Windows of opportunity

Kya deLongchamps

There are a number of financial, aesthetic and practical considerations when planning the refurbishment of existing windows.

Glass

Main consideration: Thermal performance.

The average heat loss from a single glazed window is 5 watts per metre squared. A high performance Argon gas-filled, 16mm cavity double glazed window brings this down to 1.5 or even 1.1 watts. What does all that waffle mean?

Well, if you have vast, floor to ceiling windows, the difference to your energy bills to heat the house could be radically affected as the windows will not be merrily conducting Ten Euro notes to the outside world. Single glazed panels are cold on the inside. In a double glazed unit, with a radiator set below it, the inner face is obviously warmer, attracting less condensation problems. Night vents, which feature on most new units give you a facility for locking the window open a crack whilst keeping them securely locked. There may also be a vent built into the frame for ‘trickle ventilation’ requirements. However, double-glazing in itself is now standard fare, and will win back only a portion of the money it cost generally (estimated at about one third of its price) if you sell you home.

Low emmsivity glass such as Pilkington ‘K’ is the way of the future and is regarded as the industry standard since the Part L of the Building Regulations came into play in July 2002. This revolutionary glass carries a microscopic metal coating that reflect long wave radiation from heat sources from within such as the warmth of a fire and other heat sources, while allowing short wave radiation from sunlight to be transmitted from outside. This glass is also warmer to the touch making it less prone condensation that other glass.

Teamed with argon filled units, low E glass provides excellent insulation values and as a high-spec ingredient, low E units will increase the comfort and potential sale value of your home so don’t settle for less.

Pilkington Activ self-cleaning glass (www.pilkington.com) is proving a huge hit after one short year on trial on the Irish market. Senator Windows, the major supplier of PVC window units in Ireland was given an exclusive contract for Pilkington Activ self-cleaning glass for use in their windows and conservatories in March of 2001. This brilliant system uses an integral coating that works with the natural forces of the Irish weather to literally clean itself. It costs about 15% more than conventional glass in a comparable double glazed unit, but what price could you put on not having to repeatedly swab filthy and often perilously out of reach windows? Quality timber or aluminum frames set with low E glass with a self-cleaning coating are arguably the highest specification of replacement windows available on the Irish market. This is not just a home improvement, it’s a lifestyle improvement!

Frames

Main consideration: Maintenance and longevity.

The correlation between double-glazing and PVC is almost a tradition in Ireland accounting for 2/3 of the window market.

Why is the sheer practicality of plastic so seductive? There is no mistaking white, plastic framed windows for anything else. Gothic, Tudor, or blankly contemporary, it is still a shallow, smooth, plastic frame that can jar with the solid character of brick, wood, or stone. If you have concerns about the environmental concerns surrounding the use of this material, take a look at the battery of research available on the World Wide Web regarding toxic emissions. Wood grain PVC is considerably easier on the eye but after a decade the pigment will migrate and turn a greyish colour.

Heritage Officer for an Taisce Ian Lumley, points out ‘most PVC windows scrape through the 10-year home guarantee scheme’. Question your supplier about longevity as well as considering the short-term rewards of economy and low-maintenance.

Metal-framed windows never went out of style in the States and Canada and there is evidence to suggest that they are seeing an upswing here with the wonders of wood windows clad in weather-tough aluminum by Loewen and Marvin.

These windows are a tailored high-end commercial product that demand bespoke prices of up to 20-30,000Euro for even an average sized home. Metal frames must be well detailed to avoid any ‘cold bridging’ that can lead to condensation inside the window.

Timber windows are surging in popularity, both in tropical hardwoods and pressure treated softwoods like pine and larch. With modern commercial joinery systems, these windows offer the aesthetic beauty of wood married to the advances in design of it’s PVC equivalent such as multi-point locks. Yes, wood demands more concerted care than plastic, but it is much more eco-friendly and new micro porous stains together with better quality timber have radically cut down maintenance time. Whipping original wood windows out of a period home and replacing them with metal or PVC units can drastically affect its appeal to purist buyers. There are a number of companies championing the traditional box sash window in timber. For a price they can construct, refurbish and recreate box sashes. A full overhaul will include the repair of weak joints, re-glazing, a full inspection and re-oiling of pulleys and the installation of new wax cords in a fully draught-proofed window that should give decades of trouble free, high performance service. Slide action sashes are now available in PVC, but bear in mind that they are cannot be dismantled as easily as their timber equivalents, and will be replaced long before a well-maintained wood version.