Näytä suodattimet Piilota suodattimet
Why are there air bubbles or streaks inside the window glass?

The glass may have some marks created during the flat glass manufacturing process. The flat glass is not required to be optically perfect – small marks or ‘bubbles’ are acceptable as per the glass quality specification.

Detailed instructions for checking non-conformities are available from the Finnish Flat Glass Association (Tasolasiyhdistys) and in the relevant RT card (RT 38-10901, p. 5).

How to take care of self-cleaning glass?

Self-cleaning glass is regular glass that has been coated with a specialised dual-purpose coating on the outside. Organic debris on the glass is dissolved by sunlight and flushed away by rain. The coating is very securely fixed to the glass, and it can only be damaged if the glass itself is damaged by e.g. a sharp object, abrasive cleaning products or steel wool. You can wash the self-cleaning glass in the same way as our other products by using a mild alkaline detergent. If the glass is difficult to clean, the reason is usually a lack of sunlight or rain.

How to prevent the window from misting? (condensation on the internal surface of the outer frame)

Check that all locks in the internal and external frames are securely closed.

Check the settings of the ventilation system inside the property (should be negative pressure). Test the pressure as follows: Open a ventilation window slightly (by about an inch) and hold a lit lighter in front of the window. If the flame turns towards the open gap, the room has positive pressure. In this case, warm and damp air from the room gets inside the window frame through fittings or the holes of blinds. The ventilation system needs to be adjusted.

Check the seals and tightness of the internal frame. You can test them with a piece of paper. Place a strip of paper between the seal and close the window. Check the seals by pulling the paper strip. You should be able to pull it out, but the seal should be tight enough to give some resistance. Adjust the frame if necessary.

Check the tightness of the external frame and the vents in the seals which allow air to circulate inside the frame.

Check that the water holes in the aluminium profile of the bottom frame are not blocked.

How to prevent the window from misting? (condensation on the internal surface of the glass)

The condensation is probably caused by high humidity in the room and inadequate ventilation around the glass surface. Try the following:

Check that the room has adequate ventilation. If the room/window has an intake air valve, make sure that it is open.

The ideal relative humidity for indoor spaces is 35–55%.

Check that the room temperature is in the normal range (20–22°C).

Check that ventilation in front of the window is not blocked by curtains, houseplants, etc.

In a fixed window, it is common in certain conditions to have condensation especially around the edges of the glass and at the bottom. It is caused by a cold bridge that forms in the parting strips of the glass unit, which creates a cold zone in the window edges. It is also possible even if the thermal insulation capacity of the glass itself is above average. The condensation on the edges can even freeze in winter during very cold weather.

Especially in stone houses, internal humidity is higher than normal during the first few heating months, as humidity escapes the structure.

 If condensation accumulates in a fixed window, it is especially important to maintain adequate room ventilation, correct humidity levels and ventilation around the internal surface of the glass.

How to prevent the window from misting? (condensation on the external surface of the external glass)

The external surface of the window can become misted during certain times of the year when humidity is high. This condensation is caused by low indoor temperature or very good thermal insulation capacity of the window. The condensation forms on the external surface of the glass, when outdoor temperature (and outdoor dew point) rises faster than the temperature of the glass surface.

 This type of condensation is most common at dawn on clear nights. It is typically seen in autumn and spring, but it is also possible during very cold winter weather. In sub-zero temperatures, the condensation can freeze.

The condensation disappears when air temperature rises (heat dries the glass surface) or drops again (the dew point drops below the glass surface temperature, and the condensation evaporates). Condensation does not cause damage to the window. Occasional condensation on the external surface is typical in a window with very good thermal insulation capacity.

How to prevent the window from misting? (condensation inside the multiple glass unit)

If condensation forms inside the multiple glass unit, the unit is not properly sealed. If this happens within the 5-year seal guarantee, we will supply a replacement unit.

How is there dust or insects inside the window?

Two-frame windows are designed to allow ventilation inside the two frames. For that reason, the seals must have ventilation gaps to enable air to circulate. In addition, the aluminium profile of the bottom frame has water holes, which serve two purposes:

  • They channel rainwater off the aluminium strip in a controlled way
  • They ventilate the inside of the window.

The water holes are sized to enable water to run off. Plugging the water holes or ventilation gaps can damage the product and surrounding structures.

The quantity of dust and insects inside the window depends on the location and aspect of the room. In certain conditions, very fine snow can fly inside the window. However, these are not faults, as they are caused by the window’s features and the environment.

How to remove glue or other persistent stains on window glass?

The glass may have residual glue from stickers used during the manufacturing process, which is difficult to remove with regular detergents. We recommend carefully removing most of the stain with a glass scraper and cleaning off the residue with xylene, which can be purchased from e.g. paint stores. A cloth dampened with xylene can also be used to remove other types of persistent stains without damaging the glass. Wood and aluminium parts should not be wiped with xylene.

Note: Do not use mechanical removal tools (scrapers) or alkaline solvents on self-cleaning Activ glass or toughened selective glass (K glass).

How to clean a Skaala FrostFree window?

All glass surfaces of the Skaala FrostFree window can be washed in the same way as any regular glass, by using plenty of water and regular neutral (or mild alkaline) detergents or other commercially available window cleaning products.

