ᐅ Trefz windows prices and user experiences?

Hello everyone,

What do you think of the following window from the company Trefz? Does anyone know it? What should we consider when choosing windows? It is intended for a new build with exterior walls made of Poroton T10 clay bricks.

Plastic window S8000 with rebate seal (exterior view)
Thanks to the classic 74 mm (3 inches) window design with 4- or 5-chamber plastic profile technology, the S8000 with rebate seal is recommended for installing double or triple insulating glass panes (Ug value 0.6 W/m²K) as well as soundproof and burglary-resistant glazing. A continuous frame and sash rebate seal ensure optimal tightness. A special feature is the weather-resistant, matte polished acrylic layer on the outside, which gives the S8000 its elegant color finish.

Best regards

That sounds like sales talk and product promotion.

If price and technical specifications matched, that would be better than this long story.

Yes, that is also the product promotion from the manufacturer.
Therefore, the question is, which technical specifications are important for windows, and what should be considered?

You’re probably especially interested in the insulation performance.

So, Ug (glass), Uf (frame), and of course the overall window value (Uw). The smaller the window, the greater the impact of the frame’s contribution.

Therefore, it’s advisable to pay particular attention to Uw.

You should also check the security rating of the windows. However: if someone wants to break in, they usually find a way. So RC 1 or 2 might be sufficient. Anything higher gets very expensive, and the surrounding conditions must also be right. What’s the point of RC4 if the window and frame can just be taken apart?

Depending on the location, sound insulation is probably also important. But there are limits here as well. The room can only be as quiet as its weakest element, whether that’s a wall, window, or possibly ventilation.

Before selecting the windows, we focused on burglary protection.

As a result, about three-quarters of manufacturers were already eliminated because they couldn’t provide or install what we wanted.

Also, as I have learned, different window sizes and the difference between casement windows and fixed glazing have varying shading effects.

So the overall calculation has to add up.

If all that fits, then you can consider design, price, and recommendations.

Simply browsing the internet is usually not enough.

What does your planner say?

toxicmolotow schrieb:
And you should check the resistance class of the windows. However: if someone wants to break in, they will. So RC1 or RC2. Anything above that gets very expensive and the surrounding conditions also have to be right. What's the use of RC4 if the entire window including the frame can just be taken apart.

Here’s something else.

We have RC3 everywhere. That means 11mm laminated safety glass, plus a bunch of mushroom-head locks (I think a patio door has 16 or 17 locking points). Lockable handles, which are fairly secure even when unlocked because they snap into place when closed.

The laminated glass makes the pane slightly darker than regular glazing, and you can notice this even without direct comparison. That’s something you just have to accept.

All the windows are screwed into the masonry with a spacing of about 20 to 25cm (8 to 10 inches) on the sides, and there are brackets attached at the top and bottom as well. This prevents the window from being pried out of the masonry in a break-in attempt.

It’s not cheap, obviously. But at least you’re not making it too easy for anyone.

Secure the doors accordingly.