Replacing all the windows in an Ottawa home typically takes 1-3 days of on-site installation for a 12-20 window home, but the total contract-to-completion timeline is usually 8-16 weeks because of measurement, custom manufacturing, and contractor scheduling. This 2026 guide covers realistic Ottawa window replacement timelines including brand-specific lead times, Canada Greener Homes rebate paperwork timing, and the seasonal considerations that affect installation quality.
Most full-home window replacements in Ottawa take **8-16 weeks contract-to-completion**: 6-12 weeks for measurement, custom manufacturing, and scheduling plus 1-3 days of on-site installation. A typical 15-window Ottawa home installs in **2 days**. Larger 20-30 window homes take 3-5 days. Single window replacements can usually be installed in 2-3 hours each.
Fastest realistic timeline — using a contractor with current availability, choosing in-stock standard sizes (rare for full-home replacements), and accepting a non-premium brand — is **3-5 weeks contract-to-completion**. The vast majority of Ottawa window replacements use custom-sized windows that require 6-10 week manufacturing lead times.
Window replacement projects in Ottawa get delayed most by: (1) **Manufacturing lead times** — Andersen and Pella custom orders typically run 8-12 weeks from measurement, (2) **Measurement-to-order delays** — many contractors wait 1-2 weeks after signed contract to schedule the technical measurement appointment, (3) **Brick-mould and trim discoveries** — older Ottawa homes (pre-1980) often need brick-mould replacement or trim repairs that add 1-2 days to the install per window.
**Week 1:** Quote signed, deposit paid. **Week 2-3:** Technical measurement appointment (every opening measured to 1/8 inch precision). **Week 4-12:** Manufacturing (Andersen 8-10 weeks, Pella 6-8 weeks, mid-range brands 4-6 weeks). **Week 13-14:** Delivery and install scheduling. **Install days (1-3 days for typical home):** Old windows removed, new windows installed and shimmed, exterior caulking, interior trim work, debris removal.
Most like-for-like window replacements in Ottawa do not require a permit. Permits ARE required when: changing window opening sizes (enlarging or shrinking the rough opening), adding new windows where none existed, changing egress configurations in bedrooms (must comply with OBC 9.9.10), or modifying load-bearing wall openings. Plan review when permits are required: 10-15 business days. Final inspection rarely required for window replacements but may be needed if the work was permitted.
**Best months for installation:** April-June and September-October. Summer installs work but are uncomfortable for the family because of heat/air loss during the install. Winter installs are technically possible down to -10°C but installers work slower and caulking adhesion is reduced below 5°C. Avoid scheduling installs for December-February if you can — most Ottawa window contractors will recommend pushing to spring for quality reasons.
Yes, but at a cost. Most Ottawa contractors will quote 15-30% premiums for accelerated schedules that require evening/weekend crews and expedited permit handling. The bigger constraint is usually material lead time (especially for custom orders) and Ottawa permit reviewer availability, neither of which can be rushed by paying more.
Change orders mid-project. Even a small scope change can add 1-3 weeks because materials need to be re-ordered, inspections re-scheduled, and trades re-coordinated. Lock down your final scope and material selections before the project starts — every decision you defer to "we'll figure it out" adds days to the schedule.
Work backwards from your target finish date and add 30-40% buffer. Ottawa contractor schedules book 8-16 weeks out for spring/summer starts. If you want to be finished by Christmas, your contract should be signed by July at the latest.
In Ottawa, permits must be issued and posted before any work that requires inspection can start. For interior work, this often only delays the start by 2-4 weeks. For additions and exterior work, the wait can be 8-16 weeks because of zoning review and Conservation Authority comments.
For most occupied-home renovations, yes — final inspection typically happens after you've moved back in. For new additions, secondary suites, and basement secondary dwellings, occupancy requires the final inspection to pass first.