Consumer's Guide – To buying Energy-Efficient Windows and Doors

Catalogue No.: M-92-156/2001E
ISBN: 0-662-27162-9

Section 11 –
Getting What You Pay For

11.1 The Importance of Correct Installation

With the increasing complexity of window technology, installation is not something you want to play around with. Unless you are an experienced carpenter, window and door installation is not a do-it-yourself project. A crack in a gas-filled window will limit its effectiveness–and you won't have a warranty if anything goes wrong!

Installation is especially important with high-performance windows because poor installation techniques can negate their superior performance. Installation should be made according to the new CSA-A440.4 "Window and Door Installation Standard." In addition, the Siding and Window Dealers Association of Canada (SAWDAC) has recently developed a certification program for window installers, although it is not widely available across Canada yet. Also, many manufacturers train their own installers. Be sure to ask about installation.

First, windows must be installed square, plumb and level with shims and spacers at appropriate points to ensure durability and continuing high performance.

Once the window has been installed in the rough opening in the wall, care must be taken to ensure good thermal resistance and good airflow resistance around the sides of the window frame, that is, in the space between the frame and the rough opening. High thermal resistance will keep heat loss to a minimum. Good airflow resistance will prevent cold air from leaking in or warm air from leaking out around the sides of the window frame. Because the warm air contains water vapour, it is important to prevent it from leaking into the exterior wall and causing condensation to form inside the wall.

The material most commonly chosen for insulating around windows is injected foam. Injected foam has the advantage of providing good thermal resistance and resistance to the passage of air and water vapour, thus allowing installation in one stage using a single product (Fig. 47). However, the foam has to be applied with great care, because the pressure created by overfilling may distort the frame and cause the window to jam or the glass to break. Care must also be taken to ensure that the foam used is compatible with the materials with which it is in contact, such as the window frame and caulking products. When insulating foam is used with a vinyl or aluminum frame, there is a chance that the bond between the foam and the frame will break as a result of contraction and expansion of the frame.

The older blanket insulation method is an effective solution, but requires careful installation using more than one product (Fig. 48). Blanket insulation offers good thermal resistance but poor resistance to the passage of air and water vapour. For this reason, another material, such as injected foam or a backer rod with caulking, must be used on the interior side. When installing the insulating blanket, care must be taken to avoid compressing it so as not to affect its insulating properties.

Warning: Older homes, especially those built prior to 1950, were often painted with lead-based paint. Caution should be exercised, especially when working with windows, doors, trimwork, wood siding or porches.

11.2 The Contract

Because the supplier has to visit your home and take measurements for each door or window, many suppliers also install windows. The contract in this case would be to "supply and install".

If you are replacing windows, this type of arrangement is a good one. The advantage is that one company is responsible for supplying and installing the windows in your home. Because much of their business is through referrals, suppliers usually do a good job to ensure customer satisfaction.

The "contractor supply and install" arrangement will come up if you are undertaking a major renovation. The general contractor will also likely arrange for the purchase of required windows.

Listen to the contractor's opinions on the type of windows and suppliers, but make the final decision yourself. The benefit of working with a contractor is clear when problems arise and work such as structural changes to the wall or repairs to the drywall and trim must be done. A good contractor will ensure that the windows are properly installed and finished, inside and out.

You should have a contract signed by both parties before work begins (Fig. 49). It should stipulate the full cost of the work, including taxes, and provide a detailed description of the windows. The contract should also outline the products to be used and stipulate that they will meet CSA standards after installation. Make sure it covers the date by which the job is to be completed and describes both the manufacturer's and installer's warranties.

Save costs and avoid later delays by inspecting the windows on delivery to ensure they are what you ordered. Check units for correct size and style, for all certification labels, and for conformity to specifications–sealed units, for example, should bear the IGMAC name. Contact the supplier if special or invisible features, such as low-E coatings, gas fill or non-metallic spacer, are not labeled on the unit, or if faulty units need to be replaced.

And report excessive deflection of glass/glazing and any evidence of seal failure such as condensation, frosting, fogging or discolouration between glazings. Handle all units with care!

The supplier is normally responsible for correcting any problems with the product, while the installer is responsible for proper installation. Whatever the case, do not pay the full cost of the job until it has been properly completed.

You are legally entitled, under provincial construction liens legislation, to withhold a percentage of the cost of any construction project for a specified time to satisfy yourself that all sub-trades and suppliers have been paid by the contractor. This is an accepted construction practice you should follow. Details are available from your provincial ministry of consumer and commercial relations.

Note: Canada Mortgage and Housing Corporation offers a free publication entitled: How to Hire a Contractor (publication number: NHA-5429). To obtain a copy, contact CMHC.

11.3 The Work

You may need a building permit if you are changing the size of an existing opening or making a new one. Check with your municipal office before work begins.

The installation of new windows will likely cause some disruption. Prepare for the work by finding out when the job will be started, and by moving furnishings and pictures.

Be prepared to find structural problems when an old window is removed. Rotting or missing wood, undersized, or improperly supported lintels, for example, must be corrected before the new unit is installed. Enlarging openings or cutting new ones involves structural work, and may require the rerouting of wiring and other services.

The surrounding structure must be sound and dry before the window is fitted, insulated, and air-sealed. Outside, the window flashing or drip cap should extend across the top of the window to direct water away from the window (Fig. 50). New mouldings on either side of the window will likely be required.

There are two ways to place windows and doors in relatively thick walls: close to the outside face of the wall, or close to its inside face. Doors tend to be mounted flush with the inside face for aesthetics and ease of operation. Windows, too, should be mounted close to the inside for energy efficiency, since the window surface is sheltered from the wind and in a warmer part of the wall (Fig. 51).

Once the window is installed, check that it opens and closes easily, locks tightly, and is well-sealed. If condensation occurs between panes of sealed units, the seal is faulty and the unit should be replaced under warranty.

11.4 Understanding Warranties

A window is usually covered by a warranty for performance under normal operating conditions. The recommended minimum warranty for a window, both parts and labour, is one year.

Make sure that the installer's workmanship is also covered by a warranty. For example, if the installer accidentally breaks the Insulated Glazing Unit (IGU) during installation, this type of incident should be covered by the installer's warranty. Installation errors may not show up for a few months. Good glazing practice should ensure that the glazing cavity is drained or vented to the outside. The edge of the insulated glazing unit should not be allowed to sit in water. This may cause failure of the glazing unit. The installer must make sure that the drainage system is not blocked in the process of installing the window.

Most IGU manufacturers offer a five-year warranty against failure of the seal. If condensation or frosting appears between the layers of glazing during the warranty period, the manufacturer will supply a new replacement sealed unit. The consumer is normally responsible for the costs of the installation of replacement units. For details on the Insulating Glass Manufacturers Association of Canada (IGMAC) certification program.

Remember, warranties can be used for marketing purposes. Read the fine print carefully to see exactly what is covered and for how long.

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