● How do I calculate the energy efficiency of a windows?

To verify the actual insulation of a window we use an insulation coefficient called Uw.

This coefficient is determined by a calculation that varies depending on the size, type of window and another calculation depending on the cornice of the frame (value called Uf) and the glass insulation value (value called Ug).

According to the above mentioned factors you can determines the Uw coefficient, which is inversely proportional (the lower the number is, the more insulating the window will be).

For this calculation you should also consider the coefficient of insulation of the glass channel (coefficient is called PSI) that also varies according to the type of glass channel.

● What is the Uf coefficient?

Every window has a frame around the glass.

Depending on the type of material, the size and the thickness this value varies.

Wood (especially soft wood) has a high insulating power therefore a wooden window, together with good glazing is certainly an excellent choice for the insulation of your house.

● Why “g” factor is important to consider the type of glass used?

When choosing glass almost everyone focuses on the Ug coefficient, which is the coefficient of insulation of the window but few people take into account the g factor.

The g factor indicates the average percentage of energy that penetrates into the room through the window.

This value has to be chosen according to the exposure of the glass itself, the type of climate in the area where the window will be installed and the eventual presence or absence of shutters outside the building.

The lower the g factor is the less heat will penetrate from the window.

In the case of solar shielding the experts also calculate the got, which is considers the coefficient of the glass itself combined with the shutter. We should therefore assess the proper heat balance with a heating engineer, in order to choose a good glass.

● Which role does the window play in the insulation of a building?

Nowadays windows are increasingly considered a sort of transparent wall that helps to optimize the overall value of the façade, in combination with normal walls (masonry).

Windows should be considered multifunctional and multi performance “systems” where not only the insulation coefficient of the window itself is important, but also watertight, airtight together with acoustic insulation coefficient.

Normally the project manager determines the minimum performance values of the windows, considering the surface and the ratio between non-transparent walls and normal walls.

An example:

when the building has a very high thermal and acoustic insulation and glass walls are very small, compared with the façade, we will only need lower performance coefficients for the window.

On the other hand, in the case of big glass walls, the role of the window will be decisive.

● How can we get high acoustic insulation?

Acoustic insulation is a matter that is more and more present in the choice of windows.

Our contemporary way of life is certainly more stressful than it used to be in the past, and leads us to be more sensitive to noises, especially when you live in a town with a lot of traffic that is an acoustic nuisance, especially at night.

The choice of the window here plays a decisive role, glass construction technology now provides the most efficient and suitable kind of glass, in order to prevent us from external noises.

However we have to consider the type of windows system in its sealing perimeter frame around the glass.

If you buy double or triple sealing windows you will certainly prevent air filtration and noise within the perimeter of the window, furthermore a manufactured window guarantees that the locking tolerances of the gaskets are correctly performed. In fact the manufacturing with numerical control machines guarantees the perfect construction windows.

You don’t need to be a good carpenter to produce good windows, you have to be technologically advanced.

● When do you need the “Warm Edge” glass channel called “Hot” glass channel?

The lath that separates the two thermal glasses was improved through the years.

In very cold climates in winter, in case of strong temperature difference between the inside and outside temperature, mould might originate in the lower part of the glass.

This is because the coldest part of the glass is the perimeter of the glass channel that is normally made of aluminium and called “cold” glass channel.

Since several years there has been a glass channel called “Warm Edge” that is thermally insulated and made of thermoplastic material that is recommended also in case of cold climates with temperatures reaching values close to zero degrees.

● Why tilt and turn windows?

New houses are much more insulated than those of 20 years ago, also during daylight hours are on average less inhabited than once.

We usually keep windows closed when we’re not at home, and keep them closed also in the evening when we return home to prevent cool or heat and use of air conditioning in summer. This generates humidity. In fact when we cook we generate steam, when we take a shower we generate steam, when we leave the towels on the radiator in the evening to let them dry we generate steam. In addition we maintain toxic gases inside the buildings and this is pretty polluting.

New generation windows make airtight, as it should be.

The tilt and turn allows a gradual and controlled opening of the window, without changing the temperature inside the house. All Eurolegno tilt and turn window have “micro ventilation” system, to minimize heat loss and to allow continuous air circulation, so important for our health, inside the house.

● Why is insulation important when you choose windows?

Windows play a key role in the thermal insulation of buildings.

From an average assessment we can state that windows contribute up to 25% in the general insulation of a building.

Other elements such as the roof, the type of heating and the insulation of the walls do the rest.

However, you don’t need to exceed, when you choose always evaluate the costs and benefits.

An example: if you have a very dated structure that does not have a high insulation coefficient, you don’t need to install a triple glazing window with very low thermal transmittance if you don’t deal with the transmission that comes from the roof, floor and then from the walls.

● What is the role of the subframe?

The subframe is an element that is normally installed in the wall before the window.

It has several functions:

The first is the preparation of the wall where the window will be placed, so that the frame can be installed as soon as the masonry works such as plastering, installation of thresholds and painting are done.

The second function is the preparation for building the window and its accessories such as mosquito nets, shutters (sunshade, curtains, roller shutters) in the wall.

The design, the check of proper installation and the building of the subframe into the wall are basic for a correct final result.

All Eurolegno partners can design, recommend products and follow all the above steps.

● How are windows installed?

Obviously there are many ways and many different materials you can use when you install a window.

Certainly the biggest risk is to buy high performing windows and then nullify everything though inadequate installation.

Specialized staff and high quality materials are basic to provide an efficient and guaranteed installation.

All Eurolegno partners perform installations with high qualified staff that guarantees a correct installation and a final result that complies with the “Certified Installation”.