Retrofit Double Glazing for Timber Framed Windows
We are licensed installers of Thermawood, the most advanced retrofit double glazing system for windows with wooden framing.
The Thermawood system
Double glazing without new frames
Save yourself the major expense of fitting new windows and timber framing. With a Thermawood conversion, we only need to replace the glass. It’s a simple procedure that works with casement, double-hung or fixed windows. You get all the benefits of double glazing and the character of your home is maintained.
We remove the single glazed glass from your existing window and create a 15-degree slope in the bottom of the frame. Then we install the patented drainage system that holds the draft and acoustic seal and double glazing in place, and the window beading specially designed to let maximum moisture escape.
Watch the video to find out how it works:
Thermawood double glazing benefits
- We will complete your retrofit on site. There will be no need to board up windows – what comes out goes back in the same day.
- 100% New Zealand made, designed for local conditions – helps keep your house warm in winter and cool in summer.
- Retains the look and function of original windows, including double-hung sash windows and heritage windows with leadlights.
- Used successfully in thousands of conversions.
- Installation allows moisture to escape while excluding draughts and noise.
- Cost-effective compared with alternatives, and you’ll save on heating and cooling costs.
- Special glass options available for extra insulation (argon gas), safety, noise reduction and UV blocking (low-E glass).
The result: a warmer, drier, quieter and healthier home.
Mike's Glass is a Thermawood licensed installer.
Our retrofit double glazing warranty
Every installation is backed by warranties that let you enjoy the results in complete peace of mind.
Lifetime
on our workmanship
on powder coat finish
on hardware
on double glazed units
Flexible pricing
'Pay by the room' double glazing offer
This allows us to complete the double glazing of your existing windows in stages, as and when you can afford it.
There is no need, or expectation, for all the work on your house to be completed at the same time in one job.
We can work at your home every few months or when you have the budget. We will start with south-facing windows, and continue from there at a pace that suits you.
Can all wooden windows be retrofitted with double glazing?
Yes, 99% of the time. We can retrofit casement, double hung and fixed windows. We will come and give you a written initial assessment of your windows to ensure they are suitable to be retrofitted.
If my wooden windows are rotten, should I choose aluminium instead?
Wood is a better insulator than aluminium, so it is preferable to repair the wooden windows or replace them with new wooden frames. Your windows will be assessed during the initial quote so you can arrange any necessary carpentry. If hidden rot is found when we rebate the windows, we’ll let you know and discuss your options with you.
If I have leadlight windows, can I keep the leadlights?
Yes, the Thermawood system allows us to protect the leadlight by installing a new border lead and resealing the leadlight before installing it into the new double-glazed unit.
Will my double-hung windows stay up once the double glazing has been retrofitted?
Yes. To ensure smooth operation, we weigh the sash with the double glazing installed and re-weight the double hung windows accordingly.
Is the work done on site?
If possible all the work is done on site. We will remove the windows, rebate the frames and fit the double glazing and then refit in the windows on the same day.
Do you paint the windows after the job is complete?
We don’t generally paint as we find most people like to do this themselves or engage their own painter. We will leave the window ready to be painted, with primed timber and all pin holes filled.
Can I keep my original handles and openers?
Yes, if everything is still working and in good condition and we can retrofit it, then we will reinstall your original hardware. Otherwise we can recommend new options.
Why should I choose the Thermawood system?
It’s the only system with a special drainage adapter to prevent excess moisture building up, giving you better, longer-lasting results. All Thermawood systems have been tested to, and passed New Zealand Standard 4211 which covers weathertightness and the ability to withstand high winds. With a commitment to sustainability, the Thermawood system uses recycled or sustainably sourced components where possible.