• Municipality Wassenaar
  • House

Windows

Are cracks closed and do you have thick curtains hanging in front of the windows, but is it still very cold at the windows? Then insulating the window itself might be a possibility. Whether this is possible with your house depends on the historical value of the frame and window, but also on the structural condition of the window. Here, too, ventilation is important to prevent moisture problems. Expert advice is very important for this.

Secondary windows inside

Existing windows can be insulated by installing a secondary window on the inside of the building. With a secondary window - a second window behind the original window (inside) – you keep the existing historical window and do not change the facade view from the outside. Installing a secondary window is a job for a professional company. After installation make sure that there is sufficient ventilation to prevent condensation between the windows. When selecting the window, make sure that it matches the existing window in terms of colour, thickness of the glass and decomposition. If necessary, discuss this with a monument advisor from your municipality. 

  • The existing window will remain intact
  • Protects against cold and increases comfort
  • Saves energy
  • Noise nuisance from outside is decreased
  • Not visible from the outside
  • This measure has aesthetic consequences on the inside
  • Pay attention to good ventilation when insulating
  • Vent the cavity between the windows with outside air to prevent condensation
  • It is advisable to consult a monument advisor of your municipality in advance
Regulations

Monumental

  • The application requires customization and is not always possible, for example in an interior of important monumental value.
  • Make sure that the space between both windows is ventilated with outside air.
  • Make sure that the detailing and window division matches the monumental window so that the rear window is not visible from the outside.

Protected city view

  • Buildings without monument status in the protected cityscape, characteristic and / or iconic buildings are subject to stricter aesthetics supervision and, according to most zoning plans, may not be changed without a permit. Make sure that the sustainability measures do not make changes. If this is the case, a permit may be required. The points of attention as stated for monuments also apply here in most cases.
Financing possibilities

Nationwide

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Tip

There are also single-glazing secondary windows with a heat-reflective coating, which hardly increases the investment costs, but provides 20% more energy savings on average!

Existing windows can be insulated by installing a secondary window on the inside of the building. With a secondary window - a second window behind the original window (inside) – you keep the existing historical window and do not change the facade view from the outside. Installing a secondary window is a job for a professional company. After installation make sure that there is sufficient ventilation to prevent condensation between the windows. When selecting the window, make sure that it matches the existing window in terms of colour, thickness of the glass and decomposition. If necessary, discuss this with a monument advisor from your municipality. 

  • The existing window will remain intact
  • Protects against cold and increases comfort
  • Saves energy
  • Noise nuisance from outside is decreased
  • Not visible from the outside
  • This measure has aesthetic consequences on the inside
  • Pay attention to good ventilation when insulating
  • Vent the cavity between the windows with outside air to prevent condensation
  • It is advisable to consult a monument advisor of your municipality in advance
Regulations

Monumental

  • The application requires customization and is not always possible, for example in an interior of important monumental value.
  • Make sure that the space between both windows is ventilated with outside air.
  • Make sure that the detailing and window division matches the monumental window so that the rear window is not visible from the outside.

Protected city view

  • Buildings without monument status in the protected cityscape, characteristic and / or iconic buildings are subject to stricter aesthetics supervision and, according to most zoning plans, may not be changed without a permit. Make sure that the sustainability measures do not make changes. If this is the case, a permit may be required. The points of attention as stated for monuments also apply here in most cases.
Financing possibilities

Nationwide

Secondary windows outside

An insulation window is an extra insulating window that is placed on the outside of the existing window. Draughts coming through gaps in the window frame can be removed by placing the insulation window on the entire window frame. This is a major improvement over single glazing. With insulation windows, cold at the window and noise from the outside are reduced. In many cases, this is only possible if the windows are not visible from the public space.

  • The existing window will remain intact
  • Not visible from the inside
  • Protects against cold and increases comfort
  • Noise nuisance from outside is decreased
  • This measure has aesthetic consequences on the outside
  • Ventilate the cavity between the windows
  • It is advisable to consult a monument advisor of your municipality in advance
Financing possibilities

Nationwide

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An insulation window is an extra insulating window that is placed on the outside of the existing window. Draughts coming through gaps in the window frame can be removed by placing the insulation window on the entire window frame. This is a major improvement over single glazing. With insulation windows, cold at the window and noise from the outside are reduced. In many cases, this is only possible if the windows are not visible from the public space.

