Archive for the ‘Windows and Doors’ category

Skylights’ Function in The Active House

March 12th, 2014
Velux skylight operable with blinds

Velux skylight with blinds and operable glazing

Some green builders and energy auditors would argue that skylights have no place in a “green” home. After all, skylights puncture the building envelope allowing heat to escape in the winter and enter in the summer. Improper installation of skylights can add problems such as condensation build-up inside and ice damming outside.

However, in a house built to Active House standards, energy is an incorporated into the design but is not the driving component.  An Active House balances energy efficiency and human comfort by allowing natural daylight, fresh air and summer cross breezes into a building, while excluding excessive heat, cold, and glare from direct sunlight. This goal naturally means the home will have an abundance of windows and skylights — a direct contradiction of building philosophies such as Passive House which requires extremely tight building envelopes.

There have been many studies done on the positive effects of natural daylight on people’s health, and for those of us who live in northern climates and have suffered, even a little, from seasonal affective disorder, they will recognize the value of natural light, especially in the winter months. So while building envelopes are compromised with the addition of skylights, other green building goals are more than satisfied.

VELUX, a company established in Europe over 70 years ago, is well-known for its high-quality skylights. It has been involved with the Active House philosophy since its inception. I spoke with Nels Moxness and Russell Ibbotson of VELUX about the roles of skylights and their pros and cons in any building.

There are four major issues/concerns people have with skylights: air tightness, insulation value, solar heat gain and glare.

Air tightness: It’s no secret that many people who have lived in a house with skylights have experienced leaking at some point. While it can be due to faulty installation, often it is because the original skylights were installed using tar as the sealer around the flashing. Nels told me that after a few years of exposure to weather elements such as heat, cold, sunlight, water, snow, etc., the tar shrinks and cracks allowing water to infiltrate and find its way into the house. VELUX has always used a an engineered flashing which does not require sealants to maintain water tightness.  Their current product has the addition of  a rubber based membrane, which provides a shield from ice and water that often outlasts the roof’s shingles and prevents leaking. Further, to ensure proper installation of its skylights, VELUX certified installers  are required to attend a comprehensive installation training as well as have a job site inspected upon completion.

Insulation: With respect to insulation values, VELUX skylights are double-paned, flat glass, LoE³  that are filled with argon gas. This provides for a better insulation value than uninsulated skylights. The U-value for the installed skylights in the Active House in Thorold, Ontario is rated at 0.4 in Energy Star zones A, B and C (most of Canada’s population lives within these climate zones, Zone D, the coldest, covers the Arctic).  Note that there are 14 skylights in the Thorold house and the house achieved 1.6 air changes per hour. To give you an idea of how that compares to building code, the upgraded Ontario Building Code, 2012, and the newest Novoclimat (Quebec) building code require a minimum of 2.5 air changes per hour for a detached home.

Solar Heat Gain and Glare: Often, even in winter, if the sun is beating down on a house, without the protection trees or other buildings, the area under the skylight within the house will become so hot or bright that you avoid it completely. This effect is particularly brutal in the summer and will have the added consequence of forcing your air conditioner to work overtime. In fact, solar heat gain and direct glare from poorly placed skylights can negate any natural daylight advantage there is to installing them in the first place. Nels mentioned that with respect to solar heat gain, in the latest VELUX skylights, there is three times less solar heat gain than there was even ten years ago.  Further, VELUX is developing an exterior awning system to prevent solar heat gain and help block glare even more. As it is, you can add an interior blind system, operated by remote control, this is particularly relevant in a bedroom if you don’t like waking up with the summer sun (in Montreal in June, dawn starts around 4:30am and sunrise is at 5am). In fact the addition of a light-blocking blind to a skylight can increase energy performance by as much as 45%.

As the technology of skylights continuously improves, skylights’ importance  in a home’s design and functioning becomes increasingly valuable and homes built to Active House standards take full advantage of the newest skylights’ multi-functional qualities.

The multi-functional skylight:  The Thorold house is designed with 14 skylights which are used to bring daylight into areas that might not receive it otherwise such as bathrooms and stairwells. With increased daylight, demand for electric lighting is significantly decreased versus a standard house.

The ability of VELUX skylights to open to let in fresh air and let interior hot air escape allows architects who promote natural over mechanical ventilation to make use of stairwells as heat stacks.  When the cooler night air advances, ground floor windows can be opened along with skylights. As the hot air escapes through the skylights, the cooler night air gets sucked into the house to replace it. Cooling down a house is much more rapid, easing pressure on air conditioning and the electrical load.  Further, VELUX has just incorporated a solar panel into its skylight to operate it, so there is no need to add to the electrical load.

