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Kalesi general introduction of tilt & turn wooden windows
( timber windows ) and wood aluminium  windows ( timber
aluminium windows ) whether as balcony doors


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You are in the right place. Kalesi window factory is one of the window manufacturers in Estonia. For purchasing high quality windows with good price.

Call us +372 6558 515 - office in Estonia
Send email

Call us +372 5625 6225 - Eerik Kirs, manager
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The team at Aknatehas Ltd. has over 10 years’ experience in manufacturing wooden windows and doors and other wooden products. Since March 2007 our wooden and wooden-aluminium windows and balcony doors have been manufactured under the brand name Kalesi.

We manufacture single-frame tilt and turn windows and balcony doors opening to the inside because of their advantages – they are convenient to use and maintain. This type of window is the most common in Estonia and in Europe as a whole, accounting for almost 80-90% of the demand of the entire window market.

At present our product range includes the following products:
Kalesi wooden windows are characterised by the best technical and visual solutions and long-term guarantee. For the manufacturing of our windows and balcony doors we use the most advanced technical solutions and the best materials to ensure the long life-time of wooden windows in northern climate.

Our windows are impregnated with water-based Remmers
impregnating agents to protect the wood from pests and mould and for better adhesion of paint. We also use special flexible water-based breathable paints and stains for wooden windows which will not flake off the wood surface for many years.

ADVANTAGES of single-frame laminated tilt and turn opening windows and balcony doors:

  • good resistance to our climate (northern climate)
  • multiple ventilation possibilities (in the case of openable windows, micro and normal ventilation position)
  • use of ventilation possibilities 24-hour weather resistant (opening inside)
  • strong, simple and adjustable construction
  • possible to produce in different shapes and finishing
  • possibility to open in inclined as well as rotary positions (opening inside)
  • convenient to open and maintain (opening inside)
  • no gaps for accumulation of dust (simgle-frame windows)

When investing in windows, it is important to be informed!

The function of windows is not just letting the light in. Windows are also needed to ensure thermal and noise insulation and air tightness.

While in general windows are one of the construction products with the biggest thermal conductivity within the external borders of buildings, heat loss through windows is 4-6 times higher than through an external wall. Thus it makes sense to manufacture windows with maximum thermal resistance. This should be especially carefully followed in the case of large glazed surfaces. Nowadays the demand for big windows is constantly increasing, although in this case it should be considered that big glazed surfaces reduce the thermal resistance of building borders. Although in our climatic zone there are periods with reduced light, it still makes sense to design windows at the optimum size for buildings. With the reduction in heating costs we ensure as little dependence as possible on the constant price increase of heating energy in the longer term.

New windows

Windows suiting the Nordic climate of Estonia should be characterised by thermal insulation properties that are as good as possible. Provided that the windows are technologically correctly installed it is possible to reduce heat loss exiting through the building even further. In the case of a balanced and adjusted heating and ventilation system, replacement of windows will pay itself off in just a couple of years.

Windows – a solution to reduce heat loss

The most efficient way to reduce heat loss through the external borders of a building is to use energy-efficient and passive windows. Windows with good thermal insulation help to save significantly on heating costs and ensure a warm and cosy atmosphere even on very cold winter evenings. This while providing windows which do not give off waves of cold.


Windows – glazed units and performance of a selective window pane

The standard Kalesi windows are equipped with double 4 mm glazed units with one selective glass pane, where the inner pane is normally the selective glass pane. The thermal resistance values do not change if the selective glass pane is installed as an external pane of the glazed unit. In this case the light transmittance of the glass panes is slightly reduced, but at the same time solar resistance increases. The thermal conductivity value of such glazed units is U-1.4 W/m²K, provided the width of the spacer bars is 16-18 mm.

The major heat reflection capabilities of modern selective glass panes are a key issue in improving the thermal insulation of windows. One side of a selective glass pane is covered with a special transparent covering whose appearance is similar to normal bright glass. A selective glass pane reflects a lot of external cold back outside, and reflects heat back into the room. Here it should be mentioned that when using normal bright glass panes, the thermal conductivity of a glazed unit is 100% worse: the value expressed in numbers would be U-2.8 W/m²K, and windows with such glass panes do not conform to the requirements stipulated in the standard for windows EVS 837-1:2003 valid in Estonia, where the thermal conductivity of a window shall not be more than U-2.1 W/m²K.

It is good to know that by using glazed units with only one selective glass pane the thermal insulation is already improved by 100% compared to windows with normal bright glass panes.

Implementation of glazed units filled with argon or krypton gas, which is heavier than air and with better thermal insulation, ensures even better heat resistance. But unfortunately it is difficult to purchase glazed units filled with krypton gas in our region, since there are no producers who offer this more expensive solution at the moment. Today argon gas is used more because of its better price. Using argon and 16-20 mm wide spacer bars improves the thermal insulation of the glazed units even further and ensures a thermal conductivity value of U-1.1 W/m²K.

For a comparison, in a triple glazed unit filled with argon with just two 10 mm spacer beads and only one selective glass pane, the thermal conductivity is equal to the thermal conductivity of a double glazed unit provided with one selective glass pane and an 18 mm spacer bead. This is because the space filled with air or argon between two or three glass panes isolates these from one another. Optimum space between the glass panes is 16-18 mm. If the space between the glass panes is wider than 20 mm, the result does not improve because of self-cooling caused by the convection effect. The insulation properties of glazed units with spacer beads whose width is less than 15 mm are significantly reduced.

Windows – implementation of a selective glass pane in triple glazed units

With windows equipped with triple glazed units it is possible to achieve even better thermal insulation properties, provided there are two selective glass panes. Use of the second selective glass pane improves the thermal insulation of a widow even further by reducing thermal conductivity by an additional 30-35%. Use of the second selective pane will slightly reduce light transmittance, but as said earlier it gives a significant effect in heat return in the building and therefore it makes no sense to omit it.

Windows – implementation of special glass panes

To ensure personal safety, high-tempered or laminated glass panes are used. High-tempered glass panes, whose price is more favourable, can be used on the ground floor. On higher floors, where there is a risk of falling through the glass pane, it makes sense to use laminated glass panes. High-tempered glass panes are 4-5 times harder than ordinary or laminated glass panes, but when broken, small, blunt glass pieces may still cause harm, and thus in homes where windows reach the floor and there is a risk that small children may fall onto the glass panes, laminated glass panes should be preferred.

NB! Windows provided with an inner laminated glass pane provide personal safety and protection against vandalism.

To provide protection against burglary and vandalism, windows are generally provided with glazed units with glass panes with several layers of transparent PVC laminate layers or laminate glass panes, which solve the issue of personal safety at the same time.

Solar-resistant or toned glass panes are used to avoid overheating of rooms when big windows are installed on the southern and western sides of a building.

Windows – ventilation valves

If needed, windows can be provided with ventilation valves. But it is important to know that an opening milled in the window frame to install the ventilation valve reduces the thermal insulation properties of the window. At the same time, it also reduces the noise insulation properties and, also in this case, the windows do not give sufficient protection to prevent dust entering the rooms.

For the design of ventilation we recommend using solutions with closed forced ventilation (extensive heat recovery).

For ventilation purposes Kalesi windows are provided with a micro ventilation position, which enables you to open the windows approximately 5-10 mm, and also a normal ventilation position, which enables you to open the windows approximately 10 cm. Ventilation on German-type windows may be open all day, since a sudden downpour of rain cannot get in and wind does not get in to damage the window either.

Kalesi windows and balcony doors give good thermal and sound insulation!

Kalesi windows and balcony doors last for a long time!

Choose Kalesi windows and balcony doors!

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