  • The existing window will remain intact
  • Not visible from the inside
  • Protects against cold and increases comfort
  • Noise nuisance from outside is decreased
  • This measure has aesthetic consequences on the outside
  • Ventilate the cavity between the windows
  • It is advisable to consult a monument advisor of your municipality in advance
Financing possibilities

Nationwide

Thin double glazing

Does your single glazing have no historical value? If your glass does not have those characteristic bulges and is not stained glass, consider replacing single glazing with double glazing. Thin double glazing offers a solution for windows with a narrow rebate. This type of double glazing consists of two panes of glass with a narrow cavity between them. The cavity is filled with a gas that has an insulating effect, so you can tackle cold draughts and save significantly on your energy bill. The glass is available in different thicknesses, starting at 7 mm, and in many cases only requires a small adjustment in the window. The special insulating glass can be made with the appearance of old glass. If the current glass is historical or if the rebate in the window needs to be changed, apply for a permit.

  • Can also be used for windows with limited thickness
  • Often fits into existing window frames
  • Historical appearance of the window remains virtually intact inside and outside
  • Prevents cold downdraught and draught
  • Noise nuisance from outside is decreased
  • Saves energy
  • The thicker the glass, and depending on the cavity filling, the higher the insulation value.
  • Choose a variant that matches the colour, hue, flatness and reflection of the existing glass
  • Choose a type of glass with a black spacer – the edge all around and between the two glass panes.
  • Process the glass in a special sealant with the same appearance as putty. It is also possible to paint this sealant in the colour of your windows
  • Combine this measure with gap sealing
  • Pay attention to good ventilation when insulating
  • It is advisable to consult a monument advisor of your municipality in advance
Regulations

Monumental

  • Is possible when there is no culturally-historically valuable glass.
  • Is possible when the rebate of a monumental window does not need to be adjusted.
  • Placing thin insulating glass in the existing rods and profiling (i.e. window division), to replace non-historically valuable glass, is often possible after consultation.

Protected city view

  • Buildings without monument status in the protected cityscape, characteristic and / or iconic buildings are subject to stricter aesthetics supervision and, according to most zoning plans, may not be changed without a permit. Make sure that the sustainability measures do not make changes. If this is the case, a permit may be required. The points of attention as stated for monuments also apply here in most cases.
Financing possibilities

Nationwide

Continue reading Read less

Does your single glazing have no historical value? If your glass does not have those characteristic bulges and is not stained glass, consider replacing single glazing with double glazing. Thin double glazing offers a solution for windows with a narrow rebate. This type of double glazing consists of two panes of glass with a narrow cavity between them. The cavity is filled with a gas that has an insulating effect, so you can tackle cold draughts and save significantly on your energy bill. The glass is available in different thicknesses, starting at 7 mm, and in many cases only requires a small adjustment in the window. The special insulating glass can be made with the appearance of old glass. If the current glass is historical or if the rebate in the window needs to be changed, apply for a permit.

  • Can also be used for windows with limited thickness
  • Often fits into existing window frames
  • Historical appearance of the window remains virtually intact inside and outside
  • Prevents cold downdraught and draught
  • Noise nuisance from outside is decreased
  • Saves energy
  • The thicker the glass, and depending on the cavity filling, the higher the insulation value.
  • Choose a variant that matches the colour, hue, flatness and reflection of the existing glass
  • Choose a type of glass with a black spacer – the edge all around and between the two glass panes.
  • Process the glass in a special sealant with the same appearance as putty. It is also possible to paint this sealant in the colour of your windows
  • Combine this measure with gap sealing
  • Pay attention to good ventilation when insulating
  • It is advisable to consult a monument advisor of your municipality in advance
Regulations

Monumental

  • Is possible when there is no culturally-historically valuable glass.
  • Is possible when the rebate of a monumental window does not need to be adjusted.
  • Placing thin insulating glass in the existing rods and profiling (i.e. window division), to replace non-historically valuable glass, is often possible after consultation.

