Buying Windows with Confidence
by Doug Beingessner
The installation of new windows can be one of the most significant upgrades you will make to your home.
Since windows are capable of gaining and losing energy, special attention must be given to this balance. Windows lose heat and energy in three basic ways:
1 – Radiant energy escapes through the glass area
2 – Conduction of heat occurs through frames and spacers
3 – Heat loss by convection occurs in the air space inside the insulated glass unit
Your new purchase should include a window unit that deals with all three areas. In order to slow down the loss of heat through the glass area, be sure your window has Low Emissivity glass. Low ‘E’ glass is a special type of glass made with an invisible coating that reflects heat. In our climate this coating is positioned to reflect heat back inside your home before it can escape. This results in a warmer inside surface temperature on the glass and therefore a warmer window.
Heat also escapes (by conduction) through window frames and the spacer bar which separates the two panes of glass making up the insulated glass unit. Generally, most frame components today offer improved efficiency with air pockets, thermal breaks and welded corners. The spacer that separates the glass should be the type classified as a ‘warm edge spacer’ as opposed to the older style metal spacer.
Heat loss is also reduced by replacing the air inside the insulated glass unit with argon gas. Argon gas is an inexpensive, non-toxic, non-flammable, inert gas widely used in light bulbs. Since its convection rate is less than air, it is a wise choice in improving energy efficiency.
There are several other upgrades which also affect heat loss. Triple glazing, heat mirror, smart glass and photo chromatic glass just to mention a few. These can be used to deal with specific energy situations.
Buying a quality window is really only half the battle. A proper installation will enhance the efficiency of the window and allow it to do the job it was intended to do. Remember, some windows actually gain more heat than they lose.
There are two window installation standards that can be used. Insist that your window installation is done according to the C.S.A. (Canadian Standards Association) standard, or the Ontario Hydro Energy Efficient Window Standard. In conjunction with Ontario Hydro and S.A.W.D.A.C. (Siding and Window Dealers’ Association of Canada), installers received formal training in the installation of energy efficient windows.
Buying a good window and having it properly installed by a professional is a wise decision!
Selecting the right energy efficient windows for your home can be confusing. We’ll make it easy by explaining energy ratings, heat transfer and the effects of U.V. radiation. Visit our showroom and see the latest in window technology or contact us for a free in-home estimate.