Planning a window upgrade
Retrofit vs full replacement in Perth
Updated
Penot installs complete new frames and glazing. Compare the scope before choosing how to upgrade your existing windows.
Penot installs complete replacement windows: new frames and new glazing. We do not retrofit double-glazed units into your existing frames. If you are searching for retrofit double glazing in Perth, first check what each supplier means by the term. Some use it for replacing glass within an old frame; others use it more broadly for upgrading windows in an existing home.
What is the difference?
| Question | Glass replacement in an existing frame | Complete window replacement |
|---|---|---|
| What stays? | The existing frame, where the proposed glass and frame are compatible. | The surrounding opening may remain, but the window frame and glazing are replaced. |
| What needs assessment? | Frame condition, rebate dimensions, hardware and capacity for the new unit. | The opening, frame configuration, glazing, access and installation details. |
| What changes visually? | It depends on the glazing system and any alterations to the old frame. | Frame profiles, sightlines and opening style may change. |
| Does Penot provide it? | No. | Yes, subject to assessment and any necessary approvals. |
Why Penot fits a complete new frame
A complete replacement lets us specify the frame, glass, seals and hardware together. It also allows the opening style to be reconsidered where the site and design permit. Penot supplies thermally broken aluminium windows as standard, with styles including tilt and turn, casement, awning, sliding, stacking, arched and curved windows.
This does not mean every existing frame should be removed. Original joinery may have heritage significance, and a frame in good condition may be worth retaining. If keeping the old frame is essential, our complete replacement service may not be the right fit. Get advice appropriate to the property before deciding.
What affects performance?
Double glazing is one part of a window system. Frame design, glass specification, seals and installation also affect the finished result. Ask for performance data that applies to the proposed complete unit, rather than assuming all double glazing performs alike.
If noise is the main concern, tell the supplier what you hear, which rooms are affected and when it matters most. If summer heat is the priority, discuss orientation and shading as well as the glass. Avoid treating a single laboratory rating as a promise for the whole room.
Compare the full installation scope
Two quotes may cover different work even when both use the phrase “double glazing”. Ask each supplier to identify:
- The frame and glass configuration for each opening.
- The opening direction, clear access and hardware.
- Removal and disposal of the existing windows.
- Internal and external finishing around the new frames.
- Any structural work, approvals or other trades excluded from the price.
- Separate warranty terms for frames, glass, hardware and installation.
How much does full replacement cost?
The quote depends on dimensions, shape, glazing, frame finish, access and the work around the opening. A glass-only price cannot be directly compared with a complete replacement price. Penot needs a site assessment and agreed scope to provide an accurate project quote.
Use our Perth double glazing cost guide for planning context, then compare written quotes for the same specification and inclusions.
What about heritage homes?
Check the property’s heritage status and any requirements before ordering. Replacing an original window may be unsuitable or require approval. Penot does not promise that a new aluminium frame will exactly reproduce original timber joinery. Read our guide to double glazing for heritage homes and seek property-specific advice.
Frequently asked questions
Can I keep the existing opening?
Often the project is planned around an existing opening, but its dimensions, condition and installation requirements need assessment. Keeping the opening is different from keeping the old window frame.
Does Penot offer glass-only replacement in old frames?
No. Penot supplies and installs complete new frames and glazing. Make that scope clear when comparing quotes.
How long will the project take?
Penot’s current general lead time is 6 to 14 weeks. Confirm the timing for your configuration and installation when ordering; project requirements can affect the schedule.
What warranty applies?
Every Penot installation carries a 10-year frame warranty. Ask for the written terms and separate cover for glass, hardware and installation.
Plan your replacement windows
Compare our double glazed window styles, visit the Bayswater showroom or request a site assessment. Bring photographs or plans and explain what you want to improve so we can assess the opening and quote the complete work.