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In renovation, the bay block is an interesting option because it allows to install window and shutter in a single operation. Overview of the advantages of this solution, mainly proposed in PVC.

Buy PVC berry blocks

The change of windows considerably improves the thermal insulation of the house. Because depending on the type of glazing (double or triple) and the thermal coefficient of the joinery, the energy benefit can be considerable (up to 80% compared to a single glazing).

Why choose PVC joinery?

PVC dominates the window market. This is explained by its intrinsic performance (low maintenance, good thermal performance). If white is widely used, berry-block manufacturers offer many colors and plaxages (PVC profile decorative films) imitating different types of wood to better meet local architectural requirements.
This customization offers a good compromise, where the architects of buildings in France or some municipalities refuse all white PVC joinery.

Chassis: what criteria of choice

On the chassis side, the main criterion for selecting a bay block is the presence of metal reinforcements (or glass fibers) in the frame and the openings. These reinforcements contribute to the longevity of carpentry which, in this case, can be greater than 25 or even 30 years.
In the absence of metal reinforcements, the PVC profiles must withstand the stresses of the hinges (opening / closing cycles) for the frame and the weight of the glazing for the leaves. In the short term, it is the whole carpentry industry that is aging prematurely.
Anyway, it is better to be confirmed this point before choosing a model and be wary of low prices that can be an indicator. The second criterion to take into consideration is the number of chambers present both in the frame and in the openings. These latter contributing to the thermal performancee carpentry. It's really just cavities trapping air, one of the best natural insulators. The higher the number of rooms, the better the window has good thermal insulation. Not to mention the models whose main chamber is filled with polyurethane foam thus offering reinforced insulation.

Coefficients that make all the difference

Whether you put your own bay block or entrust this intervention to a craftsman, it is better to know the performance of the carpentry because in one case as in the other, it is the guarantee of have a powerful product. If the installation is carried out by a professional RGE*, it allows to benefit from the tax credit for the energy transition (CITE) and the VAT rate at 5.5 \% against 20 \% for the supply of only the carpentry.
But to take advantage of the tax advantage (CITE), you have to know how to identify the thermal transmittance (Uw) expressed in W (m2.K). It defines the performance of the chassis thermal insulation (PVC with the best performance, followed by wood and aluminum...) and glazing. The lower the value of the Uw coefficient, the higher the thermal performance of the bay block.
Inseparable from the Uw to benefit from the tax credit, the solar factor (Sw) must also offer a certain performance in parallel. This coefficient determines the capacity of the glazing to let the calories of the sun to the interior of the house. Measured between 0 and 1, the higher the value of Sw, the more heat the solar radiation enters the house.
Finally, to benefit from CITE, the carpentry must display the following performances: Uw ≤ 1.3 with a Sw ≤ 0.3 or Uw ≤ 1.7 with a Sw ≤ 0.36. As for the trunk and its shutter, they must have an additional R (thermal resistance), identifiable by a delta (Δ)> 0.22 m2K / W. Unlike the Uw, the higher the value of the R, the more the shutter and its trunk are insulating.
* RGE, recognized Grenelle of the environment.

What kind of pose?

Removal of the old carpentry

Pose in renovation (diagram 1)
If the existing window frame (usually wood) is in good condition, it can be kept as a support for the new joinery. But this thickness is added to that of the frame of the bay block not to mention the thickness of the trunk of his shutter. As a result, the glass surface is reduced to allow less light to penetrate.
Total removal (diagram 2)
The second solution is to remove the old frame to make room for the bay block. The surface of the glazing is not impacted, even if the latter is still lower than that of a conventional window in the case of a bay block, this being due to the presence of the trunk above the openings.

Metal reinforcement

Metal reinforcements in the frame

  • The presence of metal reinforcements in the frame and the openings contribute to the good resistance of the joinery and give it an increased longevity. These reinforcements also offer good resistance to vandalism...

Classic glazing or security?

