selecting energy efficient windows

If shopping, compare prices but do not forget the rating of the windows, expressed in their energy performance label. Make sure that the rating concerns the window as whole and is valid for your climate.

Do not base the selection of your windows on their prices. Low prices are often equivalent to lower quality and higher energy costs.

High-quality windows will pay themselves with energy savings. The payback period will be shorter, and you will get more comfort and increase the value of your home.

Selecting your Windows

When selecting windows, consider...

- the type of glass, and the number of panes;
- the quality and the insulation of their frames and sashes;
- the spacers;
- the type/design of the windows (casement, sliding…);
- their size;

Window Performance Label provides the easiest way and the basic information for selecting an efficient window You can assess the three first elements by the coefficients of the rating label of the window, and you may just consider that label, but it's important to understand some related details to make an informed decision.

See, for details on window rating coefficients:
Best windows rating
Windows for cold, hot and mix climates
.

The window glass and the spacers

The glazing is the core of the efficiency of any window. Old clear class is something of the past. Today’s energy efficient windows involve double (or triple) pane windows, low-E coatings, inert gas fills and, eventually, some sort of tinted glass...

Window spacers (between the panes, at their perimeter, to seal the gas space between the frames) are also an important element to consider. They are a thermally weak area in many windows.

See: Types of window glass

Window frames and sashes

Window frames should provide strength without compromising the efficiency of the window.

When selecting windows, pay attention to their frame materials and the insulation of their cavities. Fiberglass and some composite structures with foam insulation in their cavities are excellent options, but there are new modern alternatives, namely based on vinyl. Wood is definitely a material of the past, in what concerns windows...

See:
New efficient windows
Window Frames and Sashes

Types of windows

The type of glass panes or the type and materials used on the sashes and frames are key features for the energy efficiency of windows. But there are other features like the type or design of a window that are not negligible, and should also be considered. See: Window designs and types

Buying & Size of the windows

If you are building a new home, avoid large areas of east and west-facing glass. You will be rewarded by lower air conditioning bills and glare.

Also do not forget a basic rule: it’s better some few large windows than many small ones. Larger windows will increase the proportion of glass relative to frame and sashes, making them thermally stronger.

Climate zone, home design and landscape

The shape of the building, its sun-facing sides or the surrounding landscape have an obvious impact in the size and type of glaze of the windows (which may vary with the side of the house).

But most of all do not forget that your climate determines the type of glazing and the best features for the windows. You must select and buy your windows according to your climate. Mild, cold, hot and mixed climates have different requirements…

See, on these issues: Windows for cold, hot and mix climates

The window warranty

Another point that you should consider when selecting windows it's their warranty. Is it a "limited" or "full" window warranty? Full warranties mean that the window manufacturer must repair or replace the windows at no charge.

A Full Lifetime Window Warranty is the best warranty you may have. Full warranties meet federal minimum standards for written warranties, contrary to limited warranties. Under a limited warranty the manufacturer may charge costs associated to the repair or replacement a defective window.