Keep winter outside with the help of double-glazed windows.
Keep winter outside with the help of double-glazed windows.
The gap between two sheets of glass in double-glazed windows helps keep the cold out and the heat in (right); if your property has heritage features such as sash windows then you may be able to add double glazing to the existing wooden joinery (left).
Keep winter outside with thehelp of double-glazed windows.
If your rooms have that ice-box feeling, your noisy neighbours are driving you crazy, or your windows are crying with condensation, then double glazing might be worth considering.
South Islanders have been double glazing their windows for decades. In the past North Islanders tended to suffer in silence when it was cold. We've now woken up to the fact that heating, insulation, ventilation, and now double glazing can make our houses more comfortable to live in, says Ronnie Pocock, marketing manager at Fletcher Aluminium.
It's worth noting that double glazing is not the same thing as secondary glazing. Double-glazed windows have two sheets of glass with a gap between them, which is filled with gas or a vacuum. Secondary glazing involves installing a second layer of glazing on the inside of the existing window. Both have their proponents and detractors.
The gap between two sheets of glass in double-glazed windows helps keep the cold out and the heat in.
There are so many options available that it's easy to glaze over listening to them all. You can buy cheap films, magnetically attach acrylic sheets, add aluminium-framed secondary glazing, or retrofit double glazing into existing frames.
The window unit itself can be replaced, or re-engineered to take double glazing. And then there are added extras, such as argon gas between the panes of glass and low-e (low emissivity) glass.
Low-e is a film that reflects heat. "It's really good for rooms that get stiflingly hot," says Pocock. As well as retaining heat in winter, low-e glass in particular keeps heat out during the summer.
Standard double glazing is the entry-level product, says Pocock. Argon-filled glass is nice to have and argon plus low-e is the "bee's knees".
"With your double glazing you can add a UV tint to the glass which will help protect your furnishing from sun damage."
If your property has heritage features such as sash windows then you may be able to add double glazing to the existing wooden joinery.
Double or secondary glazing does reduce energy costs. However, the payback time can be as much as 28-30 years in Auckland for a permanent secondary glazing system, Consumer magazine found. Not everyone who installs double glazing in their homes is doing it for financial reasons.
Consumer recommends that homeowners try temporary secondary glazing before buying a more expensive system.
"It may be all that you need," says Sue Chetwin, chief executive at Consumer.
The cost of retrofitting double glazing to a typical three-bedroom home starts from about $7000 to $10,000, says Pocock.
There are many different types of systems and some posters on the Ecobob.co.nz website talk of spending $30,000 on totally replacing existing windows in a house.
It's not necessary to do the entire house in one go, says Pocock. Some people choose to do the children's bedrooms, or the south-facing rooms, and finish the job later.
Prices vary a lot. Double-story homes require scaffolding, and houses with 30-year-old windows or older may need more work done.
Homeowners with heritage features such as sash windows and/or leadlight windows can in many circumstances add double glazing to the existing wooden joinery. Villa windows aren't always symmetrical, so it can be an expensive job.
Double glazing is only part of a heat loss solution. It's usual to insulate the home first and to add modern heating/ventilation.
Finally, says Pocock, double glazing works best in houses with active or passive ventilation. Active is a heat pump or ventilation system. Passive is vents in the windows. Otherwise you're moving the condensation elsewhere in the house.
