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About Your House
CE 28f

Window and Door Renovations

Windows and exterior doors are subject to the wear and tear that comes from constant use and exposure to the weather. Over time, weatherstripping, hardware and the door and frame materials can deteriorate or fail. Homeowners can either repair or replace window or door units. Repairs can be inexpensive, but may not give good long-term results. Replacement is generally costly, but will provide cost savings in energy use, make your house more comfortable and add to the resale value.

Common Situations

There are a number of factors to consider before making the decision about whether your windows or doors need to be replaced or whether they can simply be repaired.

Some important areas that you will want to consider include:

  • Style and design — your existing windows and doors may not fit the style of your house or give you the features that you want. There may not be enough glass area to provide adequate natural lighting to the living space.
  • Components and hardware — the components of windows and doors wear out over time. Failed seals on thermal pane window units, poorly operating windows or doors, damaged screens or hardware and air leaks are common problems. Older door and window hardware may not offer much protection against forced entry.
  • Structural problems — there may be structural problems that are affecting the operation of doors and windows. Installation of larger units or units in new locations will probably also require structural changes.
  • Moisture — windows and doors often deteriorate due to moisture problems, which will not necessarily go away if you install new units. In fact, moisture may even get worse, due to reduced air leakage.
  • Heating and ventilation — the glass area of windows and doors accounts for a high degree of heat loss at night or heat gain when the sun is shining. Energy efficient glazing can reduce heat loss. Heating system modifications or some type of shading may be needed to improve comfort near large window areas.

Healthy Housing

Renovating is an ideal time to make your house healthier for you, the community and the environment. When assessing your renovation project, be sure to consider the five essentials of Healthy Housing.

House as a System

A house is much more than just four walls and a roof — it’s an interactive system made up of many components including the basic structure, heating, ventilation and air conditioning (HVAC) equipment, the external environment and the occupants. Each component influences the performance of the entire system. A renovation provides an opportunity to improve how your house performs.

Tighter and more energy efficient windows and doors will reduce the heating load on your house, reduce heating costs and improve occupant comfort. Energy efficient glazing can also reduce condensation problems that damage finishes and lead to mold growth. Increased house airtightness can improve energy efficiency, but may also lead to a greater need for mechanical ventilation. A sufficient air supply may also be needed to prevent combustion appliances from backdrafting.

Avoid Surprises

There are many choices available to homeowners who want to upgrade or make changes to the windows or doors in their homes. Taking the time to examine your needs and the options that are available is the right way to start to plan for your renovation or repair job. Here are some of the likely situations that people encounter.

Style and design
Ask yourself...
  • Do the important living areas of your house receive adequate natural lighting?
  • Do you have or want windows or doors that connect you with outdoor living areas, interesting landscape features or views?
  • Do the windows and doors match the original style of your house?
  • Do the windows and doors have the appearance, durability and maintenance requirements that you expect?
Consider your options...
  • Increase the glass area. For good natural lighting, glass area needs to be about 10 per cent of the floor space.
  • Add windows or doors to connect you with the outside environment. Make sure the weatherstripping prevents or minimizes air and water leakage.
  • Choose replacement windows and doors that fit with the original style of the house.
  • Select windows and doors that meet your needs. If you are replacing all of the windows and doors, you may want to totally change the look and feel of the house by choosing units of a completely different design.
  • Consider the use of a professional designer to help explore your options.
...and if you don't
  • Poor natural lighting can detract from your enjoyment of the renovation. If you compromise on your choices you will have to live with the results.
  • Adding another door or window later will be more costly and may not fit well with other renovation work that you have done.
  • Poor selection can result in windows that look bad, perform poorly or require excessive maintenance. A designer can help to avoid problems such as installing too large a glass area on the sunny sides of the house that can lead to overheating unless sun controls (e.g., large overhangs, awnings or trees) are also included.

Components and hardware
Ask yourself...
  • Are your windows and doors in good operating condition and free from wind or water leakage?
  • Are glass surfaces easy to reach for cleaning?
  • Are storm windows and screens easy to install and in good condition?
  • Are the latches, doorknobs or weatherstripping in good condition?
  • Do your doors have security features such as door viewers, deadbolt locks, reinforced striker plates and hinge attachments?
  • Is your window hardware adequate to resist forced entry?
  • Does each bedroom have a window that allows egress in case of fire?
Consider your options...
  • Replace or repair worn out window or door units.
  • Choose new window units that open or tilt in for easy cleaning. Familiarize yourself with available products and options. Pay attention to energy efficiency features.
  • Replace worn or damaged latches, doorknobs or weatherstripping.
  • Install deadbolts on exterior doors. Use door viewers or glazing to give you a clear look at your caller. Install longer screws at hinges or striker plates. Install solid blocking between the jamb and framing at hinge locations and striker plates.
  • Install bedroom windows that have openings that meet the National Building Code requirement for egress.
...and if you don't
  • Window and door units will continue to be a source of problems.
  • You may put yourself and your family at risk.

