How far in advance should I order windows?

This very much depends on whether you’re opting for off-the-shelf windows or bespoke products, and can also differ from company to company. “Most timber window suppliers have a general lead time of anything up to 12 weeks,” says Tony Pell of JELD-WEN, who can provide timber windows in just four weeks.

It goes without saying, but bespoke windows inevitably carry longer lead times. Tom Barfield of Mumford & Wood takes up the story: “The normal process is for architectural drawings of the property to be sent to us and we will quote to that specification; designs can be altered at this stage to suit the specific project. The more bespoke, the longer the manufacturing process. The same applies to standard and non-standard ironmongery. From sign off we will provide a delivery date which can be six weeks or more.”

As such, it’s tempting to order windows at a very early stage, but ordering them too far in advance can also be problematic. “If you are planning on ordering your windows far in advance, one thing to bear in mind is to leave time to make amendments to the building design or aperture sizes so you can account for them in your final order,” explains Tony Pell. “Once you have specified or ordered your new windows it won’t be simple to make changes, so it’s important to be certain about your designs and measurements prior to placing your order.” 

Is triple glazing worth the investment?

Triple glazing usually costs an additional 15–20 per cent more than double glazing, although this price is expected to fall as the market builds (in Europe, where triple glazing is much more common, the prices are closer to double). The general view is that triple glazing can’t justify itself in pure ROI when you compare the additional cost against the benefits for lower heat losses through those windows — but that’s far from the whole story.

Triple glazing offers excellent comfort levels, and you will notice a perceivable difference on colder days. It is a worthy investment when soundproofing is a requirement (i.e. if a home is adjacent to a busy road), too.

The issue is really around where to put it, with most experts agreeing that it’s near-essential on north-facing elevations with lots of glazing and to be generally avoided on south-facing elevations. Although, of course, triple glazing can help to minimise overheating too and suppliers such as Internorm offer special coatings that will allow solar gain when required (i.e. in winter).

What is low-E glass and where should it be used?

Low-emissivity or ‘low-E’ glass (as it is more commonly known) is a type of glazing designed specifically to prevent heat escaping through windows. “The invisible coating reflects long wavelength radiation – generated by radiators, heaters, computers, electrical equipment and even body heat – back into the room. It also transmits short wavelength radiation from the sun (passive solar gain) into the room, which can contribute to heating the room during the winter,” explains Phil Brown, technical expert at Pilkington Glass. “Low-E double glazing can reduce the heat loss through the glass by as much as four or five times compared with single glazing.

“For replacement windows and new windows for extensions, low-E double glazing is required to satisfy Building Regulations in the UK (such as Part L1B in England). In areas of the home susceptible to overheating, such as conservatories or large glazed extensions, solar control glass can also be specified to reduce excessive solar gain in the summer,” concludes Phil Brown.

Are timber windows still high maintenance?

For period and modern homes alike, timber is a great choice, and today’s timber window has come on in leaps and bounds, shrugging off its reputation of old.

“The modern timber window has come a long way in its development since the ‘60s, ’70s and ’80s when basic softwood frames, untreated, were used as the material to hold single panes of glass which were fitted after their installation into the raw brickwork openings. The windows of this era were subject to moisture ingress and rot, which in turn opened up the market for first, aluminium and second, cheap plastic double-glazed replacement windows,” say the experts at Mumford & Wood.

“Engineered timber components are now commonplace and provides for a state-of-the-art finished window that will give a life expectancy of 60 years and more — by comparison plastic windows have to be replaced every 35 years or so. Modern paint and stain finishes also give performance in life, with regular maintenance, equal to that of other materials.”

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