How to Specify Eco Windows

Climate change affects everyone, and we all want to improve the current situation. So when it comes to buying products for your home, every decision can make a difference – and choosing the windows and doors for your project is no exception. After all, a typical home loses anything from 10% to 40% of its heat through the fenestration.

So what do you need to know in order to select products that will support the performance goals you want to achieve, deliver on comfort levels and ensure you’re making an environmentally-friendly choice?

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In this article, we’re going to focus on the makeup of your windows – in particular, the typical energy efficiencies and carbon footprints associated with the main frame and glazing materials.

But you’ll also want to consider the overall architectural design: will your windows play a role in free heat gain, for instance, and are you aiming for eco standards such as Passivhaus?

Crucially, whatever product you select, it must also be properly installed – otherwise it simply won’t achieve the performance level you’re expecting. At Idealcombi, we offer a comprehensive online manual and app so you can be confident your installer gets it right.

Frame materials

There’s a range of options here, and it’s important to understand that each has its own benefits. The key is weighing up aspects such as the window’s baseline thermal efficiency, lifespan and maintenance requirements, whether the materials are recyclable and deciding what balance works best for you.

Don’t forget things like acoustic performance, too; a good result here could be the difference between something you live with for decades, and something that needs replacing  in just a few year’s time (thereby increasing your carbon footprint).

Idealcombi’s Idealcore is a unique material that’s imperishable and 100% moisture resistant

With timber windows, look for FSC certified products. This means the wood comes from well-managed forests where ecosystems are protected. These products can be carbon-negative over their life-cycle. In comparison, plastic and aluminium take more energy to produce but both require very little upkeep and can be recycled.

Timber aluminium composite frames (alu-clad) combine the best traits of highly insulating timber windows with the benefits of a low-maintenance, durable and thermally broken metal external finish – giving you lifelong efficiency. Idealcombi was a pioneer of the alu-clad window back in 1988, and we continue to push the performance and sustainability credentials of this style.

Our products benefit from the additional Idealcore component, which has several functions and dramatically reduces heat loss through thermal bridging compared to a timber core. Its imperishable profile also works to protect the internal timber finish and extends the window’s lifespan.

Glazing specification

The thermal and acoustic performance of a window or door has to be taken into account when establishing eco credentials, and the glass spec has a huge impact on this aspect. There are many different types of glazing that can help you get the result you’re looking for. For instance, modern double glazing can achieve excellent performance, using gas fills and the likes of low emissivity (low-E) coatings to minimise heat loss. Depending on your project goals, this may be sufficient for you – or you might want to upgrade to super-insulating triple glazing.

Low-iron glass is another product you might encounter. This increases solar gain, letting more of the sun’s energy and warmth into your home. This can provide a free boost of heat that suits north-facing properties or projects where a passive solar design approach has been adopted.

By contrast, solar control glass reflects or absorbs the sun’s radiation and may be beneficial on large expanses of south-facing glazing. All of these choices should be talked through with your architect and window supplier to identify the best solution for your home.

Main image: Idealcombi supplied the windows and doors for Stirling Prize winning project Goldsmith Street by architectural practice Mikhail Riches. The slim sightlines, long lifespan and great thermal performance have created an energy efficient result.