When it comes to window replacement in Toronto, you will have heard both terms – new construction windows and replacement windows. Most homeowners think of them as two terms for the same thing – just put in new windows. They don’t. The difference between the two is structural, and selecting the wrong type in the situation will result in a major increase in costs, issues with the exterior finishing of your home and damage to your energy performance for years to come.
Whether you’re looking to upgrade an existing house in Toronto or build or add to your home, this guide explains what each window type is, when each one would be appropriate, and how to confidently make the right choice.
What Are New Construction Windows?
New construction windows, also known as flanged windows, nailing fin windows, or full-frame new build windows, fit in cases where the framing of the wall is entirely visible. A new construction window is defined by its nailing fin, also known as its nailing flange or mounting flange – a flat strip that is attached to the entire perimeter of the window frame that extends out from the window itself.
It is nailed or stapled directly into the exposed wall studs when framing is complete, before any of the exterior siding, cladding or stucco is attached. After the window is fastened, the flashing, moisture barriers, insulation, exterior siding and interior trim are applied over and around the window, which becomes a part of the wall assembly.
New construction windows are the right choice when:
- You are constructing a brand new home from scratch
- You’re adding to your home or a bump-out in Toronto or the GTA?
- Creating a window opening from a door opening
- You are resizing an existing window opening (both larger and smaller)
- You are about to complete a big job including the full removal of the exterior siding
- Your window frames are rotting, water damaged or structurally weak right down to the studs
The important thing to know: If your home’s siding is not going to be removed during your work, adding a new construction window must have the siding removed first. That’s a considerable amount of labour and time and then having to repair or replace the exterior cladding afterwards.
What Are Replacement Windows?
Replacement windows or sometimes called insert windows or retrofit windows are designed to fit into a window opening without removing the surrounding wall, siding or exterior trim. They can be available in two main types:
Insert Replacement Windows: The old sash and hardware are taken off and the frame remains. The new window unit fits into the old frame and is fastened around the frame. This is the least disruptive and most economical – works best when your frame is structurally stable, square, and not rotten or water damaged.
Full-Frame Replacement Windows (Flangeless): Removing window sash, frame and all to the rough opening area, and replacing the window with a new window, including a new frame. Exteriors remain intact and interior trim remains. Use in situations where the current frame structure is already damaged, or where a better seal for the air is desired, but exterior teardown isn’t justified.
Replacement windows are the right choice when:
- Need to replace windows in your home that are drafty, foggy or outdated
- The window frames are structurally sound
- Little or no damage to exterior siding, interior trim, or drywall
- No size or location is being changed for any window openings
- You want to reduce installation time and project expenses
- Own a home in Toronto and not planning to renovate outside extensively
For Toronto and GTA homes (including North York, Scarborough, Etobicoke, Mississauga and Markham homes), the vast majority of window upgrade projects involve replacement windows. They are quicker, cleaner and more affordable in houses that are in good condition.
The Key Structural Difference at a Glance
The only real difference between the two window types is one thing – the nailing fin.
It’s designed to be installed on new construction windows. Replacement windows don’t.
The nailing fin determines the way your window fits into your wall assembly. The window needs to be placed over the exposed wall framing before the exterior materials are added to the wall. If not, the window will fit into an existing, finished window opening.
| Feature | New Construction Window | Replacement Window |
|---|---|---|
| Nailing Fin | Yes | No |
| Wall Framing Exposure Needed | Yes | No |
| Exterior Siding Removed | Yes (or installed before siding) | No |
| Interior Trim Disruption | Higher | Lower (insert) to moderate (full-frame) |
| Installation Time | Longer | Shorter |
| Overall Project Cost | Higher | Lower |
| Best Use Case | New builds, additions, major renos | Existing home window upgrades |
| Energy Seal Quality | Excellent (when done correctly) | Excellent (full-frame) / Good (insert) |
Cost Difference: New Construction vs Replacement Windows in Toronto
One of the most commonly asked questions on this subject – and one that is answered by most Toronto window companies – is the cost. Let’s get a better look here.
Replacement windows are always the cheaper alternative to older homes. Lower labour cost is due to not having to touch the exterior siding or rebuild the rough opening. Generally, the average Toronto home can expect to pay between $600 and $1,200 per window for a mid-range energy efficient replacement window, which varies with window size, replacement window style (casement, double-hung, sliding, bay, bow), and glass package.
