Entrance doors · 3 min read
Are Thicker Front Doors Warmer? 68, 78 and 90 mm Compared
Greater thickness can provide room for more insulation and stronger details, but it does not determine warmth on its own. LUPOL's three timber systems also differ in glazing, locks, hinges and warranty.
LUPOL editorial team · Published: 17 July 2026
Photo: Huzaifa Mujtaba / Pexels · source and licence
In this article
01
Lignum 68 is the entry system
Lignum 68 uses a 68 mm construction. The current catalogue states Ud 1.3 W/m²K with glazing and 1.2 W/m²K without glazing, with a three-pane low-emissivity glass unit where the model is glazed.
Its standard description includes a main and additional single lock plus three adjustable 3D hinges with covers. The catalogue warranty is two years, making this the straightforward option for projects whose target matches these values.
02
Lignum Plus 78 adds insulation and multipoint locking
The 78 mm system improves the stated Ud to 1.1 W/m²K with glazing and 1.0 W/m²K without glazing. Its three-pane low-emissivity unit includes a warm-edge spacer.
The listed hardware changes to a multipoint strip lock with two cylinders and BAKA Protect 4030 3D hinges. Warranty remains two years, so the choice is driven mainly by specification rather than warranty length.
03
Eko Passiv 90 targets the highest thermal brief
Eko Passiv 90 is the thickest catalogue system at 90 mm. Its stated Ud is 0.96 W/m²K with glazing and 1.0 W/m²K without glazing; the glazed specification uses a three-pane unit with laminated VSG safety glass and a warm-edge spacer.
It includes a multipoint strip lock, two cylinders and BAKA Protect 4030 3D hinges. The stated warranty is four years, longer than the two thinner catalogue systems.
04
Why the glazed value can differ from the solid value
The complete-door Ud depends on the insulated leaf, frame, threshold and any glazing. A high-performance glass unit can make a particular glazed reference configuration test differently from a solid one; it is unsafe to infer performance from thickness alone.
Model design, size and optional equipment may affect the declared result. Request confirmation for the exact selected configuration when the energy calculation relies on a specific Ud.
05
Match the system to the building target
Choose Lignum 68 when its verified values and hardware meet the brief, Lignum Plus 78 when improved insulation and multipoint locking justify the step, and Eko Passiv 90 for the most demanding catalogue thermal target.
Installation remains decisive for every thickness. LUPOL can quote the same DW model across the available pine and oak matrices, allowing the system upgrade to be compared without changing the visual design.
The key takeaway
Thickness is useful only when connected to tested complete-door values and equipment. Compare Ud, glazing, locks, hinges and warranty, then verify the chosen model and size in the quotation.
