Doors & Windows
WHEN TO REPLACE WINDOWS ?
NIGEL HEADFORD CAB CHIEF EXECUTIVE
Few homes today are still single glazed , most have double glazing installed , so why consider changing them ? The Council for Aluminium ( CAB ) has drafted a handy homeowner guide on how to determine when windows need to be replaced .
Windows are important for letting in natural light , keeping out the cold and enhancing the aesthetics of a home . The lifespan of windows can vary depending on different factors , double glazing in windows typically last around ten years , but , with proper installation and maintenance , they can last even longer . The chosen material of the window frames affects their lifespan . Timber frames can last up to fifty years with regular maintenance , which includes repainting on average every five years . PVC frames are typically replaced after approximately fifteen years , and aluminium frames can last sixty years or more with minimal maintenance .
“ WHAT SHOULD I LOOK FOR IN EXISTING WINDOWS ?”
Apart from the visual aspect which prompts replacement , there are several other signs to look for when determining if windows need to be replaced . Condensation between glazing panes indicates broken seals , which compromises insulation and soundproofing . It is crucial that glazed units are ventilated around their perimeter , something that is provided by aluminium and PVC systems , but more difficult to determine in timber systems .
Difficulties in opening or closing windows may indicate damaged hinges . Warped frames , noticeable drafts , frame rot , missing weather seals and locking issues are also signs that windows may need to be replaced . Mould on reveals suggest that cold bridging is occurring and this needs to be investigated prior to window replacement . Faded furniture and carpets near windows suggest that the
windows do not have more modern UV protection . Excessive noise transmitting through to the inside can also be a sign that windows need to be replaced , as modern windows with double or triple glass panes and seals provide better sound insulation .
“ SO WHAT HAS CHANGED ?”
Thermal efficiency of window systems has improved significantly over the last few decades , from the older timber or steelframed single glazed windows , to todays triple glazed systems . Thermal efficiency has taken centre stage and although you may already have double glazing installed , new , more efficient window systems offer better aesthetics , ease of operation , lower maintenance costs and better insulation for the home whilst increasing comfort . Question is , when is the optimal time to replace windows and doors ?
Old double glazing is probably not gas filled , particularly windows with narrow air spaces , but , even if they were , gas does escape over time reducing the glazed unit performance . New glazed windows should offer an optimal airspace within the glazing of 16mm and be gas filled with either argon or krypton gas . Argon ’ s thermal conductivity is roughly 67 % that of air and inexpensive , most companies use this gas fill as standard . Krypton gas is best used in glazed units with a narrow air space , since it functions best when there is a thin gap between the panes about 10mm or less . For this reason it is often used in triple-pane glazed units , where there is an additional layer of glass for additional thermal performance .
“ WHEN SHOULD I REPLACE MY WINDOWS ?”
The thermal performance of current replacement windows and doors are close to what is going to be required for our low-carbon future , where the energy we do use in heating comes from renewable sources . Products do exist which offer even higher levels of insulation and when coupled with an increase in building fabric efficiency takes us to a ‘ Passivhaus ’ standard which requires a space heating energy demand of not more than 15 kWh per square metre of net living space per year . New buildings and refurbishment properties are increasingly turning to this standard for homes and commercial spaces . Scotland is to introduce its own Passivhaus standard next year for all new homes .
www . c-a-b . org . uk
34 JUNE 2024 CLEARVIEW-UK . COM