Protected city view

  • Buildings without monument status in the protected cityscape, characteristic and / or iconic buildings are subject to stricter aesthetics supervision and, according to most zoning plans, may not be changed without a permit. Make sure that the sustainability measures do not make changes. If this is the case, a permit may be required. The points of attention as stated for monuments also apply here in most cases.
Financing possibilities

Nationwide

Vacuum glass

Vacuum glass consists of two panes of glass with a narrow cavity between them which is vacuum drawn. The space between the panes of glass is preserved by small black spheres between the panes. The insulation value of this type of glass is very good, even better than insulated glass.
Due to its low thickness, vacuum glass often fits into existing window frames without major modifications. The weight does increase, which means that hinges or counterweights may no longer work properly in the case of sliding windows. In that case, adjust the hinges. We recommend combining vacuum glass with gap sealing. By insulating windows, the natural ventilation of your building disappears, so make sure you are properly advised about possible ventilation solutions.

  • Often fits into existing window frames
  • Can also be used for windows with limited thickness
  • Protects against cold and increases comfort
  • It is possible to achieve very good insulation value
  • Noise nuisance from outside is decreased
  • The glass can be implemented with ‘puckered’ glass which preserves the appearance of old blown glass.
  • It is advisable to consult a monument advisor of your municipality in advance
  • Reinforce counterweights of sliding windows or replace them with a modern spring system
  • The small spheres are visible
  • Combine this measure with gap sealing
  • Pay attention to good ventilation when insulating
  • This is a relatively costly investment
Financing possibilities

Nationwide

Continue reading Read less

Vacuum glass consists of two panes of glass with a narrow cavity between them which is vacuum drawn. The space between the panes of glass is preserved by small black spheres between the panes. The insulation value of this type of glass is very good, even better than insulated glass.
Due to its low thickness, vacuum glass often fits into existing window frames without major modifications. The weight does increase, which means that hinges or counterweights may no longer work properly in the case of sliding windows. In that case, adjust the hinges. We recommend combining vacuum glass with gap sealing. By insulating windows, the natural ventilation of your building disappears, so make sure you are properly advised about possible ventilation solutions.

  • Often fits into existing window frames
  • Can also be used for windows with limited thickness
  • Protects against cold and increases comfort
  • It is possible to achieve very good insulation value
  • Noise nuisance from outside is decreased
  • The glass can be implemented with ‘puckered’ glass which preserves the appearance of old blown glass.
  • It is advisable to consult a monument advisor of your municipality in advance
  • Reinforce counterweights of sliding windows or replace them with a modern spring system
  • The small spheres are visible
  • Combine this measure with gap sealing
  • Pay attention to good ventilation when insulating
  • This is a relatively costly investment
Financing possibilities

Nationwide

Insulated glass

Double insulated glass has a good insulation value. It consists of two panes of glass with a space between them filled with a noble gas that insulates. An insulating film is also applied to the glass. By replacing your existing glass with double insulated glass, you save a lot on your energy bill and take care of cold downdraught at the windows. In addition to an insulating effect, it also reduces noise pollution from outside. Double insulated glass is not always possible in historical buildings due to its thickness and weight.

  • High energy savings
  • Noise nuisance from outside is decreased
  • Makes a big difference compared to the old situation
  • Protects against cold and increases comfort
  • Usually does not fit in a historical window, unless the window (and frame) can be replaced
  • Combine this measure with gap sealing
  • Pay attention to good ventilation when insulating
  • It is advisable to consult a monument advisor of your municipality in advance
Regulations

Monumental

  • First, investigate whether there is any culturally-historically valuable glass, historic windows and frames.
  • Culturally-historically valuable glass (leaded) must be retained, but in many cases it can be provided with a special foil or an additional window.
  • Keep the original rebates and the existing window system, such as sliding windows.
  • If there is no historically valuable glass, the window or the rebate can be changed in accordance with the original window.
  • Double glass only makes sense if draft holes and cracks are closed to prevent accidental leaks.

