Damp, drafty, tired: When to improve your windows

DualGlaze double glazing can be easily retrofitted into existing frames.

2. Changing temperatures

It's no secret that homes in New Zealand have a reputation for getting cold in winter, especially the older ones. Indeed, according to building sustainability experts Level, 21-31 per cent of heat loss in an uninsulated timber-framed building is through the windows.

If you're noticing that your house is feeling colder than usual it could well be your windows that are to blame. A good test is to stand near your windows on a cool day - if the area surrounding them is noticeably less warm than other parts of the house, you may have found your culprit. A further detection technique is to hold a lit candle near each corner on your windows. A flickering flame points to a draft. Between 21-31 per cent of heat loss in an uninsulated timber-framed building is through the windows.

Another indicator that your home may be suffering from poor window insulation is if you're seeing an otherwise unexplained rise in your energy bills. If your windows are letting out warm air in winter (or indeed letting cool air out in summer) your air conditioning will need to work overtime to maintain the desired temperature. While replacing glass may seem an inconvenient task, it's worthwhile when you know you could be saving money in the future.

So, what can you do?

A great solution for excessive window heat loss is to opt for double glazed windows, such as from Dualglaze. By trapping a layer of air between two panes of glass, double glazed windows can significantly improve the energy efficiency of your home, making it both more comfortable and with less expensive heating costs.

This is especially true if you use low-emissivity (Low-E) glass, which allows light and heat in as normal, but reflects some thermal energy back into the room. According to the Energy Efficiency & Conservation Authority, Low-E double glazing cuts window heat loss 20 to 30 per cent more than standard double glazing. Luckily, double glazing can often be easily retrofitted, meaning new double glazed units can be slotted into existing joinery.