (Sw), in addition to that of the single glazing (g). Objective: to obtain a satisfactory compromise between winter and summer comfort on the facades facing south and west (summer comfort intervenes less in the east and not at all in the north).

Windows adapted to the region and the height of the house: the AEV classification

To choose a window that is well adapted to its needs, the AEV classification (air, water, wind, see below) is "refined" according to criteria relating to mechanical stresses.

They take into account (in ascending order): the region (4 in metropolitan France according to the wind speed); the zone (IV: urban or dense forest, IIIb: industrial zone, dense hedgerow, IIIa: countryside with hedges, vineyards or hedgerow - dispersed habitat, II: countryside, 0: coastal zone, lakes); finally, the total height of the building in relation to the ground (0 to 9 m, 9 to 18 m, etc.).

Windows: how to make the right choice?: make

RegionZonedAEV ranking
1-2-3IV, IIIb, IIIaA * 2 E * 4 V * A2
10A * 3 E * 4 V * A2
20A * 3 E * 5 V * A2
30A * 3 E * 5 V * A3
40A * 3 E * 6 V * A3

window with metal framing

In case of thermal insulation from the outside, the bays must be equipped with special, custom-made covers. The simplest is to opt for metal precadres assorted woodwork.

Enhanced security

choose windows for your safety

A window easily accessible from the outside must offer a certain level of security in order to delay or even deter a break-in. In PVC, it has for this purpose reinforcements (steel or synthetic) integrated in the profiles of the opening and sleeping and in which are screwed the hinges. Reinforced also, the strikes welcome pebbles shaped mushrooms or hooks. They avoid the stall of the window. The cremone handle is equipped with a key cylinder and the glazing is a laminated, burglar-proof glass.

Do or have done?

Replacing one (or more) window (s) of medium size (1.20 x 1 m for example) is within the reach of every handyman, especially if he opts for a carpentry renovation some of which are installed directly with their opening, which avoids the settings.
Be careful, however, to take measurements, since it is in all cases a customized model...
In addition, by doing the work yourself, you no longer have to rely on the benefits of the tax credit, whose rate has recently been revised upwards. A point to study well...

The opinion of the expert *

"The immediate gain in terms of comfort and cost savings means that the replacement of windows is at the top of the renovation work, but the performance is matched only by the quality products placed in the This is not obvious, because many non-specialists, for example, tend to overestimate the state of their sleepers... "
* Jean-Pierre Loustau, president of the firm TBC, specialized in technical studies of the building.

a bay block

In renovation, the bay blocks replace the windows equipped with shutters. Combining carpentry and roller shutter, often motorized, they save in comfort of use. But the trunk surface decreases daylight.

set up a renovation window

The installation of a renovation window avoids the total removal of the old joinery.
Its leaves replace the original ones and the new frame covers the old, usually wooden.

Labels, brands and certifications to know

NF PVC and aluminum RPT windows and blocks

Managed by the Cstb, this certification guarantees the constancy of the level of production quality of joinery, as soon as the manufacture of their components. Extruded PVC profiles must therefore benefit from the NF 126 mark which certifies the conformity of their extrusion. The RPT aluminum profiles (with thermal break) must comply with the NF EN 14024 standard and the NF 252 certification rules. The insulating glass units must be certified (Cekal for example) and the NF EN 1670 approved hardware.


The brand uses, among other things, the values ​​of indices and classes of the Acotherm label to certify the level of performance of wood joinery. Other criteria are also involved: the quality of the glazing and its implementation, the endurance in opening and closing, the resistance of the finish... For more information:

Complementary to NF marks, this label certifies the acoustic and thermal performance of joinery with their glazing. Four classes are defined by a sound reduction index (RA, tr) for road traffic noise: from AC1 ≥ 28 dB to AC4 ≥ 40 dB (from the lowest to the best acoustic performance). ). In addition, each level of thermal insulation (Th 6 to 17) is a coefficient Uw for windows, French windows and roof windows, and Ubb, jn. for the bay blocks (joineries equipped in factory with a shutter). From U ≤ 2.6 up to U ≤ 0.8 W / m2.K. The label is awarded by the Cstb (Scientific and Technical Center for Building), the Ginger CEBTP and the FCBA Technological Institute after a voluntary certification process.
AEV ranking
At the request of the manufacturers, the windows are also classified according to three criteria: their permeability to water (A * 1 to A * 4 according to the NF EN 12 207 standard); their watertightness (E * 2B to E * 8B according to standard NF EN 12 208); their wind resistance (V * A1 to V * C3 according to standard NF EN 12 210).
VEMCROS ranking
It is added to the AEV classification and only concerns the performance of PVC and aluminum berry blocks. It reads: V (wind resistance), E (endurance), M (maneuver), C (impact resistance), R (sunshine behavior), O (occultation) and S (corrosion).
It concerns the surface preparation of aluminum profiles before lacquering, with a view to their installation on the seaside. Like the two following labels, it is awarded by the Association for the development of anodized or lacquered aluminum (Adal).
It testifies to the quality of the powder coating process of the aluminum: consistent thickness of the finish, adhesion, impact resistance, etc. Qualanod It certifies the quality of anodized finishes: appearance and color, thickness, resistance to abrasion, light, salt spray...

Financial aid in 5 points

• Which coefficients?

To be eligible for the Sustainable Development Tax Credit (SDTC), windows and French windows must have a Uw coefficient less than or equal to 1.3 W / m2.K and a Sw greater than or equal to 0.30. Or a Uw ≤ 1.7 W / m2.K and a Sw ≥ 0.36. Roof windows must have a Uw ≤ 1,5 W / m2.K and a Sw ≤ 0.36.

• What conditions?

The installation must be performed by a recognized environmental professional (RGE). The amount of work (excluding labor) remains subject to the following limits: € 8,000 for a single, divorced, widowed or widowed; 16 000 € for a married or pacsé couple, plus 400 € per dependent. Under means conditions (reference tax income: € 24,043 for one person, € 34,081 for a couple).

• What rate for what work?

The Minister of Ecology has announced (as we are closing these pages) a reform of the CIDD from 1 September 2014, with a single rate of 30% (instead of 15 or 25%) without obligation to achieve a bunch of works.

• Which accumulation?
The CIDD can be cumulated unconditionally with the VAT at 5.5%. But to combine it with the zero-rate eco-loan (E-PTZ), the tax income must not exceed € 25,000 for a single person and € 35,000 for a couple (plus € 7,500 per dependent).
• For more info finance-my-project / renovation / credit-dimpot-sustainabledevelopment.
renovation-info-service. to find a professional RGE.

Video Instruction: Energy efficient windows - Make the right choice of glazing