Exterior door and energy efficiency - which door is suitable for an energy class A house?

Energy saving is one of the keywords in modern construction. An energy class A building requires solutions that ensure the lowest possible heat gain in the perimeter - this applies to walls, windows and for the first time.

The exterior door is a key component of a house's energy efficiency, as it is through the door that heat can most easily escape. Choosing the right door can help keep heating costs under control and ensure that your house meets high standards.

Why is the U-value of an external door important?

U-value shows how much heat escapes through the door.

What lower U-value, the better the heat retention.
For energy class A houses, it is recommended that the U-value of the door should be less than 1,0 W/m²K.

This means that not all doors are suitable for an energy-efficient house - you need to choose a solution that meets the thermal performance requirements.

Kaski wooden exterior doors - the best choice for energy efficiency

Kaski doors are Finnish-designed and made in the Baltics, specifically for the Nordic climate.

Thermo doors with U-value up to 0,6 W/m²K - this is an exceptionally low figure, making Kaski Thermo models the ideal solution for energy class A houses.
Structure: finger-jointed pine, combined with plywood and LVL for stability.
Soojustus: EPS or PU insulation.
Duplicates prevent wind drift.
Design: a very wide range - from classic to modern, also available in special sizes.
Glass packages: energy-efficient 3-pane argon-filled glasses.

👉 Kui sinu eesmärk on lowest energy consumption and best thermal performance, then the Kaski Thermo series is a solid choice.

Supremme metal doors - maximum security and durability

Supremme metal doors are designed with security and durability in mind.

U-value of approximately 1.0 W/m²K - which means that they are suitable for borderline Class A houses, but are not as energy efficient as Kaski Thermo models.
Metal Structure provides exceptional security and rigidity.
Thermal insulation material (e.g. mineral wool or PU) keeps the temperature in, but the focus is more on strength and resistance to burglary.
Security: metal doors are very difficult to penetrate, well suited for private houses and apartment buildings where security is a priority.
Finishing: available in wood tone, RAL and glass.

👉 Kui security and vandal resistance are a priority, Supremme metal doors are the right choice.

Kaski vs Supremme - which is suitable for an A-rated house?

Feature	Kaski Wooden Thermo Door	Supremme metal door
U-value	up to 0,6 W/m²K	approx. 1,0 W/m²K
Energy savings	Very high, suitable for a class A house	Sufficient but not maximum
Structure	Wood + LVL + insulation	Steel + insulation
Security	Very good (ASSA locks, strong hinges)	Very high (steel frame, difficult to pass)
Design range	Very wide	Wide, including metallic finishes
Resilience	Nordic climate, humidity, frost	Exceptional mechanical strength

How to make the right choice?

Measure the door opening accurately - There is no room for error in a Class A house. Our installers can always measure.
Consider energy efficiency - always ask for the U-value of the door.
Think security - whether reinforced wood is enough or you need steel.
See design - the door must match the rest of the façade.
Ask a specialist for advice - Andoora can help you select, install and ensure that your door meets the requirements of the A energy class.

Summary

When you build Energy Class A house, it is important to choose a door that meets both energy efficiency and security requirements.

Kaski Thermo wooden doors - the ideal solution if the aim is to lowest possible U-value (up to 0.6) and excellent heat retention. Plus, you get Scandinavian design and a wider choice of finishes.
Supremme metal doors - the best solution if the priority is safety and durability of metal construction, energy efficiency is good (U about 1.0), but not as low as Kask.

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