Guide to windows before the energy certification of buildings

How to recognize a window. Guide windows in the real estate certification.

One of the most important aspects when we certify a property is the envelope and within it the holes. In particular, questions that we could realize… Do you know all the aspects of the windows? Do you know their typologies? Would you know how to determine a window if it is from the 50s or the 80s? ….etc. In define a series of carpentry characteristics of windows that many of us have forgotten and as professionals Technicians in the field of architecture should remember and acknowledge.

Windows on the facade. Most common typologies used:

Of course the variety is abundant and with technology Currently, new types of windows are appearing that reinvent the current ones by substantially improving all their aspects including carpentry with glass intelligent , but in a generic way we can identify:

Materials and components of a window:

Basically it is made up of glass supported by some racks made of very different materials such as steel, aluminum, wood, the PVC , polyurethane or mixed , along with any sun protection.

• If we look at aluminum profiles we will find in the market basically two distinctions:

1. Aluminum profile without bridge break thermal. Profile does not offer any resistance to the passage of the flow of heat between the exterior and interior of the space.
2. Aluminum profile with bridge break thermal . These are profiles composed of two or more metal sections joined by at least one component thermal insulation (non-metallic).

• If we focus on the profiles of PVC:

PVC is a chemical combination of carbon, hydrogen and Chlorine (More info HERE ). Their components come from crude oil and salt. HE obtained by polymerization of vinyl chloride, whose manufacturing is done from chlorine and ethylene. The PVC profiles for the manufacture of windows are obtained by extrusion and its parts are:

• Profiles of wood.

Regarding wood in the construction sector, architecture and focused on carpentry its crucial evolution has been to be able to combine it with different materials.

1. Wood aluminum mixed profiles: to the profile of wood of different dimensions, according to the need of the project, a profile of aluminium, with a multitude of possibilities and designs in function of aesthetic and constructive needs.
2. Mixed profiles wood, aluminum and insulation thermal: the incorporation of thermal insulation, EPS with high insulating performance, to the whole of the window improves thermal insulation.

• The glazing

1. Annealed glass. It is flat glass for construction obtained in fusion furnaces. He process of cooling, controlled, of the mass of glass once shaped in thickness and width that allows the relaxation of tensions avoiding breaks called glass annealing. Not to be confused with another type of heat treatment such as thermosetting or temperate.
   Annealed glass can be cut, manufactured and transformed to obtain different products of glazing. According to the procedure for obtaining the sheet of glass, we can talk about float glass or glass printed by lamination.
2. Float glass (float). The glass float consists of a glass plate manufactured by making float molten glass over a layer of tin molten. This method gives the glass a thickness uniform and a very flat surface, so it is the glass most used in construction. It is also called flat glass, however not all flat glass They are glass manufactured using the flotation system.
3. Printed glass. It is the glass obtained by lamination of the casting or molten mass in plastic state between two rollers, which subsequently cools in a controlled manner in the annealing process to its final state. Normally they are used lamination rollers for printing embossed patterns on the glass surface. For this reason, it is commonly known as patterned glass.
4. Coated glass. It is defined as a glassy substrate on which a layer is deposited, normally of a metallic nature, in order to modify one or more of its luminous properties, solar or thermal Outside this denomination are mirrors, enameled glass and glass on which a plastic film is attached to it. The glasses of layer and its classification based on its properties and possibilities of use are included in the European standard UNE-EN 1096. Glass for buildings. Coating glass.
5. Low emissivity glass. They reduce heat losses from inside the building through the glazing. Its placement can go on the sheet interior or exterior of the double glazing, without their insulation performance varies (U W/m2 K value). They are particularly effective in orientations not exposed since, apart from energy savings, they avoid the “cold wall effect” or sensation of “heat theft” that experience the human body in the presence of the cold surface of normal glazing with low outside temperature.
6. Solar Control Glass. They reduce contributions of heat produced by sunlight, decreasing the greenhouse effect. They must be placed in carpentry that can receive direct solar radiation. must be calibrated loss of heat gains in cold seasons or well complemented with low glass emissivity to reinforce insulation in winter . Inside control glasses solar high selectivity glasses stand out. HE This is the name given to those solar control glasses that allow the passage of large percentages of light. That is, they stop radiation with high energy content and without However, they allow the passage of radiation corresponding to the visible spectrum, thus making a "selection" of the wavelengths that pass through them. The selectivity is defined by the TL/g ratio, being more selective how much.

As data we can access this summary in PDF of a Congress of Glass and Frames Energetically Efficient . and we can also consult information about the advantages and types of awnings as well as their energy characteristics.

• Drawers of blind:

The thermal transmittance of the hole must be evaluated for the entire set, including the drawer shutter if it is incorporated. In the same way, air permeability, water tightness, wind resistance or acoustic insulation must evaluate the window and drawer assembly, if this is incorporated. Is In other words, the incorporation of the shutter box affects all properties that are evaluated in the window.

In the case of the thermal insulation of the complex, for the obtaining the thermal transmittance value Full window uw/sb with shutter box, it is possible to calculate it in the following way:

On the other hand, how do we remember the post… « Improvement of façade openings via CE3X «.

Carpentry in energy certification and its evolution:

We must recognize the evolution of materials to be able to determine the type of window we have in the property to certify:

Carpentry evolution of aluminium: Although it depends on each case, on In general, it can be indicated that in the 60s used series of 40mm width in the systems practicable and 55/65 mm in sliding systems. Is from the 70s when the series of aluminum sliders become 70mm. The series openings of 40/45mm without thermal bridge break maintained until the 90s when the systems appeared of RPT (about 60mm), but these systems are not generalize up to the 2000s and onwards (with systems from 45mm to 120mm).

Carpentry evolution wood:

• From traditional architecture l to the 50s: 80/90mm wooden sections are used (with 3mm monolithic glazing, seamless). examples of these carpentry are found in hotels and homes in the centers of large cities such as Madrid or Barcelona.
• In the 60s – 70s and 80s: wooden sections were used of about 45mm (with monolithic glass), these they usually present problems with the galces and absence of rubbers (permeability problems are identified in the windows built in the 70s).
• From the mid 1980s to the 1990s: windows with sections of approximately 57mm and together.
• In the 90s: mixed systems are introduced, wood-aluminum and carpentry from 68mm.
• From 2006 to the present: larger sections, from 78/88/92, and improvement in the glazing.

PVC joinery evolution:

Evolution of glazing:

After this scheme as technicians we can already recognize the qualities and typologies of a window that we can meet in the day to day of our work. Already we can identify them both in their characteristics and in the time. I highly recommend reading the Guide to windows in the certification process energetic … HERE provided by ASEFAVE (Association Company of Manufacturers of Light Facades and Windows). Where in addition to find more information than previously summarized, we can see a practical case of calculating transmittance and Other aspects that can improve our knowledge in the world of carpentry.

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Links of interest:

• Infoxication and decay of the certificate energetic
• Architecture and crisis
• Conscious recycling before the consumer.