The glazing of a window

Insulating double glazing consists of two or three glasses. If he has two monolithic glasses, it must be understood that the two panes are each composed of a single sheet of glass. In case of shock during a break-in, the glass bursts leaving the possibility of passing the hand inside to open the window using the handle.
The laminated double glazing (security or "burglar-proof") is designed with a monolithic glass and two glasses assembled together by a spacer PVB (Polyvinyl Butyral). The physico-chemical glass / PVB / glass bond is made by a specific autoclave treatment. PVB film has a high tear resistance. This element is important because, in case of impact, if the glass breaks, the chips remain glued to the interlayer. This barrier delays any attempt of intrusion.
Finally, if a conventional glass is generally 4/16/4 (glass thickness / air gap or argon / glass thickness in mm), the laminated glazing is recognizable by its dimension which characterizes it, namely, 44.2 / 16/4 (two 4mm glasses / 16mm air or argon blade / 4mm glass).

PVC color for its berry blocks

PVC colors

  • If white PVC is the most widespread, manufacturers also offer colors or wood decors that can customize the new joinery.

The insulating capacity of a shutter

Roller shutter

To display high thermal performance, the shutter box must have insulation (usually polystyrene). As for the deck blades that make up the shutter, whether aluminum or PVC, they must incorporate an insulating foam that contributes to the thermal performance of the bay block. The insulation of the blades provides better thermal protection when the shutter is lowered both to preserve the heat in winter than to protect it in the summer.

AEV ranking

The AEV classification indicates the resistance of the window to the elements: air, water, wind.

  • Air "A": tightness from 1 (low) to 4 (very good).
  • Water "E": tightness from 1A (very weak) to 9A (very good). For windows installed under a roof projection, only the lower part is tested and classified from 1B to 9B according to the same rating criteria.
  • Wind "V": two criteria are taken into account. The resistance to wind pressure, from 1 (weak) to 5 (strong) and the deformation of the window, from A (weak) to C (very weak). For example VA2, VB1, VC4.

Th class

The index or class Th defines the surface heat loss characteristics of the windows. It is certified by the Acotherm label and the Technical and Scientific Building Center (CSTB).
It goes from Th6 to TH17. The higher the number or the number, the better the insulation of the carpentry.

Comparative table of 8 PVC berry blocks

Comparative of 8 PVC berry blocks


Click on picture to enlarge.

PVC bay block Arts & Windows

PVC bay block Arts & Windows

Model (two leaves 120 x 125 cm): Concerto
Price*: Starting from € 1,200

  • AEV Rating: A4 E7B VA2
  • Uw Coefficient: 1.3
  • Sw Factor: 0.36
  • Th class: 12
  • Roller shutter: Inner box, PVC blades
  • Opening type: Flapping
  • Double glazing ***: 4/20/4
  • Thickness: 77/118 mm
  • Number of rooms opening / sleeping: 5/3
  • Reinforcements: Metallic
  • Warranty: 10 years
The strong points
  • the class Th

* Price incl. VAT at 20%
** Not disclosed
*** Example: 4/16/4 means 4 mm of glass, 16 mm of air or argon and 4 mm of glass

PVC bay block Brico Dépôt

PVC bay block Brico Dépôt

Model (two leaves 120 x 125 cm): Ref.: 677224
Price*: 354 €

  • AEV Rating: A3 E6B VA2
  • Coefficient Uw: 1.2
  • Sw Factor: NC **
  • Th class: NC **
  • Roller shutter: Interior trunk, insulated aluminum blades
  • Opening type: Tilt and turn
  • Double glazing ***: 4/16/4
  • Thickness of opening / frame: 70/60 mm
  • Number of rooms opening / sleeping: NC ** / 5
  • Reinforcements: Metallic optional
  • Warranty: 10 years
The strong points
  • The coefficient Uw

* Price incl. VAT at 20%
** Not disclosed
*** Example: 4/16/4 means 4 mm of glass, 16 mm of air or argon and 4 mm of glass

Castorama PVC bay block

Castorama PVC bay block

Model (two leaves 120 x 125 cm): Ref.: 654622
Price*: 400 €

  • AEV Rating: NC **
  • Coefficient Uw: 1.3
  • Sw Factor: 0,.36
  • Th class: NC **
  • Roller shutter: External box, PVC blades
  • Opening type: Tilt and turn
  • Double glazing ***: 4/16/4
  • Thickness: NC ** / 90 mm
  • Number of rooms opening / sleeping: NC ** / NC **
  • Reinforcements: Metallic
  • Warranty: 15 years