Rain Sensor: Because the skylights are operable, they include a rain sensor so if you aren’t home and it rains, they will close automatically.

Effectively placed and properly installed skylights can be a positive addition to any building, providing natural daylight in hard to reach spaces, lowering electrical lighting loads and improving occupants’ overall well being.

To find a Velux dealer near you visit the Velux website.


SageGlass — Energy Efficiency Using Tinted Dynamic Glass

January 19th, 2012

For architects and builders concerned with a building’s energy efficiency, windows have always been a double-edged sword. On the one hand they offer views, natural light, and heat in the winter when the sun is shining. On the other hand, they’re holes in the building’s envelope allowing for heat transfer in the wrong direction and glare when the sun’s rays are low. In south-facing rooms in particular it’s always a challenge to offer a comfortable environment, and natural daylight during midday without drawing blinds or having the air conditioner work overtime. One technology that offers a solution but is still relatively new is electrothermal glass, also known as tintable or dynamic glass.

SageGlass was founded in 1989 but took 14 years of research and development before launching its electrothermal glass product. This glass is able to change its tinting to block or allow the sun to enter a building. If you’ve ever been in a building which is enveloped in glass, you might have had the uncomfortable experience of having the sun beat down on you. It’s worse than being outside because there’s no breeze to combat the heat, and the only way to avoid glare is to use sunglasses, which, if you’re inside, isn’t really a great solution.

Advantages:  Tintable glass cuts glare and heat during the hottest times of the day and year but also allows the sun to enter during colder times of the year. The advantages are increased energy efficiency for both the heating and cooling system, as well as permitting  natural daylight without the glare which helps plug load. It also means that blinds aren’t needed, except in areas where privacy is a concern.  A study of increased energy consumption saw that windows with SageGlass increased a building’s energy efficiency  21% over ASHRAE baseline building requirements. Heating and cooling systems will work better, particularly on extremely hot days.

Applications: This glass has been installed in several commercial and institutional building projects but also has applications in high-end residential setting. The advantage of tintable glass is that it permits views while preventing excess heat and glare.  The glass can be specified by any window company, currently for residential applications, Marvin Windows and Doors uses this glass.

Regarding overall energy efficiency of the glass, not only does it allow or prevent radiant heat (heat from the sun) passing through, but it is also treated with a low-emissivity coating to increase the glass’s thermal rating. SageGlass works very closely with all window manufacturers using its glass to make sure it is installed into the window frames correctly. In residential applications, it has been combined with both double and triple glazed windows.

Solar Heat Gain Coefficient: One of the measurements of energy efficient windows is the solar heat gain coefficient. It is the amount of heat that passes through a window from the sun’s rays and is measured on a scaled from 0-1. The average low-e double glazed window has a solar heat gain coefficient of .47, meaning that it lets in 47% of the sun’s heat that is hitting the window. A window coated with SageGlass has a variable solar heat gain coefficient that ranges between 0.09 and 0.49. When the window is fully tinted, only 9% of the sun’s heat gets through. The solar heat gain coefficient of regular glass is static.

Technology: The technology SageGlass developed involves five layers of nano-ceramic coatings. When a small current of electricity is applied to the glass lithium ions and electrons transfer from one layer to another causing the glass to darken. It can be controlled manually or built into a building automation system. In case you’re wondering about whether the electricity applied offsets the gains in energy efficiency, the voltage applied is very small and the benefits of the tinted glass far outweigh the costs.

When used in residential applications, regarding the electrical requirements, the same person installing your internet cables is the one specified for installing this glass.

Cost: While the company couldn’t give a cost for this glass because it depends on so many factors, it is definitely a product intended for high-end residential applications. However, I can see plenty of residential applications for this glass — especially in Toronto where there is a significant number of high-end condos being constructed. Most of these condos are made out of glass, and the upper floors are all about the views. This glass would be a perfect application.

For more information on SageGlass and electrothermal glass, visit




How to Shop for Windows

July 19th, 2011

Windows are usually the “path of least resistance” when it comes to heat loss/gain. Because you’re cutting a big hole in your building, it’s not hard to see where your heat loss is likely to come from. So compromising on window quality could cost you more in heating and cooling bills than you will be saving on your window purchase.

round and vintage wooden window on a brick wall building

Our windows are of medium quality and, while only four years old, I noticed the other day that they are already beginning to warp. Good windows don’t warp. Good windows open and close easily despite the temperature outside and inside. Good windows frames don’t deteriorate after only four years. Conclusion: Our windows suck. (Note: these windows were installed when we bought the house. When I asked the builder which company the windows were from, I learned it was a reputable local manufacturer, but the builder chose sub-quality windows….to save money. Big surprise.)

