Another year, another opportunity for self-improvement! So why not consider similar goal setting for your property? In the face of the winter cold snap, perhaps it’s a good time to reflect on just how warm and cosy your home actually is…or could be.
Resolution N° 1: seriously address the energy efficiency of your doors and windows
Did you know that double paned windows were actually invented and used in some corners of the world as early as the 1930s? But it wasn’t until the 70s and 80s when society took serious note of the importance of improving energy efficiencies and double glazing became an industry standard.
Recent advances in manufacturing technology mean that double and triple glazing installed today is hugely more energy efficient than even 20 years ago. In fact, if your double glazed windows were installed in 2000, you might be surprised to know that they likely allow 2-3 times more energy to escape than their “modern” counterparts.
Beat the heat (loss)
Ok so we know that windows and doors are often a significant culprit for regular heat loss from any home. Just how much is a rather cumbersome calculation that depends not only on the windows themselves but also on the size of the building and just how well the walls and roof are insulated.
But before getting caught up in the maths, if your windows and doors are of a certain age, not to mention if you are remotely concerned with your home’s environmental impact, you might consider calling in an expert to determine if they should be replaced and at what cost. If you are a lucky Canton of Geneva homeowner, you have been obliged since 2016 to upgrade or replace any windows not conforming to current norms. According to the federal energy office (OFEN), you could economise an average of 15% on your heating costs, the equivalent of 500 litres of heating oil annually for the average family home.
Grants and tax credits for upgrades
What is more exciting—there are federal and cantonal subvention programmes, sometimes also supported at the communal level, that could mean a rebate to you when you invest in new windows and doors. There is also the added financial incentive in Switzerland and France of a qualified tax deduction for expenses related to home renovation and maintenance—a real plus. So money spent on this type of home improvement will save you income tax. The French Fisc also reduces the sales tax (VAT) from 20% to 5.5% on works that have an energy impact.
However, another useful thing to know is that double or even triple glazing is most effective when the structure’s envelope (read: foundation, walls and roof) is sufficiently insulated as well.
Most Swiss subvention programmes reflect this reality: among the conditions required for you to be eligible to receive a subsidy, most relate to the global nature of the renovation you undertake. For example, incentives on upgrading windows and doors are only made available to qualified homeowners who also make other refurbishments, such as adding roof or façade insulation.
Your window installer should be able to give you information on the size and technical details of available rebates not only for windows and doors but also other energy upgrades. You can also have a look here if you live in Vaud, in Geneva or in France.
Double versus triple glazing
Another thing to keep in mind—not all windows are created equal. Because there is currently only a small difference in price these days in Switzerland between double and triple glazing, most installers automatically default to the latter, and not necessarily with good reason. It is true that a thicker glass surface will retain heat more efficiently but it will also reduce the amount of passive heat captured from the sun’s rays, especially during cold winter months when such energy is free and welcome in most homes.
Triple glazing also requires sturdier frames to retain the additional weight, which can mean a reduced glass surface area thereby reducing the passage of natural light. The window frame, and the material it is made from (i.e., wood, aluminium, PVC), generally has a lower insulating property than the glazing so larger frames have an effect on the calculated energy coefficient. And finally, thicker frames often come with visible hinges which are seen as less appealing aesthetically particularly if you fancy a minimalist modern design.
The importance of aeration
A final consideration when replacing windows and doors, particularly when moving to triple-glazing, concerns the general circulation of air throughout the house. Airtight windows means less used air escapes and less fresh air enters naturally and circulates in your home. This is not ideal for those with allergies or other air-borne sensitivities, and it can also lead to humidity build up particularly if the house is not regularly aired. For this reason, triple-glazing is often installed with a passive ventilation duct embedded in the window or door frame.
So depending upon your specific geographical and climactic situation, not to mention annual sun exposure, double glazing may be sufficient to ensure you are minimizing your energy consumption while maximizing comfort levels in all seasons.
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