Double glazing was not used as a standard until the 1980s. As a result, many older homes still have single glazing. Single glass causes a lot of heat loss and thus an increase in heating costs. It is, therefore, worthwhile to replace the single glass or to insulate better.
Installing double or triple glazing is then the obvious choice. This is a significant investment, but it is the most sustainable solution. Fortunately, in addition to having double glazing installed, there are also cheaper alternatives. Some of these you can do yourself.
Why insulate windows?
Poorly insulated windows are a major source of energy loss and create drafts and coldness at the windows. A poorly closed window or single glass can quickly lose 15% of your energy. This means extra energy consumption and therefore more heating costs. In addition, a drafty house can be very unpleasant
Improving the window insulation creates more living comfort. Good insulation ensures that the house heats up faster. The temperature in the house is also better maintained and cold from outside does not penetrate inside.
In the winter months, good window insulation will keep the heat in your home. During the warmer summer months, well-insulated windows keep the heat out. The result is a constant, pleasant temperature.
Good insulation has a sound-absorbing effect, so noises from outside do not penetrate the house as quickly.
Increase home value
By applying good window insulation you can increase your energy label. Research shows that a higher energy label can significantly increase the resale value of your home.
Finally, heating costs go down because of the extra insulation of the window. Perhaps the most important reason to tackle poorly insulated or single glass. This will significantly lower your energy bill. At the bottom of this article you can see how much you can possibly save.
This reduction in energy consumption also contributes to lowering CO 2 emissions. By insulating your windows, you therefore contribute to a living environment that is better for the climate.
Measures to insulate your windows
There are various ways to insulate your home and thus make it more sustainable. In many cases, these methods can even be performed yourself, if you're a bit handy. Do you want to be sure that it is done in a correct, sustainable way? Always hire a professional.
1. Apply insulating film
You can stick insulating foil on the glass (window foil), or you can stretch it on the frame (frame foil).
Insulating window film can be applied to the inside of single or double glazing. Usually when glass replacement is not possible or not desired. With insulating window film you significantly increase the insulation value of the window. So you can per square meter glass up to 15 m 3 of gas savings per year (compared to single glass).
Professional window film is almost as pricey as HR++ glazing because you have to have it applied by a specialist. Including installation, this costs about 150 euros per m 2 .
Although the insulation value of insulating window film is a lot less than HR++ or triple glass, it can be a good alternative when glass replacement is not possible. For example, it is cheaper than monument glass (see below).
Be careful with applying so-called anti-view/privacy foil, which are applied to the outside of the glass. These layers often have a sun protection effect, so that you can actually use more energy.
2. Hanging closing (roller) curtains
By making smart use of connecting (roller) curtains, you can make optimal use of the energy and heat in your home. Close the curtains in the evening to keep the heat in the house. Make sure that the curtains fit well around the window. In the morning when the sun appears, open the curtains again. Your house will then be heated by the sun free of charge.
However, leave the (roller) curtains hanging just above the heating. When the curtains fall over the heating, the warm air comes between the curtains and the window. In this way a lot of heat is lost.
If you want to go a step further, you can opt for double (roller) curtains (also called pleated curtains or pleated curtains), possibly with an aluminum coating. The “air chambers” of this type of curtains have an insulating effect. The cold from outside therefore has no chance to penetrate. If you have already invested in curtains and do not want to purchase new curtains, you can also have this extra insulation layer of an aluminum coating installed.
3. Install secondary windows
It may be that installing double glazing is not an option for your home. For example, if you live in a monumental building or have stained glass windows. There are then two alternatives.
Your window or frame is not adjusted here, but an extra pane is placed in front of or behind the existing pane. This creates an airtight space between the existing window and the secondary window. This provides extra insulation, as is also the case with double glazing.
A secondary window has the same advantages as HR++ glass. It has an insulating and soundproofing effect, but the original window is preserved. It costs an average of €125 per m 2 and is therefore in many cases cheaper than replacing a window with HR++ glass.
