Thermal insulation is also one of the main functions of pvc windows. Thermal insulation properties of windows evaluated using the so-called reduced resistance to heat transfer R0pr. What is more, the better insulated windows. Simple glass conducts heat no more brickwork, but two times less than concrete and much more than the material of window boxes and binding (except aluminum); short, this is where the major heat loss. It is interesting that for the heated premises does not Single glazing is permitted. Insulation of windows increases, using two or three sheets of glass with air spaces between them of 6-20 mm. The air that fills the gap, is a good heat insulator.
To ensure set distance between the sheets of glass, pre-installed on the perimeter of a special spacer. And so that moisture can not penetrate into the air gap, the glass with a frame around the perimeter of flood special mastic (butyl). If, instead of air in the windows ‘download’ heavier, but, of course, transparent gas – for example, inert – that insulation windows can be improved by 15-20%. For each applied for this purpose the gas – krypton, argon – used its optimal bandwidth gap between sheets of glass. Heat loss through windows also reduce the deposition on the glass of a low-emission coatings; they are divided into ‘hard’ and ‘soft’ (You can find other terms: k-coverage and i-cover). It is worth noting also that because there are no gaps in the frames in the house will get a lot less dust. But the shortcomings, unfortunately, too.
First, the plastic windows miss little air. Aeration is required not only to eliminate odors and carbon dioxide, but also to create a normal room humidity, remove excess moisture. It creates the greenhouse effect and result – the moisture collects on the walls and ceiling. Therefore, the room with plastic windows should be aired frequently (3 – 4 times a day). Air permeability can be controlled using a special ventilated profile perforated flexible seal or vented slats to be installed on top of windows. The second disadvantage is that the plastic for mechanical damage is not repaired. Scratches and damage will remain there forever. Another shortcoming of plastic windows is the fact that the expansion coefficient of pvc profile is large enough, ie in the intense heat plastic window expands considerably, and in cold weather – shrinks, because of what eventually may occur cracks on the plastic. In addition, windows of plastic electrical charge and therefore attract dust.