Structural problems
Ask yourself...
  • Are there existing structural problems that affect your windows and doors?
  • Will installation of new windows or doors require special structural details or changes in electrical and plumbing services?
Consider your options...
  • Carry out an inspection to help you understand the cause of any existing structural problems. Look for cracked or binding windows and doors.
  • Repair or strengthen structural components so that they are adequate to carry the loads over existing or new openings.
  • Consult with an expert to help you with the structural part of the work. Use a licensed tradesperson to disconnect or move any electrical or plumbing services.
...and if you don't
  • Structural deficiencies can lead to difficulties in operating windows and doors.
  • Other structural problems can show up as cracked finishes or glass, bowing or displacement of walls and roof structures and possible structural failure.
  • Structural, electrical or plumbing modifications that are not up to code can be a safety hazard.

Ask yourself...
  • Is there moisture damage to any of the windows and doors?
  • Is there moisture between the two panes of glass?
  • Is there visible mold growth on any surfaces? Are there water stains?
  • Has there been condensation on glazing, jambs or sills?
  • Is there blistering or peeling paint?
  • Is any of the caulking cracked or missing?
  • Are the flashings in good repair?
Consider your options...
  • Determine the source of the moisture. It may be from building leaks or condensation of vapour on cold surfaces.
  • Replace the sealed unit.
  • Modify or move curtains, plants or window screens that are keeping warm air from getting to the window surface.
  • Clean up visible mold growth according to CMHC guidelines.
  • Insulate, air-seal or use energy efficient glazing to provide warmer inside surface temperatures.
  • Provide ventilation and eliminate sources of moisture to control high humidity.
  • Replace or repair all deteriorated finishes or structural components.
  • Maintain caulking and flashings to prevent water access to the building structure.
...and if you don't
  • Unsolved water damage problems will continue and lead to further deterioration of the building or newly renovated areas.
  • A broken seal will allow moisture to build up between the panes, reducing the window efficiency and possibly causing breakage.
  • Mold growth caused by excess moisture can be a serious source of IAQ problems.
  • Superficial cleanup or hiding moisture damage behind new finishes will allow deterioration to continue.

Heating and ventilation
Ask yourself...
  • Do large areas of glass make the room uncomfortable and hard to heat?
  • Does excess condensation form on windows or other surfaces?
  • Do large areas of glass lead to overheating from the sun’s energy?
Consider your options...
  • Make sure that there is adequate heating supplied to the area. Poor insulation levels and high air leakage will make the area hard to heat, drafty and uncomfortable.
  • Use energy efficient glazing. In some cases, you may need to install additional ventilation to reduce indoor humidity levels. If you are installing a whole house ventilation system, consider one that includes heat recovery.
  • Use a licensed installer for heating and ventilation work.
  • Install blinds or exterior shading to control overheating from the sun and damage to interior finishes.
...and if you don't
  • The heating system may not be able to maintain a comfortable temperature in the living space during cold windy weather.
  • Condensation may damage your work.
  • The sun may overheat the living space.


  • Your window and door repair or replacement can provide you with units that are easy to operate, free from condensation and energy efficient.
  • Additional glass area can result in bright, well-lit living spaces.
  • You can improve the security and safety of your home.

Skills to Do the Job

A homeowner with good fix-it skills may be able to do some of the work on the repair or replacement of windows and doors such as:

  • Replacing hardware or weatherstripping.
  • Repairing caulking or flashing.
  • Installing insert type window replacements.

Consider hiring a professional renovator for structural changes, finish work or complete project management. If you are doing the changes yourself, you will still need to hire subcontractors to carry out the electrical, plumbing, heating and ventilation work. Remember to obtain all necessary permits, ensure that workers use safe practices and are covered by workers’ compensation. Protect yourself, your family and your home.

Use the Window and Door Assessment Worksheet to record the present condition, any window or door problems, proposed upgrades and preliminary costing.

Window and Door Assessment Worksheet
  Present Condition / Problems Proposed Upgrades Cost
Window Size      
Sliding or Ease of Opening, Hardware Operation      
Caulking and Flashing      
Evidence of Moisture Damage      
Condensation on Glass Surface (during winter)      
Fogging or Condensation Between Glass Panes on Sealed Units      
Door and Frame      
Door Security Features      
Window and Door Finishes      

Costing Your Project

The cost of the renovation work will depend on the condition of the existing windows and doors, local labour and material costs and the extent of the work to be done. The cost of doors and windows varies widely. A good budget checklist will help you to develop a realistic cost for the project before you start. Some of the items to include are:

Design changes.

Structural considerations.

Components and hardware.

Moisture damage and deteriorated finishes.

Plumbing and electrical problems.

Heating and ventilation.

Permit and inspection costs

Waste disposal.

Other Useful Information From Canada Mortgage and Housing Corporation

Related Resources

Although this information product reflects housing experts’ current knowledge, it is provided for general information purposes only. Any reliance or action taken based on the information, materials and techniques described are the responsibility of the user. Readers are advised to consult appropriate professional resources to determine what is safe and suitable in their particular case. CMHC assumes no responsibility for any consequence arising from use of the information, materials and techniques described.

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