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Energy-saving Doors

Updated: Jan 30, 2023


As energy prices are on the rise and climate change continues throughout the globe, it becomes obvious that private households as well as public or industrial institutions must contribute their part to saving energy.

The construction industry in particular has a large influence on the energy footprint.

In economically developed countries the operation of buildings demands huge amounts of energy.

The lion’s share of this energy consumption is used for either heating or cooling a building in order to compensate for the loss of temperature. To help you with these issues, we will uncover in this article:

  • What are the major reasons for loss of temperature in buildings?

  • How can energy efficient doors participate in saving energy in a building?

  • What areas are most suitable for energy efficient doors?

  • How much energy can you sav by using doors such as our AL 603EEF?

What causes loss of temperature in buildings?

One of the largest factors is the transmission of cold or warm temperature through the outer walls of a building. The same effect occurs with all other parts of the outer structure, such as doors, windows or the floor.

The next big reason for increased energy consumption in building comes through thermal leaks.

These losses occur when gaps or connections are not sealed properly and air can vent through. Similar effects can also happen with leaky building materials such as building panels, windows or doors that cause warm air to either enter or leave the building.

The third cause for loss of energy is caused by wrong venting behavior or too long opening of windows or doors.

How can an energy efficient door help you safe energy?


Doors with better thermal insulation allow less transmission of cold or warm air, measured through the so-called U-value and it measure the thermal transmittance of temperatures. As a rule of thumb: the smaller your u-value, the better.

For doors these can range from 1,0 to 6,0 W/m²K, whereas smaller doors will have better numbers and thus reduce temperature transmissions.


To reduce thermal leaks in a building, doors with high air tightness can be used. A major indicator to understand how airtight a door is can be to look if the door is certified according to EN12426 or EN12427. For these certifications the door will be tested with sealed joints, whereby suction and air pressure will be used to look for potential leaks in the material. The results are then categorized in 6 different classes for airtightness, whereby the higher classes being the better. Most doors used in industrial areas such as Sectional Doors or Roll-Up Doors will rank in classes 0 to 3, for example.


Lastly, a fast and efficient opening system or partly-opening of doors can reduce the opened time for doors and thus reduce the thermal losses caused by venting.

For which areas are energy efficient doors most commonly used?

As an active element in the shell and outer hull of the building, the door plays a key role in making a building energy efficient. Most standards, guidelines, and regulations for thermal insulations of buildings such as the DIN 14092-1 for the planning of fire stations, the energy act for buildings (GEG) or OIB guidelines prescribe thermal insulation requirements for the façade of certain building categories.


The door itself as active element in the building’s façade, is given less attention. The only requirement can be a maximum U-value for a door, although it makes less sense to compare the energy efficiency of a door based solely on this single number. To make any door as energy efficient as possible, consider the following questions:

  • Is the building heated / cooled?

  • How frequently will the door be opened / closed?

  • How large is the area of the door compared to the entire façade?

If the building inside is either heated or cooled and the doors are expected to open and close with high frequency, then the thermal insulation values are less important than a fast way to open and close the door.

Energy efficient types of doors for this purpose would be high-speed doors.

While when the building is either heated or cooled and the doors are expected to open less frequently, the use of doors with high airtightness and great insulation values are recommended. In such cases the influence of U-value and thermal insulation can have a high influence on the energy efficiency of the building.

Industrial areas, workshops, garages, or critical infrastructure such as fire station and road administrations are among the categories where the right door can help save a lot of energy in the long term.

The more doors are used in a building and the higher their proportion in the overall façade of the building, the greater their impact on the efficiency.

Doors for aircraft hangars for example have a very low opening frequency, but since the doors make up a large part of the outer hull of the building, this is another area where energy efficient doors can be used with great effect.


In these situations, either Folding Doors or Sliding Folding Doors are commonly used since they can be manufactured in great lengths and heights that are necessary for this purpose. For all areas that require great insulation value and proper airtightness, we have developed our patented, energy efficient Folding Door AL603EEF.


How can our Folding Door AL603EEF help you save energy?


With our latest product development, we have set new standards for doors regarding their efficiency, design and sustainability.


energy efficient Folding Door AL 603EEF
Folding Door AL603 EEF (Energy Efficient Frame)

Our patented, thermally separated door frame combined with the thermally separated aluminum profile make sure that energy losses will be minimized.

Combined with the option of triple glazing, U-values of 1,1 can be reached, resulting in improved thermal insulation of buildings. This helps to reduce energy costs for buildings and save CO2 in the process.

Folding Door with thermally separated profile systems
Thermally separated profile systems

The high level of airtightness is achieved through the coordinated contours of the frame seals, which lead to achieving class 4 airtightness on EN 12426 standards during its tests from IFT Rosenheim.

In numbers, this would mean the door loses 3m³/m²h within a pressure of 50 Pa.

Compared with most other Roll-Up Doors or Sectional Doors, this is a very high level of airtightness to reduce temperature losses through leaks to a minimum.


Floding Door AL603EEF test for airtightness
Testing the Folding Door AL603EEF for airtightness at IFT-Rosenheim

Doors that are opened manually will usually longer remain in an opened position before they close again. Since the thereby caused ventilation is one of the major factors for loss of energy, our AL603EEF also has the capability to be closed automatically with an electric drive.

The small amount of electricity the drive uses compared to energy losses in the building due to long opening periods are minimal.

Customers also have the option to include a separate personal door in the Folding Door to allow access to and out of the building for people without opening the door itself.


Another option that is provided is partial opening.

With the right division of its wings, such as 2+4 for example (meaning there are 2 wings opening to the left and 4 to the right), the Folding Door can help to safe energy by only opening one side instead of the entire door to prevent loss of temperature inside the building.


This partial opening can be operated manually or automatically with an electric drive whereby the partial opening will be integrated into the control of the door. Partial opening can also be adjusted to a certain clear width, to allow the passing of vehicles such as forklifts or trucks to ensure energy efficient operations on site with a minimal loss of temperature for the building.


The AL603EEF is not only efficient, it also allows stunning design constructions never seen before with Folding Doors. The newly developed railing system allows full glazing for doors up to a height of 4.500mm.

The immense weight of the glass is easily taken up by the stable running rail construction.


Folding Door rail system
smooth-running rail system

Another major advantage in its design is that the mountings for the door remain invisible thanks to the innovative profile system.

Thus, there are no screws and bolts on the façade visible.


Folding Door invisible mounting
Invisible mountings

Apart from energy efficiency and the design, doors also have to be made of high quality in order to be sustainable.

The more a door breaks down, is unable to move or causes other service and maintenance problems, the more costs such a door will ultimately create for the owner.

Seemingly cheaper solutions can thus become the more expensive solution in the long term which would erase any savings made by better efficiency.

The AL603EEF with its robust materials is designed to last for decades and is therefore our best solution for sustainability across the entire products life cycle.

Summarized, here are the benefits of our energy efficient AL603EEF for you:

  • optimal thermal insulation due to separated profile system

  • exceptionally high airtightness

  • electric drive or built-in access door optional

  • large-scale glazing

  • concealed mountings

  • robust and durable

  • cost-efficient and sustainable


If you have any questions on how energy efficient doors can help you to safe costs and resources in your building, our experts are glad to help you to reduce your carbon footprint and save money in the process.

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