* Price incl. VAT at 20%
** Not disclosed
*** Example: 4/16/4 means 4 mm of glass, 16 mm of air or argon and 4 mm of glass

PVC bay block Franciaflex

PVC bay block Franciaflex

Model (two leaves 120 x 125 cm): Excéo
Price*: 1 490 €

  • AEV Rating: A3 E7B VA3
  • Coefficient Uw: 1.4
  • Sw Factor: 0.42
  • Th class: 11
  • Roller shutter: Inside or outside trunk, PVC blades
  • Opening type: Flapping
  • Double glazing ***: 4/20/4
  • Thickness: 80/70 mm
  • Number of rooms opening / sleeping: 6/5
  • Reinforcements: Glass fibers
  • Warranty: 10 years
* Price incl. VAT at 20%
** Not disclosed
*** Example: 4/16/4 means 4 mm of glass, 16 mm of air or argon and 4 mm of glass

Gimm PVC block block / Point P

Gimm PVC block block / Point P

Model (two leaves 120 x 125 cm): Novika
Price*: 905 €

  • AEV Rating: A3 E7B VA3
  • Uw coefficient: 1.5
  • Sw Factor: 0.45
  • Th class: 10
  • Roller shutter: External box, PVC blades
  • Opening type: Flapping
  • Double glazing ***: 4/16/4
  • Thickness: 60/60 mm
  • Number of rooms opening / sleeping: 3/3
  • Reinforcements: Metallic optional
  • Warranty: 10 years
The strong points
  • Sw factor

* Price incl. VAT at 20%
** Not disclosed
*** Example: 4/16/4 means 4 mm of glass, 16 mm of air or argon and 4 mm of glass

PVC bay block Lapeyre

PVC bay block Lapeyre

Model (two leaves 120 x 125 cm): Ref.: 2508090
Price*: 350 €

  • AEV Rating: A3 E7B VA3
  • Coefficient Uw: 1.4
  • Sw Factor: 0.34
  • Th class: 10
  • Roller shutter: Interior trunk, insulated aluminum blades
  • Opening type: Tilt and turn
  • Double glazing ***: 4/16/4
  • Thickness: 60/60 mm
  • Number of rooms opening / sleeping: 3/3
  • Reinforcements: Metallic
  • Warranty: 10 years
* Price incl. VAT at 20%
** Not disclosed
*** Example: 4/16/4 means 4 mm of glass, 16 mm of air or argon and 4 mm of glass

Leroy Merlin PVC berry block

Leroy Merlin PVC berry block

Model (two leaves 120 x 125 cm): Ref.: 73668420
Price*: 344 €

  • AEV Rating: A3 E5B VA2
  • Coefficient Uw: 1.3
  • Sw Factor: 0.30
  • Th class: NC **
  • Roller shutter: Inner box, PVC blades
  • Opening type: Flapping
  • Double glazing ***: 4/16/4
  • Thickness: 70/70 mm
  • Number of rooms opening / sleeping: 5 / NC **
  • Reinforcements: No
  • Warranty: 10 years
The strong points
  • the price
  • Sw factor

* Price incl. VAT at 20%
** Not disclosed
*** Example: 4/16/4 means 4 mm of glass, 16 mm of air or argon and 4 mm of glass

PVC window block Windows

PVC window block Windows

Model (two leaves 120 x 125 cm): PVC emotion
Price*: 1 261 €

  • AEV Rating: A3 E7B VA3
  • Coefficient Uw: 1.4
  • Sw Factor: 0.38
  • Th class: 11
  • Roller shutter: Inner box, PVC blades
  • Opening type: Tilt and turn
  • Double glazing ***: 4/20/4
  • Thickness of opening / frame: 78/71 mm
  • Number of rooms opening / sleeping: 5/5
  • Reinforcements: Metallic
  • Warranty: 20 years
The strong points
  • warranty
  • the number of closing points (10)
* Price incl. VAT at 20%
** Not disclosed
*** Example: 4/16/4 means 4 mm of glass, 16 mm of air or argon and 4 mm of glass


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