Protected city view

  • Buildings without monument status in the protected cityscape, characteristic and / or iconic buildings are subject to stricter aesthetics supervision and, according to most zoning plans, may not be changed without a permit. Make sure that the sustainability measures do not make changes. If this is the case, a permit may be required. The points of attention as stated for monuments also apply here in most cases.
Financing possibilities

Nationwide

Continue reading Read less
Tip

There is also triple insulated glazing, which has an even higher insulation value than double insulated glass. This is more expensive compared to double insulated glazing, the higher costs are not always recouped. Triple glazing can hardly ever be used in monumental buildings.

Considerations

Insulating glass (especially double insulated glazing) can lead to the formation of condensation on uninsulated exterior walls. Proper ventilation and additional insulation measures of the building prevent this. Please consult with Monumentenzorg in advance.

Double insulated glass has a good insulation value. It consists of two panes of glass with a space between them filled with a noble gas that insulates. An insulating film is also applied to the glass. By replacing your existing glass with double insulated glass, you save a lot on your energy bill and take care of cold downdraught at the windows. In addition to an insulating effect, it also reduces noise pollution from outside. Double insulated glass is not always possible in historical buildings due to its thickness and weight.

  • High energy savings
  • Noise nuisance from outside is decreased
  • Makes a big difference compared to the old situation
  • Protects against cold and increases comfort
  • Usually does not fit in a historical window, unless the window (and frame) can be replaced
  • Combine this measure with gap sealing
  • Pay attention to good ventilation when insulating
  • It is advisable to consult a monument advisor of your municipality in advance
Regulations

Monumental

  • First, investigate whether there is any culturally-historically valuable glass, historic windows and frames.
  • Culturally-historically valuable glass (leaded) must be retained, but in many cases it can be provided with a special foil or an additional window.
  • Keep the original rebates and the existing window system, such as sliding windows.
  • If there is no historically valuable glass, the window or the rebate can be changed in accordance with the original window.
  • Double glass only makes sense if draft holes and cracks are closed to prevent accidental leaks.

Protected city view

  • Buildings without monument status in the protected cityscape, characteristic and / or iconic buildings are subject to stricter aesthetics supervision and, according to most zoning plans, may not be changed without a permit. Make sure that the sustainability measures do not make changes. If this is the case, a permit may be required. The points of attention as stated for monuments also apply here in most cases.
Financing possibilities

Nationwide

Insulating stained glass windows

A stained glass window is a special element in a historical building, but it is also a spot for major heat loss. There are various options for insulating stained glass windows. For example, you can place inside or outside secondary windows, this does not affect the stained glass. But there are two more options. In a museum setup, which is often used in churches, the stained glass window is removed from the frame, then insulating glazing is placed in the frame. The stained glass windows are placed on the inside in front of the glazing between lead strips. The last option is to place the stained glass window between two panes of glass.
For all options, the space between the new glazing and the stained glass must be well ventilated. After insulating your stained glass windows, you will notice that the cold air by your windows has disappeared.

  • Protects against cold and increases comfort
  • Saves energy
  • Noise nuisance from outside is decreased
  • Antique glass is protected against weather influences and vandalism
  • This measure has aesthetic consequences
  • Let op de ventilatie van de spouw tussen de ruiten
  • This is a relatively costly investment
  • It is advisable to consult a monument advisor of your municipality in advance
Financing possibilities

Nationwide

Continue reading Read less

A stained glass window is a special element in a historical building, but it is also a spot for major heat loss. There are various options for insulating stained glass windows. For example, you can place inside or outside secondary windows, this does not affect the stained glass. But there are two more options. In a museum setup, which is often used in churches, the stained glass window is removed from the frame, then insulating glazing is placed in the frame. The stained glass windows are placed on the inside in front of the glazing between lead strips. The last option is to place the stained glass window between two panes of glass.
For all options, the space between the new glazing and the stained glass must be well ventilated. After insulating your stained glass windows, you will notice that the cold air by your windows has disappeared.

