Useful tips

Which joinery to choose

Aluminium or PVC is a matter of personal preference. About polyvinyl chloride (the base material for PVC joinery) you should know that it is a polymer material and, like every polymer, ages over time — but in return it is a very good thermal insulator. Serious profile manufacturers keep developing their technologies, adding advanced modern modifiers that extend service life and reduce the change in appearance over time. They monitor consistent quality at every stage — from the composition of the raw material to the extrusion of the PVC profiles. That is why we repeatedly stress that the origin of the profiles is the first step that guarantees reliability and a long life for the windows. It should be noted that the higher the number of chambers, the better the thermal insulation. Unfortunately, the higher the number of chambers, the higher the price of the window too. It is also important to bear in mind that insulating windows are only part of a complex set of measures related to thermal insulation.

As for aluminium, it is a metal that does not oxidise, retains its strength properties and practically does not age. On the other hand, aluminium is a good conductor of heat, which means that for making windows in our climate it is advisable — when it comes to a home or office — for the aluminium profile to have a thermal break. These are plastic inserts that divide the profile into two parts, thereby separating the interior from the exterior space. The width of the thermal bridge is essential for good results. Here, however, we must remind you that profiles with a thermal break are more expensive.

How to clean the joinery

When it gets dirty, we are usually forced to find the right cleaner for the job. Clients often ask us which products to use. Aluminium and PVC joinery have a special coating that protects them from scratches and they can be cleaned easily, as long as the lacquer coating is not damaged. We must be careful that the products we use do not corrode this protective layer. There are specially made joinery cleaners, which you can buy at our offices and showrooms. The universal and affordable option is petrol (benzine) — with a cotton pad soaked in it, all stains on your joinery are removed.

Moisture in the living space

There are very few areas in and around the home about which so much wrong has been written and so much discussed as the ventilation of living spaces. Are our window structures too tight? Are we suffocating in over-sealed homes? Or are we throwing away too much heating energy through unsealed windows? Why don't the experts give unambiguous recommendations? Or do the laws of physics not allow such recommendations? Questions upon questions that demand clear answers.

Living spaces are constantly being moistened. This happens through:

• Moisture from new construction
• Water vapour produced by household activities
• Moisture released by people and animals
• Water running off in wet rooms (e.g. bathroom, kitchen, laundry room)
• Water used for cleaning
• Moisture on the surface or inside building elements (from condensation of water vapour)

The following table shows the approximate amounts of moisture released in the rooms:

In line with the laws of physics, moisture release leads to the formation of moisture on the walls (condensation). The causes of such moisture appearing are:

• Insufficient ventilation of the rooms;
• Insufficient thermal insulation of the external walls;
• Structurally determined building defects;
• Incorrect heating — unfavourable placement of the heat sources;
• Inappropriate actions, e.g. wrongly used intermittent heating mode;

Excessively high and prolonged humidity manifests itself through the following unpleasant phenomena:

• In the corners and especially behind furniture, damp patches appear on the walls, which after some time become covered with mould;
• The windows in the bathroom, kitchen and bedroom fog up;
• The walls below the windows become damp.

Relative humidity

The warmer the air, the more moisture it can hold. The opposite is also true — the colder the air, the less moisture it can hold.

Let's give an example: 1 m³ of air warmed to 20° C can hold at most 17.5 g of water in gaseous form. The same amount of air at 0° C can hold only 5 g of water. In practice this means the following: when 1 m³ of humid air (100% relative humidity) is cooled from 20° C to 5° C, then 12.5 g of water condenses into droplets.

Cold air is always “dry air”! Again and again in late autumn, at temperatures near 0° C and very high relative humidity, one hears that windows should not be opened so as not to bring moisture into the house. This opinion is wrong. From the example above it is clear that at 0° C and 90% relative humidity the air has taken up only 4 g/m³ of water. If this air is warmed to 20° C, it can take up another (17.5 − 4) = 13.5 g of water until 100% saturation. For our everyday practice this means that excessive humidity in living spaces can only be removed through effective ventilation.

Heating and ventilation

Incorrectly placed heating, together with insufficient ventilation, can be the main cause of moisture damage.

Unfortunately, the term “intermittent” (short-term) heating still refers to a method in which rooms are heated only when they are in use. When leaving the home in the morning, the heating is left at a minimum (frost protection). On returning in the evening, the heating is turned up. The surface temperatures of the walls under such an approach are always very low. When warm air reaches such walls, the appearance of moisture on them — and also on the windows — is favoured.

Anyone who wants to use their heating sensibly should keep even rarely used rooms at an average temperature of 16 – 17° C.

Corners and recesses that cannot be reached by warm circulating air are especially prone to moisture forming on the walls. One of the causes of moisture forming around the windows is insufficient airflow over the windows.

Tasks of ventilation

Gases, odours, moisture and harmful substances determine not only physical well-being but, in extreme situations, lead to damage to human health. The task of ventilation is therefore:

• To ensure air quality for a healthy indoor climate;
• To prevent the formation of moisture and mould through sufficient air circulation;
• Where there are open fireplaces (e.g. a fireplace), to ensure a sufficient amount of air.

Ventilation options

From a hygiene point of view, an amount of fresh air of 10 – 25 m³ per person per hour is foreseen. This means that for a living room with an area of 30 m² and a height of 2.5 m (i.e. 75 m³), in which there are 3 people who need fresh air of about 60 m³/hour, the air must be changed 0.8 times per hour. Since this air exchange cannot be achieved through closed windows, targeted ventilation measures are taken.

Burst (shock) ventilation

With this method of ventilation, the window sashes are opened fully for about 10 minutes to ensure a complete exchange of air. This quick way of ventilating makes sense, because the walls, carpets and furniture retain their temperature. These surfaces do not need to be reheated. The air in the room warms up again in a relatively short time.

What is so-called K-glass

The other name by which it is known is low-emissivity glass. It is float, transparent glass with a crystal-white reflective tint and high solar and thermal protection. When built into an insulating glass unit, it raises the thermal insulation of the unit and brings it close to that of the PVC profile, so that no condensation forms on the glass itself. They are treated on one side with a metal oxide (titanium coating). The layer is resistant to mechanical and chemical treatment. Manufacturers guarantee that the titanium emulsions and their derivatives do not react to weather conditions and do not change their transparency or colour. Titanium is from the group of noble metals, and extreme conditions are needed to change its properties (for example: a vacuum environment plus a temperature above 700 degrees).

K-glass turns short rays into long ones and returns the heat to the room you are heating. It lets through one part of the solar radiation (UV /from 280 – 380 nm/ — 3%; visible part /from 380 – 780 nm/ — 44%; IR /from 780 – 2500 nm/ — 53%), reflects a second part, and absorbs a third part. The glass does not let through rays above 2500 nm. The rays from heating appliances are above 10,000 nm. The glass does not let them through but absorbs a certain part, which is why the air in the glass unit must be drawn out and filled with gas — Argon, Krypton or Xenon (so that the glass does not break from the stress).

To sum up in two sentences: K-glass has better insulation properties (an alternative is triple glazing); its insulation properties in a glass unit range from 1.4 W/m² K to 1.8 W/m² K. Let us recall that it is not a radical solution to the problem of moisture in the room.