How energy saving glass works

Nowadays we have to conceive the house, office and any building from a sustainability perspective. Understanding how glass works for energy saving gives us the opportunity to make the right choice about windows and doors and to obtain two advantages:

• personal savings;
• protection for the environment.

Energy-saving glass looks like ordinary glass, but it works as a real shield. In fact, it allows the regular passage of light from the outside to the inside and the normal vision to the outside. But it guarantees indoor environments a temperature that is as close as possible to optimal, while limiting energy consumption due to the use of heating and air conditioning.

There are several solutions to prevent the passage of heat and cold. By making the right choice based on variables such as climate area, latitude, natural or artificial shade, we can benefit both in summer and in winter.

Limiting heat dispersion during the cold season and preventing excessive penetration of sunlight during the hot season is one of the ways to save and reduce CO2 consumption at home.

We will explain this mechanism to you below.

The transmittance of efficient windows

When we decide to change our windows, we must consider the transmittance of efficient glass.

This is an important factor to ensure comfortable rooms. It is strictly connected to external and internal climatic factors of the building. In fact its parameters must be established according to these variable conditions.

Not all homes require the same thermal transmittance value and the same type of glass for energy saving.

To use some technicalities, we can summarize that transmittance measures the amount of thermal power exchanged by a material per unit area and unit of temperature difference.

But let’s simplify by explaining that transmittance defines the amount of heat that passes through a material, in our case a window or door.

The symbol that identifies it is U.

Specifically, it is important to consider the role of transmittance of efficient glazing in relation to the fixtures.

In fact, efficient glazing allows domestic temperatures to be as optimal as possible, so that the house is warmer in winter and cooler in summer. In fact, they reduce heat loss by as much as 40% compared to old glass.

The best domestic comfort ensures a healthy and welcoming environment for those who live in environments protected by efficient windows.

In addition, thermal insulation affects the improvement of energy efficiency with relative advantages:

• reduction of the ignition times of the heating or air conditioning;
• elimination of internal temperature changes;
• savings on your bill.

In this way the house or the entire building becomes more sustainable.

Of course, as we have said, each house has specific thermal needs, which can be dealt with by experts in the sector, able to take into consideration the climatic and context-specific variables.

Shading coefficient

One of these variables is the shading coefficient.

It detects how much the glass protects the interior of the building from the heat produced by direct sunlight.

In fact, the glass of doors, windows, skylights and facades can amplify or minimize solar heat and, precisely, the shading coefficient indicates how much they are able to minimize the entry of heat deriving from sunlight.

It is expressed as a number between zero and one, where the lower the value, the less heat is transmitted and the greater the shading capacity.

There are several characteristics of glass that affect its ability to reduce incoming heat:

• color;
• reflectivity
• thickness.

Generally, dark-colored glasses have a higher shading coefficient than clear ones, and help keep indoor environments cooler.

Reflectivity also affects the shading coefficient. Some materials used for the coating of glass increase its reflective capacity, improuving the ability of the glass to reflect and reject heat and increasing the shading coefficient.

Thickness also affects the glass’s ability to transmit solar heat: thicker glass has a higher shading coefficient.

When these three factors come together in a single product, the shading coefficient is optimal for making fixtures intended for particularly hot and sunny climatic contexts.

Its evaluation is fundamental above all in the realization of large glass facades, for example in the case of modern buildings or shopping centers. Installing glass with a low coefficient inevitably causes a great overheating of the interior, causing an excess of Co2 emissions.

On the contrary, there are cases in which it is important that the shading coefficient is low to maintain rather high temperatures indoors, as in the case of greenhouses or swimming pools.

Design of windows for energy saving

The design of windows plays a fundamental role in the commitment for energy saving. In addition, doors and windows are increasingly playing the role of design elements, capable of giving character to the facades.

The combination of these two needs leads to the design of windows whose frame and glass for energy saving meet the requirements of:

• functionality;
• efficiency;
• aesthetics.

Projected towards these objectives, the companies specialized in the sector give great importance to the choice of materials, the type of glass and the thermal break, all conceived according to a single style that allows the window to fit perfectly into the aesthetic context to which it belongs.

The design of energy saving windows never goes beyond the goal of offering interior living comfort and optimal temperatures.

Identifying the type of windows intended for the specific climatic-geographical area and their position and orientation is essential to ensure energy efficiency, savings and to help to relieve the planet as much as possible of harmful emissions.