Thermally insulated doors
That August day when the air conditioning can’t keep up. That week in January when the reception area freezes by the entrance and customers wait in a draft. Both have the same cause: the door.
When we think about temperature extremes, we first think about our comfort and the comfort of those entering the building. But insulating the entrance also has an economic and technical impact—and you only really see it on the bills.
The door: the weak point in the building envelope
When thermal insulation for a building is discussed, attention almost always goes to the walls, windows, floor, and roof. The entrance is often treated as an access element, not as part of the thermal envelope.
In reality, a significant part of the temperature exchange between indoors and outdoors happens through the door. Whether it stays open too long or has poorly insulated profiles and glazing, the door becomes the main point through which the building loses heat in winter and gains it in summer.
The effect shows up directly in gas and electricity consumption. Heating and HVAC systems work harder to maintain the same temperature, and utility costs rise accordingly. The issue isn’t a lack of equipment, but the lack of a thermal barrier at the entrance.
What makes a door truly thermally insulated
A thermally insulated door has to address two different situations: when it’s closed and when people are passing through it.
When the door is closed, construction matters. The aluminum profiles must have a thermal break so the metal doesn’t conduct cold or heat from outside to inside. The glazing must be insulating, and the seals must close off the perimeter with no gaps for air to circulate through.
When the door is in use, how it operates matters. A door that opens fully for every passage allows air exchange, no matter how well insulated it is. Here, the difference comes down to the door type, the hold-open time, and the traffic volume.
That’s why choosing a thermally insulated door starts with the question: how many people pass through this entrance each day, and how big is the temperature difference between inside and outside?
Thermally insulated automatic sliding doors
For entrances where a sliding door remains the right solution, RECORD developed the ThermCord system—an automatic sliding door built as a thermal barrier across its full height, from the operator housing down to the floor track.
The doors are made with thermally broken aluminum profiles and insulating glass, with an inert gas between the panes encapsulated in the door frame. In recent versions, the glazing is triple, and the thermal transmittance coefficient reaches 1.1 W/m²K. The seals close the door tightly and stop drafts, and the door leaves with reinforced V-shaped profiles remain stable even in strong winds, with pressure resistance of up to 1270 Pa.
The thickness difference compared to a conventional automatic sliding door is only 6 mm. The minimalist design, combining aluminum and glass, allows integration into any architectural project, including renovations, where the old door can be replaced without major façade changes.
Performance has been verified in real-world conditions. The door was tested for outdoor temperatures between -15°C and +50°C. Tests carried out for RECORD by the Rosenheim Institute in Germany showed that, when closed, its airtightness against airflow is surpassed only by sliding doors used in operating rooms. In addition to thermal insulation, the construction reduces outside noise by up to 35 dB.
The door has a recommended maximum height of 3 m and a clear opening width between 0.8 m for single doors and 3 m for double doors. The RECORD operator, with a height of up to 200 mm, supports up to 250 kg per operator. For wider openings, a telescopic version is also available, with multiple door leaves. Because the operator uses components from the standard RECORD series, maintenance remains as simple as with a regular sliding door.
Why revolving doors are the natural choice for thermal insulation
A sliding door, no matter how well insulated, opens fully with every passage. In an office building, a mall, or a hotel, that means hundreds or thousands of openings a day—and just as many moments when conditioned air escapes the building.
The revolving door works on a different principle. The door leaves rotate around a central axis, and the compartments formed between them allow people to pass through without creating a direct opening between inside and outside. The building remains closed at all times, even when the flow of people is continuous.
For thermal insulation, this has direct consequences. Heat losses in the cold season and the ingress of warm air in summer decrease, the lobby stays free of drafts, and the reception area no longer needs warm air curtains to be comfortable. In tall buildings, the revolving door also limits the stack effect—the phenomenon where the pressure difference between inside and outside pulls air through doors opened at ground level.
Revolving doors supplied by KADRA are available in 2-, 3-, or 4-leaf configurations and diameters between 1800 and 6000 mm. They can be made from tempered glass, stainless steel, brass, aluminum, or wood, in any RAL shade, and presence sensors, smooth start/stop, and special night or emergency modes ensure safe, quiet operation. Solutions like these are already in use at Globalworth Tower, Iulius Town Timișoara, Veranda Mall, and Unirii View.
Sliding or revolving: how to choose
The two solutions don’t exclude each other. A thermally insulated sliding door takes up little space, integrates discreetly into the façade, and allows easy passage for strollers, people with reduced mobility, and deliveries. A revolving door provides the best thermal separation in buildings with heavy, constant traffic and also becomes an architectural feature of the entrance.
In many projects, the optimal solution combines them: a revolving door for the main flow of people and an adjacent thermally insulated sliding door for accessibility, transporting bulky items, and evacuation. The choice depends on available space, traffic volume, evacuation requirements, and the role of the entrance in the building’s identity.
Where thermal insulation at the entrance matters most
Thermally insulated doors prove their value where the entrance is heavily used and the indoor temperature must be kept constant: office buildings and corporate headquarters, shopping centers and retail stores, hotels, hospitals and care centers, schools and universities, public buildings, airports, and train stations. In industrial and logistics spaces, the same principles apply to climate-controlled areas that connect directly to the outside.
Insulation is maintained through maintenance
A thermally insulated door keeps its performance only if airtightness remains intact. Worn seals, misaligned sensors, or a mechanism that no longer closes fully gradually reduce the benefits—without the door seeming faulty.
KADRA provides service and maintenance for automatic and revolving doors, including maintenance plans that cover seal checks, adjustments, and testing of safety systems.
The entrance is the first thing a visitor sees and the last place we think about when calculating a building’s energy consumption. A well-chosen door solves both.
Want an entrance that keeps the building at the right temperature?
The KADRA team analyzes the access point, traffic, and available space and recommends the right solution—from thermally insulated sliding doors to revolving doors. You’ll receive a tailored quote, adapted to your project.
Frequently asked questions
What is a thermally insulated door?
It’s a door designed to limit heat transfer between inside and outside. It uses thermally broken aluminum profiles, insulating glass with inert gas between panes, and seals that close the door tightly when shut.
How much can a thermally insulated door reduce energy costs?
The savings depend on the building, traffic volume, climate, and the door being replaced. The greater the temperature difference between inside and outside—and the more the entrance is used—the more noticeable the reduction in consumption.
What does a door’s U-value mean?
The U-value shows how much heat passes through the door and is measured in W/m²K. The lower the value, the better the insulation. Thermally insulated sliding doors can reach 1.1 W/m²K.
Why are revolving doors more energy-efficient than sliding doors?
Because they never create a direct opening between inside and outside. A sliding door opens fully with every passage, while a revolving door maintains separation at all times, even during use.
Can a thermally insulated door be installed in an existing building?
Yes. Thermally insulated sliding doors are only 6 mm thicker than conventional ones and can replace old doors without major façade changes. For revolving doors, installation depends on the space available at the entrance.
Do thermally insulated doors also provide sound insulation?
Yes. The insulating glass and seals reduce outside noise by up to 35 dB—an important advantage for buildings located on busy boulevards.
How much does a thermally insulated door cost?
The price depends on the door type, dimensions, finishes, and installation conditions. Fill in the contact form, and the KADRA team will send you a tailored quote.
Didn't find what you were looking for? Search below!
