Who this guide is for
- Homeowners replacing windows in part or all of a home
- People concerned about draughts, leaks or condensation
- Anyone comparing window installers
- Owners wanting warranties handled properly
Judge measuring accuracy
Windows must be measured precisely to fit the opening, especially in older or out-of-square frames. Ask how they measure and survey before ordering, since errors here are costly.
Careful measuring is the foundation of a good install.
- Ask how openings are measured
- Discuss out-of-square openings
- Confirm a survey before ordering
- Avoid guesswork on sizes
Probe flashing and sealing
A window keeps weather out only if it is flashed and sealed correctly around the frame. Ask how they weatherproof the install and handle the junction with the wall.
Leaks and draughts usually trace back to poor sealing.
- Ask how the frame is sealed
- Discuss flashing and the wall junction
- Confirm weatherproofing of the install
- Address draught control
Check warranty handling
Windows often come with warranties that depend on correct installation and registration. Ask how the installer handles warranties and registration so cover is not lost.
Confirm what the warranty covers and who registers it.
- Ask how warranties are handled
- Confirm who registers the warranty
- Understand what cover applies
- Keep the paperwork
Confirm glass and ventilation needs
Some locations need safety glass or specific ventilation, which is a specification matter. Confirm the installer specifies appropriately and keep these decisions with qualified people.
Do not overlook safety glass or trickle ventilation.
Brief and compare on the same scope
Give each installer the same information about the windows and openings so quotes compare. Ask what could change once the old windows come out.
Confirm insurance and relevant experience.
- Share the same window details with each
- Compare on like-for-like scope
- Ask what could change once removed
- Confirm insurance and relevant experience
Hiring checklist
- 1Decide window style and material
- 2Ask how openings are measured and surveyed
- 3Discuss out-of-square openings
- 4Ask how the frame is sealed and flashed
- 5Confirm weatherproofing of the install
- 6Ask how warranties are handled and registered
- 7Confirm any safety-glass or ventilation needs
- 8Give each installer the same brief
- 9Ask what could change once windows are removed
- 10Confirm insurance and relevant experience
Common mistakes to avoid
- Ordering windows without a careful survey
- Overlooking flashing and sealing around the frame
- Losing warranty cover through poor registration
- Ignoring safety-glass or ventilation requirements
- Comparing quotes that cover different scopes
- Skipping insurance and experience checks
When to involve a professional
- Keep glass specification and any structural opening changes with qualified professionals
- Confirm safety glass and ventilation are specified where needed
- Ask to see comparable window installations
- Ask to see relevant insurance for the work
- Remember window and glazing requirements vary by location and project
Frequently asked questions
Questions readers ask about this topic
Why is measuring so important?
Windows must fit the opening precisely, especially in older or out-of-square frames, and errors are costly. Ask how the installer measures and surveys before ordering, since careful measuring is the foundation of a good install.
What about flashing and sealing?
A window keeps weather out only if it is flashed and sealed correctly around the frame, and leaks and draughts usually trace back to poor sealing. Ask how they weatherproof the install and handle the junction with the wall.
How are warranties handled?
Windows often come with warranties that depend on correct installation and registration, so cover can be lost if this is missed. Ask how the installer handles warranties and registration, and keep the paperwork.
Do I need safety glass?
Some locations need safety glass or specific ventilation, which is a specification matter for qualified people. Confirm the installer specifies appropriately, and remember requirements vary by location and project.
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