New construction windows in a replacement-project environment are more expensive – not necessarily because the window itself is dramatically more expensive, but because there is a larger labour scope. The cost of removing exterior siding, flashing properly at the new window, installing new siding and finishing interior and exterior trim come into play. This can drive the total installed cost of these windows up a bit higher than the total installed cost of a similar replacement window installation.
The practical takeaway: When replacement windows are installed in existing frames, they provide similar or equivalent energy efficiency as replacement windows installed in new construction windows, but at lower overall cost.
Which One Is Right for Your Toronto Home?
Apply this quick decision-making tool:
Choose New Construction Windows if:
- You are designing a new home or addition
- As part of this project, your exterior siding is being replaced
- Rotten or failing window frames to studs
- Resizing existing windows or creating new openings
Choose Replacement Windows if:
- You have to upgrade windows in a completed, occupied home in Toronto
- Existing window frames are sound & square
- Keep the impact on the outside and inside of your home to a minimum
- Have contained budget and time frame
After you’ve considered your options, the issue will be solved quickly – with a professional in-home consultation, you’ll explain your situation to the installer, and they’ll tell you for sure what kind of windows that apply to your project.
The Bottom Line
For most Toronto homeowners, replacing windows in an older home that are too drafty or don’t work well – replacement windows is the solution. They are generally easier to install, won’t affect your home decor as much as the interior or exterior, and cheaper if the structure of the interior/exterior is already sound.
New construction windows are used in new construction, home renovations and additions where the wall framing is showing. If they’re not used in this way, they’ll result in un-necessary siding removal and higher labour expenses and a much longer project time.
Before you receive window quotes, knowledge of this difference will save you from overselling yourself the wrong type of windows – and give you a much more productive discussion with your window installer from the outset.
Ready to upgrade your windows? Milano Windows & Doors provides complimentary in-home consultations throughout Toronto & GTA. Your existing frames will be evaluated for the specific situation and the most appropriate window type will be suggested, followed by a clear, written quote, no pressure and no surprises.
Frequently Asked Questions: New Construction vs Replacement Windows
Q: Can new construction windows be used as replacement windows in an existing home?
Yes, in certain situations. New hung windows with nailing fins can be installed if your renovation project includes the removal of exterior siding, for re-siding, insulation upgrades or major structural changes. In some instances, the nails on the fins can be extracted or cut away from a newly constructed window so that it fits into an existing opening, but this increases the difficulty. In most typical Toronto home window replacement scenarios, a suitable window replacement window is the faster, more economical and cleaner option.
Q: Do replacement windows reduce the size of my window opening?
Replacement Windows do reduce the amount of glass visible, as the window you are replacing is placed in the old window frame, not replacing the old window. In most homes, the reduction is only about half an inch to an inch per side, and it’s usually not noticeable. A full frame replacement window (replacing the outside frame of the window) doesn’t incur this loss of glass area, and keeps your exterior and interior finish.
Q: Are new construction windows more energy efficient than replacement windows?
Nope, not always and this is one of the most misunderstood points on the planet. Window energy efficiency is mainly dependent on the window package (double versus triple, low-e versus non-low-e, gas fill versus no gas fill), and less on the nailing fin, but more on the quality of the nailing fin seal. A full frame window replacement with a high-quality triple pane, Low E window will always be better than a poorly installed new construction window. However, it is the window product specification and the quality of the window installation, and not the window type category which is most important.
Q: Do I need a permit to replace windows in Toronto?
Generally a building permit is not needed in Toronto under the Ontario Building Code for a simple in-kind replacement (no structural changes; same size; same location). A permit will be required, however, if window openings will be changed in size, windows will be added on, or if changes will involve the building structure or fire separation. You should discuss permit requirements during the consultation with your window installer depending on what type of work you are doing.
Q: How do I know if my existing window frames are good enough for inserting replacement windows?
The window frame in which an insert is to be replaced should be structurally sound, not soft, not rotten or damaged by water, reasonably square (not racked or bowed) and be clear of moisture leakage. This will be determined by a qualified installer at the in-home measurement visit. Partial repairs may sometimes be possible before the insert is placed onto the frame if there are soft spots or slight damage in certain parts of the frame. A full frame replacement – or even a new construction approach – will be suggested for extensive or structural damage.
Q: What window styles are available as replacement windows in Toronto?
Replacement windows come in all of the major styles that include casement, double-hung, sliding, awning, fixed picture windows, bay and bow, specialty windows and more. Based on ventilation requirements, architectural style and the size of the existing rough opening, you can choose a style. A good Toronto window company will have these arrangements in both insert and full frame replacement windows.