What will it cost you to heat your home this winter?

What do you think your carbon footprint will be? How concerned are you about your impact on the environment? Will you be environmentally responsible or will you be burning fossil fuels and racking up the kilowatts on your meter?

Recent NZ studies have shown that we spend up to 40 per cent of our energy costs on heating and cooling the home. A lot of this money is literally going out the window!

Ideally, the goal of window coverings is to trap air between the glass window and the back of the window covering to prevent it escaping into the room. You would be surprised at how inefficient average glass is at protecting us from ambient temperatures outside.

If you don’t believe me you can test this yourself. Place a thermometer inside your window against the glass. Check the temperature after an hour - you might be surprised! Glass is a conductor, which is why when you hold a glass of cold liquid in your hands it feels cold, and a glass of hot liquid feels hot. Many Aussie homes are built using lots of glass (as it is cheaper than most building materials), so temperature transfer is a huge problem. E glass goes a long way to alleviate these issues, but it is expensive and still not as effective as using the right window coverings.

There is, however, an easy way to deal with the of heat loss.

It is important to note that not all window coverings perform the same, even those advertised as “blockout.” Aluminium venetians and vertical blinds are the poorest performers as they have gaps either on the sides or vertically/horizontally that impair the coverage of the window. This cannot be avoided (no matter what the sales person tells you) as allowances need to be made for brackets and projection.

Studies show that heat/cold transfer is still at 100 per cent with these products. Roller blinds perform marginally better at 92 per cent. The minimum gap for rollers is about 17 millimetres on each side and you would be surprised as to how much can seep through these tiny gaps (just like a draft under a door!) Plantation shutters are better again, although gaps are still present around the edges.

By far the best window covering to reduce your energy consumption is fully lined curtains and pelmets. Pelmets prevent air from escaping upwards into the room, and a total block out lining prevents air escaping elsewhere. These types of window coverings also perform well in hotter months where the exterior heat needs to be kept out.

By having your curtains professionally manufactured and installed, you can ensure a good seal around the sides, top and bottom, giving outdoor conditions very little chance to seep inside. These types of window coverings only allow 67 per cent transfer, a 37 per cent improvement on other more basic window treatments!

Those who live in colder climates are well informed of this and if you drive through the streets of areas where temperatures can be extreme, you will see many more curtains on the windows than blinds or shutters.

Perhaps the high cost of curtains and pelmets may at first appear prohibitive, but let me make a comparison. When you factor in the initial cost of air conditioning an average home, together with the ongoing costs to run air conditioning, it becomes apparent that a more passive and environmentally friendly alternative needs to be considered. After all, just about every new home built in Australia in the past five years has air conditioning as a standard inclusion, yet other energy aspects such as water usage and electricity are controlled by Basix rules.

Most new homes are water efficient; appliances are energy efficient; some areas have recycled water or grey water for irrigation; yet what is the public thinking on efficient window treatments? Think about it: if you had to give your home an energy rating based on efficiency in all things - water, energy, heating/cooling, and so on - how high a score would you give? Are your windows covered properly? If they’re not, then your score would be considerably lower than someone who has invested wisely in their window coverings.

Our forefathers used draperies to keep the ambient internal temperature of their homes pleasant in the absence of technology, and it was for all intents and purposes, highly effective. If we are truly serious about reducing costs and our carbon footprint, then blockout curtains are the way forward.