Find the answer to the most frequently asked questions below

Is there the option of extra burglar protection on windows?

All Kastrup products have a basic burglar-resistant package. In addition to the basic security package, you have the option of an expanded security package, which, with measures like security-glued glass, includes further enhanced security.

If you need further burglary protection you can choose the PAS24 security package. Our KASTRUP ENERGY and INVI windows as well as a wide range of our front doors and panelled doors are tested and certified for PAS24. Regardless of the individual security packages, you can always buy exactly the security component you want, for example:

Where can I view Kastrup’s windows and doors?

Most of our distribution partners in the UK and Ireland display our products in their showrooms. Find your nearest distribution partner here.

Why can I see finger joints through the wood?

To achieve the best quality, the wood is scanned for knots, cracks and resin exudations, which are then cut off. This means that, to great extent, we prevent large brown blotches from knots and resin seepage. When the wood is cut up, it is glued with finger joints for planks. This ensures a good product, which is virtually knot-free, and provides stability of shape. The finger joints also enhance the wood’s tensile strength. The darker the paint on the wood, the more visible the finger joints will be. This is because dark colours have a higher proportion of pigment, which makes even matt colours appear glossier, so any irregularities in the wood become more visible.

Why does misting occur between the panes of glass?

Misting between the panes indicates that there is a leak in the pane. The puncture on the pane impairs the insulating properties of the glass, so the glass should be replaced.

Why does misting occur on the outside of my new windows?

Mist may occur on the outside of windows for short periods of time. This is not due to defective glazing – far from it. It is the natural consequence of the superior insulating capacity of energy windows.

Mist occurs especially when the outside temperature drops, and we turn up the heating inside. The high insulating properties of your windows prevent the heat indoors from getting to the outer pane, which is cooled down. During the day, when the air outside gets warmer, but the outer pane is still cold, heat and cold meet. This causes the windows to mist up.

You can witness the same phenomenon in nature on grass and leaves. A window never gets harmed by this temporary mist effect.


Why do misting and condensation occur on the inside of my windows?

Condensation is water deposit and forms when warm, moist air comes into contact with a cold surface. Hot air can hold significantly more water than cold air can and, if hot air cools (e.g. on a pane), the excess water in the air will condense on the object.

Although the development of new windows means that the windows have become considerably warmer, the glass surfaces are still the coldest surfaces in a room. When the humid, warm indoor air (e.g. in a kitchen or bathroom) hits the glass surface, the air cools and condensation forms.

The first places on the glass for condensation to form are always along the edges. This is because the panes are built together using a spacer, which is thermally the weakest part of the glass.

Kastrup Windows uses Swisspacer Advance, which is made of tempered plastic and stainless steel and does not conduct heat and cold. That means that not only do you save on heat, you also avoid irritating condensation along the edges of the glass as much as possible.

To avoid condensation, you need to dispel moisture from your home. You can reduce condensation by:

  • Ventilating regularly
  • As far as possible, avoiding hanging laundry to dry inside your home
  • Using the extractor fan when showering or taking a bath. If you do not have an extractor fan, immediately air the bathroom after each shower or bath.
  • Opening 2-3 windows in the ventilation position or having fresh-air trickle vents fitted in windows to stay open all day.
  • Making sure the air circulates around the home. Limit the number of houseplants on windowsills.

Poor, humid indoor climate can affect your health and destroy windows. Condensation running from the panes onto a window’s wood can cause mould growth and the wood will start to rot.

How important are trickle vents for a window?

The need for trickle vents depends on the size and function of the room. Especially in rooms such as bathrooms and utility rooms, where we wash and dry clothes, it may be a good idea to get windows with trickle vents. In buildings with mechanical ventilation systems, trickle vents are not usually required.

Trickle vents do not provide ventilation itself, but, as their name suggests, supply fresh air and help improve a home’s indoor climate. Kastrup’s trickle vents have a flow section of up to 40cm3.

Why is water coming in through my windows?

If water is coming in through closed windows, it may be that the hinges or strike plate needs adjustment. You should also check that the seals are in their proper place and drainage holes are not blocked.

How do I maintain my wood/aluminium windows?

The outside of wood/aluminium windows are covered with weather-resistant aluminium profiles. As standard, Kastrup uses a so-called FIJI surface, which is more resistant to scratches than the most widely used aluminium surfaces in the industry. The exterior aluminium profiles should not be painted but should be washed a few times a year with soap and water or a soft brush. The interior wood parts are not exposed to wind and weather and do not in principle require paint. Nevertheless, it is important to maintain the interior wood so that it can withstand moisture and rain when the window is open.

There is no risk of rot or fungus on our composite profile in the frame rabbet. We recommend cleaning the composite profiles with a cloth and soapy water a few times a year.

In addition, we recommend oiling all moving parts and inspecting sealing strips and glass tape once a year.

How do I maintain my hardwood sashes?

Your new KASTRUP ENERGY windows with an oak or mahogany sash are primed with a clear oil at the factory. It has a high penetration property and contains fungicide to protect against mould and fungus. Oak windows and doors must be treated with Træ-Nolin 35 oil from Træ-Nord A/S, while mahogany windows and doors must be treated with Akzo Nobel Aqua Oil 1-2 times immediately after fitting.

It is important to maintain the wood regularly at least once or twice a year: especially elements fitted facing south and east where the sun is strongest. As a general rule of thumb, when water no longer beads on the wood, it is time to oil.

If the wood is grey or discoloured, it helps to lightly sand prior to oiling. Before oiling, it is important to clean the wood with a cleaning agent and remove abrasive dust, otherwise it will prevent the oil from penetrating the wood.