Wooden sash windows with glazing bars

Wooden sash windows are the most environmentally friendly option for a number of reasons. Whether you’re choosing between wooden sash windows or uPVC, or even the less common option of aluminium sash windows, there are various factors to consider when it comes to environmental impact.

1. Raw materials

When the timber is carefully sourced and treated, wooden sash windows will be far more long lasting, economical and environmentally friendly than other types of sash windows.

Most wooden sash windows are made from fast growing pine trees, from sustainable, managed forests. This means that for every tree that is cut down, a new tree is planted.

Then, in the case of a timber such as Accoya, the pine is treated to increase its stability and durability. This means that even in poor weather conditions, the windows won’t swell or warp, to maximise their life expectancy and reduce unnecessary waste. Accoya timber, for example, is guaranteed for 50 years above ground – reducing the need for Accoya sash windows to be re-painted or replaced.

uPVC sash windows, by contrast, are not environmentally friendly as uPVC is derived from oil which is an unsustainable, reducing source. It is also pumped with chloride gas during the production process, which is derived from the burning of fossil fuels.

2. Replacement, repair and recycling

House exterior with wooden sash windows

Unlike wooden sash windows, uPVC can’t be repainted, so in the event of any damage or decay, would need to be completely replaced. uPVC is porous so it is likely to fill with pollution from the air and discolour. It is also likely to degrade in the sun, and become brittle and yellow, so uPVC windows will need to be replaced more frequently than wooden sash windows. Any replaced uPVC windows are hard to recycle and go into landfill where they take over 100 years to decompose.

If wooden sash windows need to be repaired, components can be replaced or repainted without needing to replace the entire windows. Sections of damaged timber can also be removed and replaced. And if the wooden window frames are still in good condition, new sashes can be fitted to the existing frames.

Timber can also be safely reused, recycled and incinerated in the event that wooden windows do need to be replaced.

Aluminium sash windows, being made with a natural material, are also more easily recyclable, and because of the durability of the metal, less likely to need to be replaced. Although aluminium windows will corrode over time and will need to be fully replaced, their life expectancy is expected to be 10 years more than uPVC windows.

3. Thermal efficiency

Improving the insulation of a property will help to reduce energy consumption in a home, thus helping to protect the environment as well as keeping utility bills down. Windows are a notorious weak point in a property as they are much more heat conductive than the surrounding walls.

As well as improving insulation with draught proofing and double-glazing, the material of the window frame is also a major factor in terms of the thermal insulation of a sash window.

Wood is naturally very good at insulating heat, although different timbers have different levels of thermal efficiency. Accoya timber is more thermally efficient than other commonly used hardwood and softwood species.

uPVC is also a thermally efficient material, but aluminium, as a metal, is very bad at insulating heat. To get around the poor insulating abilities of aluminium, some window manufacturers offer ‘aluminium clad’ windows – timber windows with aluminium clipped on top.

4. Preserving the neighbourhood

One final factor to consider in terms of environmental impact is the overall look of a property and the neighbourhood. Period properties would have originally been made with timber windows, and so to maintain the original look of a period property and keep it in the same style as neighbouring properties, timber is the only viable choice.

Obviously if you are selecting windows for a modern apartment block, this may not be such an important factor. But maintaining the original period look of properties in a neighbourhood can have a big impact in terms of improving respect for an area and the overall community.

Are you looking to replace your sash windows?

At Timbawood we specialise in the finest single and double glazed timber sash windows for period and modern properties. Get in touch to speak to one our specialists about the options available.