A door 54 millimeters thick: small difference, big result

Around the insulation of facades, doors play an important role. Especially when it comes to their thickness. So says Henk Breel, director of the Arnhem-based GND Garantiedeuren, the umbrella organization of leading Dutch wood door manufacturers for more than 35 years. "When you replace an existing door with a thickness of 38 millimeters with one that is 54 millimeters thick, the insulation value increases enormously and drafts are greatly reduced. And that in turn ensures a pleasant and comfortable home, lower energy bills and a substantial reduction in CO₂-reduction."

Thicker doors provide access to welcome returns. The question remains, however, exactly what needs to be met at the component level to achieve energy savings and achieve the stated 2050 climate goals. 

"In addition to a standard for the entire house, the government has also set target values when one or more individual building parts of a house are made sustainable," Breel begins his answer. "These target values indicate when a building component - for example, a door - can definitely be called future-proof. In other words, the insulation of a building component in accordance with this target value means that the building component in question is absolutely adequately insulated and, when connected to an alternative heat source, no longer needs to be modified."

Target values 

For new construction houses, the 54 mm thick door has been the standard for over 20 years. In order to comply with the stated target values when making homes more sustainable, the government has adopted this door thickness. A door must then have a minimum value of u= 1.4W/m²K, a value that is amply achieved when using a 54 mm thick door with HR⁺⁺-glass and a frame seal. "In practice, in existing homes, poorly insulating 38-mm doors are often replaced with new, moderately insulating and draft-resistant doors of the same thickness," Breel outlines. "Not a smart choice, since the limited additional cost for a 54-mm-thick door is quickly recouped and at the same time the home meets the 2050 climate goals." 

Placement 

To install a 54-mm door, modifications to the existing frame are generally not necessary. By fitting the 54-mm door with a frame profile, the gap between the door and frame can be bridged and an optimal seal is created. Only when installed in an internal situation (such as a front door), it is important to look specifically at the connection at the bottom of the door.

Insulation class 

The energy properties cannot be read from a door itself. Recently, anyone can gain insight into the insulation performance of any door manufactured by a GND member manufacturer. 

"On the hinge side of the door is a warranty and security label with a QR code on it," Breel explains. "By scanning this, you immediately see all the features of the door. 

The insulation value (see table and https://gnd.nl/thermische-isolatie/) is one of them. By adding this, we make it clear what has been applied in the house and whether it all meets the predetermined requirements. Moreover, when checked by an energy advisor, the value of the door is easily visible. This can then easily be included in the calculation of the house index."