The chambered structure of window profiles not only improves their thermoinsulating properties, but also enables them to fit inside steel bracing sections. In theory, the more chambers the better, since heat losses are lower then. However, before making the final decision it is worth asking the manufacturer or dealer for a cost calculation of windows built of profiles characterised by different

number of chambers. When considering the number of chambers, we should take into account the width of the window. In the case of five-chamber profiles, the sash width should not be less than 70 mm, while for six- chamber profiles, not less than 80 mm. These parameters guarantee optimal statics and thermo- insulating properties.

The U and K symbols indicate the overall heat-transfer coefficient - the lower its value, the better the window thermal insulation.

In spite of its numerous advantages, PVC is not a material which, in its pure form, would be able to ensure the rigidity required for proper window functioning. Therefore, it is necessary to reinforce them with sections, which are fitted inside a profile and are invisible. Sections should be made of galvanised steel sheet - with specific parameters, adequate thickness,

and properly profiled. Window reinforcements are particularly important in the case of high and wide sashes. Loads, which would have to be carried in this case by profiles without steel sections, would cause problems with window operation after some time, finally resulting in its damage.

Seals decide on the tightness of the window, and this is why their quality is so important. In a PVC joinery window seals are found both at the pane, and also where the sash meets the window frame. Their role in a sash is to separate the so-called profile wet zone from the dry zone, where hardware is most often installed. Water is removed from the wet zone through drainage holes provided in the lower, external frame section. Window seals have to be made of materials resistant to the ageing process, that is the deterioration of their properties over time. Materials used in practice include: silicones, ethylene-propylene rubber (EPDM) and thermoplastic elastomers (TPE). Seals should fully perform their role for 5-10 years. Later, if necessary, they may be replaced with new ones.

Only very high quality materials are used to a build passive and energy-saving home, characterised by excellent overall heat-transfer coefficient values. In order to reduce heat loss through divisions, buildings of this type need to have tight, laminar walls with insulation and window joinery of the best possible overall heat-transfer coefficient. Passive and energy-saving homes have to be carefully designed and located so as to obtain as much energy from the  environment as possible (primarily from solar radiation). More information on passive and energy-saving homes can be found in the publication "Low-energy  and  passive homes", available at the following link.

Window functions are determined by a mechanism, which is invisible - hardware/fittings hidden between the sash and frame. Obviously, opening, closing and tilting are the basic operations, which do not require much thinking about. On the other hand, it is worth getting to know other hardware functions, which decide about the comfort of use and safety. They may be either independent or integrated, that is occurring at the same time, and controlled by different handle settings.

Selected window hardware functions:

• blocking for the wrong handle position

The mechanism extorts the correct window operation - it makes tilting the sash impossible when the window is open. This prevents the sash from falling out of the upper hinge, which may be dangerous, especially in the case of large windows.

• clip anticreeping

A characteristic pin blocking a sash in a frame. The hardware provided with it is better secured against burglary. The clip anticreeping with special striker plates in the frame form the so-called safe points. The higher the number of these points, the safer the window.

• micro-ventilation

A mechanism allowing fresh air inflow, in spite of the window being closed. After turning the handle 45 degrees from the horizontal position, a small gap (ca. 3 mm) is formed between the frame and sash, which ensures ventilation. Owing to the special unsealing strike, the sash remains in this position until the handle is turned again. It is worth fitting windows provided with micro-ventilation in rooms with high humidity.

• window opening limiter

A window fitting may be provided with a friction brake, which keeps the sash open in the desired position. By reducing the opening angle to 90 degrees, we prevent against the uncontrolled hitting of the recess, wall, or furniture.

• stepped tilting

The MSL mechanism, which is responsible for this function, allows the tilt degree of the sash to be changed. Instead of a single position, we have several ones, depending on the needs or weather. The tilting degree is modified after turning the handle. At the same time, the window sash is protected against slamming shut.

• balcony self-latching bolt

Prevents an open balcony door hitting against the frame. After going outside - we close the door pulling special grip, and the bolt holds the door leaf. The door will open again with a slight pressure from the outside. For balconies and terraces - an ideal solution.

We provide a 5-year warranty for windows manufactured and installed by our company.

• whether the offered products have appropriate approvals and certificates
• whether the company offers warranty and out-of-warranty repairs and what are the warranty conditions
• how long the company has been operating on the market
• what the experience of the fitting team members who will be installing the windows is
• if the company may show some positive opinions regarding the fitting team?
• how long has the fitting team been operating in the current line-up
• What should we remember about when purchasing windows?
• to properly match window dimensions to the existing dimensions or planned holes;
• to have window replacement ordered to a contractor who will guarantee their proper mounting and sealing (a three-layer system is absolutely preferred);
• to make sure that the contractor has provided us with operating instructions and issued a guarantee for the completed works.

Simple cleaning agents may be used to clean PVC window joinery - it is sufficient to use a washing up detergent and a clean cloth (it is safestto use a white one). In the case of persistent soiling it is possible to use one of the commonly available cleaning preparations designed for PVC, however one should ensure that the cleaning fluid contains no solvents, "nitro" type agents, or oil-derivative substances. Acetone is particularly dangerous for PVC profiles, as it damages their surface, and in some cases it may even cause profile deformation. When selecting cleaning tools and cloths, one needs to take into account their roughness and sharpness, so as not to scratch the delicate PVC surface. Window maintenance should also include hardware lubrication and adjustment, which allows their functionality and durability to be extended in a considerable way.