Windows

Windows are expensive and rarely make economic sense to upgrade as the savings associated with them are minimal compared to the capital cost. However, they can make a huge difference in terms of comfort and this has value.

Windows are the ‘eyes of the building’ and really help to create the character of a home, so it is important to get the right design and material choices for each elevation of the building. Older buildings just look better with timber windows for example and also a style that reflects their heritage helps to preserve their integrity as well as the wider streetscape. Wood, metal or plastic are all options commonly available, but they come in different styles that your home might ‘demand’.

Take time to think about your choices and their wider implications of your locality.

Windows are also used as an essential element of our ventilation systems at home, so think about your ventilation strategy when changing windows. It is best to specify trickle vents in your windows as these provide background ventilation for the whole house*. In order to make these more effective it is worth looking at relative humidity controls on the vents, especially those that will work alongside a relative humidity constant extraction system. This starts to create something called a Demand Controlled Ventilation system.

* Trickle vents should be specified for ‘habitable rooms’ (bedrooms, living rooms etc) and not for ‘wet rooms’ (bathrooms, kitchens etc as these should have constant MEV extractors installed).

In purely practical and energy terms old draughty single glazed windows can suck the heat from the room and you. To address this the choices are:

• Secondary glazing or replacement glazing with double glazed units
• Replacement with new double glazed windows
• Replacement with triple glazed windows

Secondary glazing

Keeping and restoring old sash / single glazed windows might be necessary due to planning considerations (listed building, conservation area status etc). If this is case there is great advice available from: https://historicengland.org.uk/images-books/publications/traditional-windows-care-repair-upgrading/heag039-traditional-windows-revfeb17/

Replacement with new double glazed windows

Double glazed units are generally sufficient for the Welsh climate and they are available in a range of forms including outward opening, inward opening (easier for cleaning) and there are no end of options available but in energy terms you want to look at a minimum of A rated windows. These will have good insulating glazing and frames. A rated is equivalent to around 1.6U value. But ideally specify a 1.2 or 1.4 U value window.

If you are in a noisy area then you can specify a 6:4 arrangement (6mm pane combined with a 4mm pane – most are 4:4) as this is classified as an acoustic window and will be similar in noise reduction performance to a triple glazed unit.

Replacement with triple glazed windows

Triple glazed units are the next step up in terms of energy efficiency and noise reduction, however much of this is lost if they are still being used as part of a ventilation system. Triple glazed high performance windows are best when combined with more complex heat recovery ventilation systems. Their extra efficiency, weight and cost rarely makes much practical sense unless one is looking to create a ‘Passiv Haus’ level of insulation and energy management.