Energy Saving  Windows

Windows

Windows were once little more than holes cut in walls to let light and air into rooms.

Today they bring beauty and light, warmth and cooling breezes into homes while providing a sense of openness and space.

On the down side, windows can also let in the winter chill or the summer heat.

They can make a home drafty, uncomfortable, and energy inefficient.

Fortunately, modern windows make the most of the benefits of windows while minimizing the drawbacks. Single-pane glass has been replaced by multi-panes separated by insulating materials.

Frames are made of new, more energy efficient materials.

Even the glass itself has been coated to reflect heat.

Today's Windows

Would you willingly toss 30 percent of your energy dollars out the window? Not likely.

On the other hand, that's how much of a typical home's heating and cooling is lost through its windows and doors.

To put that in perspective - the amount of energy lost through doors and windows in the U.S. every year is roughly equivalent to all the energy we get from the oil carried by the Alaska pipeline!

Since windows outnumber doors in most buildings, they deserve the most attention.

You can either fix them to make them as efficient as possible, or you can replace them with some of the new technology that has been introduced in the last several decades.

Today's Windows - How They Work

Early windows were little more than holes cut in walls to let light and air into rooms. With the addition of glass in movable frames, a major improvement in building comfort was achieved, allowing closed windows to let in light and block the winter chill.

Over the past 20 years, windows have become increasingly more sophisticated, using new materials with more energy-efficient properties.

Single-pane glass has been replaced by double, triple and even quadruple panes, with insulating materials separating the layers.

Inert gasses have been pumped between the panes, adding to the window's insulating properties. Even the glass itself has been coated to reflect heat.

These innovations mean that windows can significantly contribute to a home's comfort and energy efficiency. By letting in sunlight, they provide warmth in winter, which will save energy and lower monthly heating bills. Proper design and the use of exterior shading can also lower cooling costs in the summer.

Ventilation and Infiltration

Well-placed windows allow for natural ventilation, which can significantly reduce cooling costs in the summer.

But infiltration - unplanned air leakage through a window's joints, cracks, frames and sashes - can account for as much as 15 percent of a home's heating and cooling losses. It can make a home much less comfortable and more costly to operate.

Modern Windows - Think of Them as ThermosŪ Bottles

When there is a difference between inside and outside temperatures, heat transfers through a window.

It's lost to the outside during the heating season and is gained from the outside during the cooling season.

A window's thermal performance - which can be measured at the centre of glass, the edge of glass and the frame - is rated with a U-value, its overall ability to resist heat flow.

Choosing the right windows can significantly increase your energy efficiency and reduce bills.