If the window has persistent oily stains or other organic stains, acetone or xylene can be used. If these solvents are used, the window must be washed again immediately with water.

Note: Mechanical cleaning tools (e.g. glass scrapers, razor blades) should only be used if absolutely necessary and with great care.

Why do the windows make cracking or snapping noises?

When temperature changes, the external aluminium parts and joining materials heat up at different rates. Cracking or snapping noises are caused by the difference in the heat expansion properties of different materials. The phenomenon is common in spring when temperature changes rapidly. Heat expansion does not damage the window structure. The structures of Skaala products are designed to take into account heat expansion and allow the materials to “move” without getting damaged.

What causes loose fittings on windows or doors?

The loosening of fittings is normal and caused by heavy use. It can be prevented by using thread-locking compound, which is available from hardware stores and motoring shops.

Why doesn’t the external door open properly?

The most likely reason is an incorrectly adjusted door leaf. See “Adjusting the door leaf” section in the Skaala operating, installation and maintenance manual, pages 8–9.

Why doesn’t the balcony door open properly?

First check that you are opening the door correctly: the handle must be fully open (90⁰). If the problem persists, see the “Operation of external and balcony doors” section in the Skaala operating, installation and maintenance manual, page 9.

Why doesn’t the door lock?

Check whether the latch bolt is correctly aligned with the counterpiece. If it is not, check the door adjustments; see the Skaala operating, installation and maintenance manual, page 8. If you are unable to fix the fault, contact a locksmith.

What causes the dark spots on the surface of the door?

The door should be maintained regularly. Cleaning is part of the basic maintenance of the product. Dirt can harbour fungi and mould, which can damage the painted surface if it is not cleaned regularly. See the Skaala product care instructions in the operating, installation and maintenance manual, pages 12–14.


Internal door, interior door, feature door. What is the difference?

There is no difference. Since 2007, all our doors for indoor spaces have been called ‘interior doors’. Other manufacturers in Finland have followed suit. You can still ask for feature doors or internal doors, but they all mean the same thing .

What is a patio door?

Patio doors are sliding solid-glass door elements that provide access to a terrace, balcony or garden. They are often called sliding doors. At Skaala, we call them patio doors, as it describes the purpose better and communicates the way these doors connect the indoor and outdoor spaces.


What is the frame depth?

The frame depth is the width between the inner and outer edges of the door or window frame. The suitable depth depends on e.g. the thickness of the wall. We recommend checking the appropriate frame depth with a Skaala expert.

How are the door dimensions and sizes marked?

The dimensions always include the frame. Our quotes specify the exact dimensions of each standard-size door, but otherwise the dimensions are usually rounded up or down to the nearest 10cm.


 If the exact dimensions are 890 x 2,090, the size is indicated as 9×21

Note: This does not apply to custom-made doors.


How is the handle placement determined?

The handle placement is indicated for the side that opens outwards. It indicates which hand is used to open the door. If the handle is on the right edge, the door is left-handed. If the handle is on the left edge, the door is right-handed.

What does the energy rating mean?

The energy rating refers to a window’s energy consumption and associated values. It is an official rating system that is maintained and certified by Motiva Oy. The energy rating enables independent comparison of different products. It is a voluntary system for window manufacturers.

The energy rating is determined by calculating a comparison figure, which indicates the annual heating requirement of the window structure in question. The energy rating is the same scale of A–G as that used for home appliances.

The energy rating depends on the following factors:

  • the U value of the glass component
  • air-tightness
  • full transmittance of solar radiation (the g-value)
  • selective glass coatings
  • window gas fills
  • the strip material

o Source: Motiva Oy

There is currently no official rating system for door products.

The energy symbol refers to the energy rating and efficiency values of windows.


What does the E-value mean?

The E-value refers to the energy consumption of the window. For example, an E-value of 100 means that the window emits thermal energy at a rate of approximately 100 kWh per square metre in a year. The E-value is an easy way to compare different window models and manufacturers. All Skaala window models have an E-value which has been calculated based on the standardised method of VTT Technical Research Centre of Finland.

What does the U-value mean?

The U-value measures the heat loss rating. It indicates the thermal insulation capacity of the window or door. The lower the U-value, the better the insulation capacity.

What is selective glass?

A selective glass is coated with metal oxide layers that deflect long-wave thermal radiation but allow short-wave radiation to transmit through the glass. This means that solar radiation passes through the window into the room, but only some of the heat in the room is lost through thermal radiation. A selective glass unit therefore provides improved thermal insulation. It also helps to reduce condensation on the window’s internal surface during cold weather and reduces draughts, since the internal glass surface is warmer than in standard glass.


What does the 2K/3K label mean?

For fixed windows and the glass elements of external and balcony doors, the glass is often referred to as 2K or 3K. It specifies how many glass layers the unit has.

 2K = two glasses

 3K = three glasses


What is argon gas?

Argon is a colourless, odourless and flavourless gas. It is in group 18 of the periodic table. It is the most common of the noble gases and accounts for approximately 0.94% of the atmosphere. Argon is heavier than air, and it is used as an insulating gas between glass elements.