So, IF you have to replace your windows — and really think about that, because a lot of older wood windows with storm windows don’t necessarily need to be replaced, just restored —  as with anything, buy the best you can afford, with maximum energy efficiency. Energy resistance here is measured as “U” value which is the inverse of “R” value and therefore you strive for a lower number (clear as mud, right?).

There are at least five things to consider when choosing energy efficient windows.

triple-paned window profile

  1. Single, double or triple paned (glazing). Unless you are building in a climate that is 20C 365 days of the year day and night, you should consider buying double-paned windows. They protect against the weather significantly better than single-paned glass. Whether or not to go the step further and invest in triple paned depends on many factors. They are usually significantly more expensive and the additional weight needs to be taken into account when adding to an existing building or new build.  [note – if you live in a designated historical house, you may be restricted by what you can do. Check local by-laws to see what is permitted.]
  2. The spacers between the glass panes and the frame. The seal can wear over time due to exposure to direct sun and extreme temperature swings. Ask what the spacers are made of. Metal spacers can hasten the seal breakage as they can expand and contract quickly in direct sunlight.
  3. The insulation used in the window frame itself, and between glazings (glass panes). What type of gas (if any) is being used between the double or triple-paned glass? Usually argon or krypton are the gases of choice and offer the best protection against air-flow.
  4. The installation process and insulation added around the window frame. Above all else, if the windows aren’t installed properly with sufficient insulation wrapped around the frame, they won’t be as effective as they are intended to be. Make sure the installers know what they are doing and fill and seal any gaps that are left after the windows have been installed and before the rest of the framing is put in place.
  5. High-quality frame: Glass expands and contracts at one rate and wood, aluminum and vinyl all expand at different rates. It means that the seal between the glass and window, if not well-made, will separate and the seal can break. A fiberglass frame provides one of the best framing materials because the material expands and contracts at the same rate. Aluminum frame is one of the worst frames because aluminum is a conductor of heat/cold.
  6. Adding a low emissivity coating, and argon gas to the windows for more effective resistance to heat loss/gain. Note, that in cooler climates the low e coating should be applied on the interior side, and in warm climates on the exterior glazing.)Glass expands and contracts at one rate and wood, aluminum and vinyl all expand at different rates. It means that the seal between the glass and window, if not well-made, will separate and the seal can break. A fiberglass frame provides one of the best framing materials because the material expands and contracts at the same rate.

Inline Fiberglass Windows — Warm on the Inside Even When it’s -11 Celsius Outside

May 3rd, 2011

Haliburton Cottage

It’s no exaggeration to say “you had me at -11” when I think of Inline Fiberglass windows. If you’ve read my article on the First Certified Passive House Residence in Canada then you might remember the part about putting my hand up to the windows and the glass feeling warm even though it was -11 outside! (Sorry about the finger prints.) In my house I’d know where the windows were located even if I were blindfolded because of the sharp temperature drop as I approached them.

Fiberglass is one of the best materials on the market for windows, in fact, it might even be considered the best material for windows. It has many qualities about it which make it an excellent choice for window materials, and Inline Fiberglass windows are known as some of the highest quality fiberglass windows made in North America. And, they’re made right here in Toronto.

Here are some of the attributes of Inline Fiberglass windows that make them so appealing for a “green build” or renovation:


Shawanaga Bay Cottage

1. Stability. Fiberglass, made from 60% glass, expands and contracts at the same rate as the window panes. This means that the seal between the frame and panes stays solid.

2. Insulation. The frames are well-insulated and there is no thermal bridging so heat can’t find its way out of the windows through the frames.

3. Manufacturing control. The fiberglass frame is manufactured in-house through a method called pultrusion, so the company can maintain complete control over the entire process.

4. Durability. These windows last and last and last. They are unaffected by arctic cold or dessert sun. They are also non-corrosive which makes them attractive for oceanside locations.

5. Low embodied energy: fiberglass is considered one of the lowest embodied energy materials compared to other common window frame materials.

Mnjikaning First Nation Early Childhood Education Centre

6. Recyclable: At end of life, the fiberglass can be ground up into a fine powder to be used in common building components, as well as fill in the fiberglass resin before it is put through the pultruder.