  • Protects against cold and increases comfort
  • Saves energy
  • Noise nuisance from outside is decreased
  • Antique glass is protected against weather influences and vandalism
  • This measure has aesthetic consequences
  • Let op de ventilatie van de spouw tussen de ruiten
  • This is a relatively costly investment
  • It is advisable to consult a monument advisor of your municipality in advance
Financing possibilities

Nationwide

Solar blinds

Solar shades for your windows provides a comfortable indoor climate in the summer by keeping radiant heat from the sun outside. Solar shades on the outside keeps the heat out better in the summer than solar shades on the inside, so you don't have to cool as much, which saves energy. If solar shades on the outside is not allowed in your situation, take a look at the options for solar blinds on the inside. There are all sorts of solar blind systems on the market that differ in shape, size and colour. You can operate theblinds manually, or automatically using sensors.

  • Creates a pleasant indoor climate
  • Protects against UV radiation
  • Saves energy
  • Zonwering aan de buitenzijde van monumenten toevoegen is vergunningplichtig en is niet altijd toegestaan
  • Reflecterende materialen die aan de binnenzijde van het glas worden aangebracht, zijn vaak vergunningplichtig en niet altijd toegestaan
  • De zonwering dient bij een monument reversibel uitgevoerd te worden en geen schade toe te brengen aan het raamhout of de kozijnen
  • Plaats de zonwering aan de binnenzijde zo dicht mogelijk op het glas, om te voorkomen dat de binnenlucht alsnog opwarmt
Financing possibilities

Nationwide

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Solar shades for your windows provides a comfortable indoor climate in the summer by keeping radiant heat from the sun outside. Solar shades on the outside keeps the heat out better in the summer than solar shades on the inside, so you don't have to cool as much, which saves energy. If solar shades on the outside is not allowed in your situation, take a look at the options for solar blinds on the inside. There are all sorts of solar blind systems on the market that differ in shape, size and colour. You can operate theblinds manually, or automatically using sensors.

  • Creates a pleasant indoor climate
  • Protects against UV radiation
  • Saves energy
  • Zonwering aan de buitenzijde van monumenten toevoegen is vergunningplichtig en is niet altijd toegestaan
  • Reflecterende materialen die aan de binnenzijde van het glas worden aangebracht, zijn vaak vergunningplichtig en niet altijd toegestaan
  • De zonwering dient bij een monument reversibel uitgevoerd te worden en geen schade toe te brengen aan het raamhout of de kozijnen
  • Plaats de zonwering aan de binnenzijde zo dicht mogelijk op het glas, om te voorkomen dat de binnenlucht alsnog opwarmt
Financing possibilities

Nationwide

Tip
Historical skylights

Historical skylights

If a skylight with single glazing has been placed in your historical roof in the past, this is probably a major heat leak. Fortunately, there are now also insulated skylights with a historical appearance. Adding skylights in historical buildings is not always allowed, so always consult the municipality before installing the skylights.

Quick win
Curtains

Curtains

In cold periods it is possible to counteract draughts at the windows by placing thick curtains. Thick curtains have a strong insulating effect and therefore limit heat losses through the window. Do make sure that the curtains only hang in front of the windows and not over the radiators underneath; otherwise, the heat cannot reach the room properly.

Pleated blinds have a honeycomb structure and can be provided with an insulating film on the window side. These blinds are adjustable from below and above. Pleated blinds counteract draughts in cold periods due to the insulating effect and can serve as sun blinds in warm periods.

Quick win
Shutters and louvres

Shutters and louvres

Even in earlier times, the shutters were closed on cold or hot days to keep the indoor climate comfortable. In some historical buildings, these shutters are still present, but it is often seen as a big job to close them. Still, this can save a lot of energy.

Info
Downdraught

Downdraught

Downdraught is a cold air flow created by a cold surface at a reasonable height that ‘falls down’, as it were. This creates an uncomfortable draught flow. The solution is good window insulation with a high insulation value. You also prevent condensation on the window at a low outside temperature.