THE GREEN WINDOW DEBATE:

     This week’s column returns to the historic, circa 1894 church that is being renovated and turned into an Eco80 home. You can always catch up on the progress at www.alltechgreenchurch.ca. While the interior planning has changed somewhat from our early thinking, as most renovations will, we are now moving full speed ahead, with most of the demolition having been completed.

     Some ordering has to be done in advance.  Given that they are custom sized, with delivery times of 6-8 weeks being the norm, windows definitely fall into this category. If we order now, they should arrive in early July; just about the right time.

    Buying windows can be a daunting task, even for the most progressive contractor and I am no different. While windows should meet the Energy Star standards, this is really a minimum benchmark with today’s realities. One of the more confusing areas in use is way we describe insulation values.  We have both U-Value or Factor, as well as R-Value. Natural Resources Canada (NRCanada) describes U-Value as “the rate of heat transfer from warm to cold areas in watts per square foot…..the lower the value, the slower the rate of heat transfer.” Clear as mud!  From a consumer perspective this is not exactly intuitive as the U Value number goes down as the effectiveness of the window’s insulation improves. The other issue is the very small degree of U rating that can make a difference. Going from a 0.15 to a 0.05 window may seem small, but, in effect, it’s a huge averaged difference. Because we see the term commonly used, we have become better attuned to hearing about R Values. In fact, R-Value in windows is the opposite of the U-Factor. NRCan clearly states that R-value is not part of the energy performance standards. To quote, “R-value indicates the resistance to heat transfer in square feet per hour….the higher the number, the greater resistance to heat transfer.” Some years ago windows had R-values fewer than four. With the improvements on the market, today we could expect that number to be as high as eight.

    For a number of reasons, we have selected windows by Vinyl Window Design (VWD) from Fort Glass, in Kingston.  First off, they meet the EnergyStar standards and come with a lifetime warranty. As well, of the close to 2000 window manufacturers in Canada, they are one of only 30 certified under the “Window Wise” program. This program, in my opinion, should be mandated for every retail window manufacturer. This organization certifies not only window manufacturers, but installers as well. To meet the certification, windows must meet or exceed the CSA A440 standard for air infiltration, water penetration and wind load strength. They have a list of other criteria, including quality of frames, spacers and forced entry ratings. More info at: www.windowwise.com

    I spoke to Darren Clark, Technical Rep at Fort Glass, about some of the features of their windows and about windows in general. My first question concerned their recommendation in regard to lowE coating. Darren explained that there are actually two kinds; soft coat and hard coat. Soft coat is a film of sorts, which has a slightly better U rating than the hard-coat low-E. If a home is reasonably updated and air conditioned, this is probably the better choice. He prefers the hard-coat low-E coating for our climate, however. This hard-coat is actually done when the glass is in the molten stage and it has a better solar value. In effect, it allows more heat in, captures more of it and does not allow it to leave the home. When you factor in our heating degree days and the fact that most replacement windows are going into older homes that are not as energy efficient, I can see his point.

   There are two gas injections done in most windows and here Darren was clear that Krypton will give you approximately 25% more insulation value. However, it can run upwards of 10 times the cost vs. the more popular gas, known as Aragon. With the capital cost value vs. the recovery for the average working family, it’s a hard sell for him. Spacers are also quite a discussion point. Aluminium is well known as a poor insert, allowing heat transfer, while foam and fibreglass (which is more costly) are also used. Darren stated that the stainless spacer they use is a good compromise and gives value for the overall window energy efficiency. We discussed glass thickness. Most glass today is 3mm.  4mm is available, but mostly used for sound values. Darren felt that window retailers should concentrate on finding a good, energy efficient and cost reasonable replacement for their clients, as, while windows are necessary for home comfort and natural lighting, you can go overboard. I am in agreement with this. and the addition of good solar blinds can make a major difference.

     NRCanada and the Office of Energy Efficiency have an excellent web site www.oee.nrcan.gc.ca/equipment/energystar.  This web site explains the climate zone minimum standards for each geographic area in Canada. In south and central Ontario, we fall under Zone B. There are other ratings, for example the majority of operable windows are rated for air tightness.  A window with an “A1” rating is far less airtight than one rated A3

    Buying windows should not only be based upon how pretty they are, color of the frames, inserts, etc.  It would be better to concentrate on getting the most overall value before looking at the cosmetics.  On that note, we will be adding “Krumpers Solar Blinds” to our windows and will say more on these spectacular Canadian made blinds in a future column.