7. Low maintenance. In general, fiberglass windows need very little attention. Their frames don’t fade and don’t need repainting, repairing, or refinishing.

8. Customization. Windows are available in five standard colour shades, can be made as “inserts” or “full frames” in any size, with many different insulation options available. Further, there options for double glazing (two window panes), or triple glazing (three window panes) available and different insulating gas combinations including argon and krypton (krypton is an even better insulating gas than argon). Note: window “inserts” might be preferred if you live in an historical home and want to preserve the wood frame.

9. Flexibility: windows are available in casement, tilt ‘n turn, double and single hung with tilt ‘n turn options.

10. Warranty: windows come with a Limited 20-year warranty on the frame.

Front and back of Toronto residence with Inline Fiberglass windows

11. Pricing: It’s impossible to price out windows because of all the different combinations and customization features. It’s best to contact the company directly.

For more information on Inline Fiberglass windows, visit their website.

Phone: 1-866-566-5656


(Photos courtesy of Inline Fiberglass.)

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Accoya Wood: Durable, Stable, Modified Without Toxins

April 26th, 2011


Bridge made from Accoya

I was at a presentation, hosted by Upper Canada Forest Products, to hear about the features of Accoya wood. This is a wood product which looks really interesting specifically for any outdoor use. Matt Roberts is the Technical Sales Manager for the Americas for Accoya, and he presented on this product.

The product  was introduced in 2007 in The Netherlands. Accoya is a pressure-treated wood, however, it is treated with non-toxic ingredients, and it will last 50 years or more when exposed to outdoor weather elements. The entire wood piece is treated with an acetylation process so that every fiber of the wood is exposed to the acetylation process, not just the outside layer. What that means is that cut ends exposed to harsh weather will stand up just as well as the rest of the wood. The treatment process used actually changes the molecular structure of the wood and makes it more durable. Unlike traditional pressure-treated wood, however, it is completely non-toxic. The chemical used is acetic anhydride, a derivative of acetic acid, which is the base of vinegar. In fact, Matt told us that the wood gives off a faint vinegar smell when it’s being worked with.

Durability: It has an above ground outdoor guarantee of 50 years and a below ground and fresh water guarantee of 25 years. This is a pretty amazing guarantee for a wood product that will be exposed to all the weather elements.


swellometer measures absorption of water

Stability: Because the acetylation process keeps wood from bonding with water, it is hardly affected by the changes in temperature or humidity. In fact, at the beginning of the presentation, Matt put a piece of Accoya and an untreated piece of wood in a small tank of water and measured their ability to absorb moisture over the length of the presentation (about an hour). At the end there was a significant amount of swelling observed in the untreated wood, and barely any in the Accoya wood. Note the measurement was performed by a — I kid you not — “swellometer.”

Insect resistance:, Termites and other insects will stay away from it if there are alternative food choices (ie., other available wood sources), for it to eat.

Finish: The wood comes “rough hewn” and needs to be finished and sanded. Stain and paint last longer on Accoya than on regular untreated wood because of its stability. There is no contracting or expanding, which means paint and stain don’t wear as quickly.

Type of wood used: The wood used is a soft wood called Radiata Pine. It acetylates well which is why Accoya has started out with this wood. Although once it has been treated with this procedure the wood becomes 50% harder than in its original condition.

Decking made from Accoya

FSC certified: The wood used for this treatment is sourced out of well-managed, FSC-certified forests in Chile and New Zealand and treated at the main facility in The Netherlands. Eventually, the company will be licensing out the technology to wood treatment facilities worldwide to make logging, milling and manufacturing close to local markets.

Applications: Accoya is an excellent wood choice for a variety of residential applications: In addition to windows and doors, Accoya can be used for exterior siding, decking, shutters, fences, sound barriers, outdoor furniture…. (Two window and door manufacturers already use Accoya, Bonneville and Dynamic.)

One thing to note: because of the acidic nature of the wood, it was suggested that a few hardware materials such as zinc or galvanized steel be avoided because of their likelihood of being oxidized. Better choices are stainless steel, anodized aluminum, brass, any epoxy or ceramic coated hardware.

Wood frame made from Accoya. Note mitred corners will always remain stable

Cost: The cost of Accoya is the equivalent of a tropical hardwood, however, longevity of the product should be taken into account when considering pricing. This wood is ideal for specialty products with long-term exposure to the elements: windows, doors, shutters, wood trim, etc.

Accoya is available through Upper Canada Forest Products and is sent to manufacturers for further applications.

(Note: photos courtesy of  Accsys Technologies, PLC)

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