As well as being aesthetically pleasing, exterior doors are also intended to fulfil a very important role. It is to retain heat inside the building. For this reason, all exterior doors have thermal insulation parameters.

At first glance, this seems complicated, which is why we have prepared 4 energy efficient packages for our customers, which simply show which thermal insulation will be ideal for your needs. You can choose any of the packages, regardless of which PORTA THERMO collection you intend to buy.

If you bet on the good thermal insulation of your home from the start, you will save money on heating in the future. Your home will be cosily warm in the winter and pleasantly cool in the summer.



You will enhance the thermal insulation of your home by purchasing an exterior door with the lowest possible heat transfer coefficient (Ud). The lower the parameter, the higher the energy efficiency of your door – which will entail significant savings on heating costs.

The most important thing to remember is this: the lower the Ud heat transfer coefficient, the higher the thermal insulation of the door. The less, the better!

The thermal insulation factor of an energy efficient door should be no more than Ud = 1.3 W/M2K. The purchase of doors that meet this parameter makes it possible to obtain funding under the Clean Air Programme.

So: which package should you choose? If you want to save a lot of money in winter – choose the PREMIUM ENERGY energy efficiency package with the lowest heat transfer coefficient.


*The Ud coefficient is given for solid doors.

The lower Ud values for the OPTIMUM, OPTIMUM ENERGY and PREMIUM ENERGY package were achieved thanks to the highly durable and thermally insulating composite construction.


Depending on the energy efficiency package, PORTA THERMO has a leaf construction frame: wooden for STANDARD or composite for the three other: OPTIMUM, OPTIMUM ENERGY, PREMIUM ENERGY.

The sheathing of all PORTA THERMO door leaves is 0.6 mm galvanised steel sheet, finished with weather-resistant PVC foil. The filling of all leaves is PUR (polyurethane) foam, which, in addition to its high thermal insulation properties, solidly bonds the entire structure.

STANDARD has a steel frame, OPTIMUM and OPTIMUM ENERGY a more robust aluminium frame, and PREMIUM ENERGY the most resistant and best thermal insulating SolidTherm composite frame.

Porta Thermo Premium Energy

Porta Thermo Optimum Energy

Porta Thermo Optimum

Porta Thermo Standard

SolidTherm composite

By using a unique composite construction, we were able to create doors with low thermal transmittance and therefore higher energy efficiency.

Our composite is a specially designed blend of ABS and fibreglass, which gives high rigidity, durability and strength to the door structure. It gives the door excellent thermal insulation while maintaining its flexibility.

Due to its high strength, this modern composite is used in automotive technology or medicine. It is a material with a so-called “”memory””. In the event of an impact, it does not deform permanently and returns to its original shape. The composite has no admixtures of biological origin, so it does not absorb water, remains highly stable and does not swell. It is a 100% recyclable material.


It may be hard to believe, but composite doors are the most eco-friendly exterior doors! Why? Composite is a blend of fibreglass and ABS that is 100% recyclable. Unlike the wooden structure, which is soaked in glue and unfortunately not recyclable.

Doors with composite construction are also 10 kg lighter than timber doors, while maintaining high strength properties.

The composite material does not absorb moisture and does not deform with temperature fluctuations. The composite also has no tendency to deform the corners of the door, as happens with wooden constructions after the door has been in use for some time. This will ensure that the door remains airtight for years to come.


When deciding on an exterior door, it is worth investing in those with the best thermal insulation performance – such as those with the PREMIUM ENERGY package. This will bring you a big reduction in heating expenses in the future. Such doors will also make your home pleasantly cool in the summer.

With a professional three-layer airtight sealing installation, the door will become a vertical thermal insulation. The resulting increased airtightness is of great importance for the construction of ecological and passive houses. It results in a reduction in your household’s carbon footprint by reducing the need for heat.

By making the right choice, you will have an impact on the climate – releasing fewer greenhouse gases into the atmosphere and contributing to reducing air pollution of your immediate environment. And, most importantly, you will save money in the long run on heating and buying better doors. PORTA THERMO is the best choice.