Comparing wooden, plastic, and aluminum windows (plus the U value)

Last Updated on: 3rd November 2020, 11:23 pm

Wooden, Plastic, Or Aluminum Windows?

The majority of window frames is produced from the wooden glued lamels.

The wood has great insulation properties and is able to last strong temperature changes better than the majority of other materials. The durability of a quality wooden window might be as much as 80-100 years.

The plastic windows are easy to maintain and clean, on the other hand.

They also have great thermal insulating properties, anyway, due to the material limits the durability of the plastic frame is maximum of 40-50 years.

Aluminium windows are the best choice for large surfaces and for the combination of metallic and wooden profiles.

Currently, in middle Europe, plastic windows seem to be winning the battle, followed by wooden and aluminum windows.

As for the plastic windows, the market offers various double-, triple-, quadruple- profiles with various glasses, seals, knobs, and accessories.

Glass as an insulation material

The basic function of the glass is its ability to brighten the interior and fulfill the required insulating requirements. It can also significantly decrease the noise level in the interior.

For glazing, only the dithermic glasses are being used, usually, these are 2 or 3 glass plates separated by the frame.

The space between the glasses is filled with argon, krypton, or other gas mixture with a thermal insulation effect.

When designing the windows, one has to calculate the thermal conductivity. It involves the temperature loss caused by convection, conduction, and radiation.

The thermal conductivity (U) formula is as follows:

U = W/m^2K


W = amount of the heat,

m = surface of the windows (m^2 is its second square) and

K = temperature difference.

The smaller the final value is, the lower are the temperature losses (insulation keeps the inner space warmer).

The limiting U value is 1,8 W/m^2K but 1,2 W/m^2K is more recommended.

Comparison of the windows (frame) materials

Among the disadvantages of wooden windows belongs the necessity to maintain them (varnishing once in around 5-8 years) and also their high price.

Aluminum is a conductive metal and therefore it is also able to distribute temperature very well. The aluminum windows are often used for winter gardens and other large surface solutions.

The PVC or (JPV) window frames are leading the current market. Among their advantages belong their:

  • low price;
  • simple production;
  • no maintenance (but cleaning 3 times a year remains);
  • can be recycled after their life-cycle is over.

The windows regardless of what material was used can be produced in various shapes (rectangle, square, triangle, trapezoid, arch, semi-arch, or oval) and various dimensions.

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