A secondary window cannot be mounted directly against the original glass and is therefore not always airtight. This can cause condensation to form between the windows. When you have the secondary windows installed by an expert, they will ensure sufficient ventilation to prevent condensation.
If the appearance of the monument must be preserved, you can opt for specially developed monument glass. This glass has been processed in such a way that it has a monumental appearance. It looks old and is quite thin, so that it can possibly be placed in the existing frames. This type of glass is available both single and double.
With a specially applied coating, the window has an insulating effect, as with double glazing. It is not fitted against the original window, but is a replacement window in itself. The appearance of the monument building is thus preserved. Good insulating monument glass does come at a price. The costs for double monument glass are between €200 and 275.- per m 2 .
4. Sealing Cracks
In an average corner house you can reduce gas consumption by about 70 m 3 by closing seams and cracks. A large part of these seams and cracks are located around the windows. It is therefore worth checking your frames and windows.
Drafts can be unpleasant and can also cause mold in the long run. You can reduce the draft in your home in several ways. Sealing seams and cracks in the house will make the house feel more pleasant and you can save considerably on heating costs.
Draft strips or draft tape
You can close gaps around the window frames with draft strips or draft tape. These are available in different widths and materials (usually provided with EPDM or EPT rubber). They are often available from €5 per meter.
You can cut weather strips to size yourself and place them on the hinge side of a window or door. They are not suitable for every situation, because they are quite stiff (hard profile).
Draft bands are also easy to install yourself, because they are flexible and self-adhesive. You can save about 4 m 3 of gas per meter of draft strip . Different variants are available, such as tires with PUR, PVC, EPDM, EPT or PE. So be well informed about which sealing material is most suitable for which surface in your home.
Sometimes the cracks and seams around window windows are too large to be sealed with weather strips or weather strips. In those cases, replacement/renewal of the windows is often the most sustainable and effective solution. Be alert for new cracks when installing new frames and have the installation carried out by an expert.
5. Replace single glass with HR++ or HR+++ (triple) glass
Single glass, standard double glass and HR glass are outdated techniques and are only used for repair work. Due to the increased insulating effect, new homes now have HR++ or triple glazing as standard. Before discussing the possibilities of HR++ glass, let's take a closer look at the definition of HR++ and triple glass.
What is HR++ and triple glass?
HR comes from the abbreviation high-efficiency glass and stands for glass with a high insulating effect. The ‘+' stands for the insulation value. The higher the number of pluses, the better the glass insulates.
With HR++ and higher, a (noble) gas filling is added between the glass layers, with better insulating properties than air. In addition, HR++/+++ glass has a metal coating that provides extra insulation. HR glass with triple glazing is also called triple glazing in addition to HR+++.
Replacing your single glass with HR++ or triple glass is the insulating measure that yields the most results. If you replace single glass throughout your house with HR++ glass, you can quickly save 450 euros on your gas bill.
In addition to the fact that HR++ insulates glass very well, it also has a damping effect. Outside noises are less audible and noise from the house does not penetrate outside.
In colder weather, condensation can form on the windows due to the temperature difference between inside and outside. This mainly happens with single glazing and old double glazing. Due to the extra high insulation value of HR++ and triple glass, you are much less bothered by this.
Finally, HR glass is stronger than single and older double glazing. This provides extra burglary protection and less likely to break a window when children are playing.
Upgrading old double glazing
Is your home already fully equipped with older double glazing? Even then it pays to replace this double glazing with HR++ or triple glazing. HR++ glass insulates about 2.5 times as well as the older standard double glazing. In the longer term, this investment will certainly pay for itself.
Costs and savings HR++/Triple glass
Replacing your single glass is an expensive affair. This way you will quickly lose € 130 per m 2 including installation on HR++ glass. The better the insulation value of the glass, the higher the cost.
The cost of window insulation also depends on:
- The size of the windows to be replaced (small, custom-made windows are often more expensive due to the cutting costs)
- The material used for window frames
- The type and number of layers of glass
- The type of gas filling (argon or krypton)