By Wellington Glass & Mirror
If you are considering retrofit or replacement double glazing for your Wellington home, one of the first questions often asked is about cost. The honest answer is that prices vary depending on the type and state of your existing windows, the solution chosen, and the level of performance you want from your upgrade.
This guide aims to explain common things that affect double glazing costs in Wellington, to provide realistic price ranges, and to help you decide what makes most sense for your home and budget.
What Affects the Cost of Double Glazing?
Several key factors influence the overall cost of double glazing in Wellington.
Your Existing Window Frames
- Timber windows can be either retrofitted with double glazing or replaced with new double-glazed timber sashes or aluminium inserts. In both cases the original timber surround fitted into the wall of your house, into which the timber joinery is fitted, remains in place and the wall cavity and weather sealing around your windows and doors are undisturbed, reducing cost.
- Retrofitting replaces single glass with modern double-glazing units, refurbishing your existing timber sashes.
- If your old timber sashes are in poor condition, these can be replaced with new double-glazed timber sashes or aluminium inserts, fitted inside your existing timber surrounds.
See Aluminium Insert vs Timber Retrofit Double Glazing — Which One Is Right for Your Home? to find out more.
- Aluminium windows can also be retrofitted with new modern double glazing, again retaining the existing aluminium surrounds fitted into the wall of your house to minimise cost and disruption.
Retrofit vs Full Replacement
Retrofit double glazing is typically the most cost-effective option when you want to retain your existing window and door layout. See our post on What is Retrofit Double Glazing? to find out more.
If you want to completely upgrade your joinery or substantially change the function and layout of your windows and doors, then all new aluminium joinery is recommended. This is referred to as Full Replacement and is substantially more expensive.
Learn more here about Double Glazing Options
Window Type
Costs of double glazing also vary with window type:
- Opening windows are typically more expensive than similarly-sized fixed windows
- Glass in doors is often more expensive than glass in windows
- Double-hung windows that slide up and down counterbalanced by weights, are more expensive than standard windows
- Refurbishing and retaining leadlights adds significant cost
- Retaining colonial bars also adds cost
- Round or shaped windows are more expensive than rectangular windows
Glass Type and Performance Level
Not all double glazing is the same. High performance glass options can improve:
- Thermal insulation
- Noise reduction
- Solar control, reducing excessive solar heat gain, glare, UV light and furniture fading
- Condensation resistance
Using double glazing, we can combine different grades and types of glass, spacer and gas-fill to create units of very different thermal efficiency and ability to let light, heat, sound and radiation causing fading into your home, as well as to markedly reduce condensation and heat loss.
High performance or tinted glass typically adds 5-10% more to the overall cost upfront but delivers substantially greater comfort and energy efficiency over time.
Window Location, Size, Access, and Wind Load
The location in your home and height of your windows above ground or floor level influence the need for increased glass thickness or safety glass. For example, safety glass is required in bathrooms and close to stairs or stair landings, and in low-level windows, particularly if they are elevated above ground level outside. The need for thicker glass or safety glass increases cost.
Likewise, large windows, hard-to-access areas and multi-story homes typically require more labour and equipment, which also increases costs.
Wellington is also known for its beautiful harbour, hills and wind! Large windows in high wind zones require thicker and heavier glass to safely withstand exposure to high wind. This adds to both the glass and labour costs, particularly if access to the windows is difficult.
Conversely, a standard single-level house with typical casement or awning windows at or above hip height is likely to cost less.
Number of Windows
Doing a whole house or multiple rooms at one time is usually more efficient for the manufacturer and installers, and the cost savings can be passed back to you. As a rule, the more windows you upgrade at the same time, the lower the cost per window.
Material and labour costs also increase over time, so delaying double glazing or deferring some of your project to a later time can result in increased costs overall. Taking advantage of zero- or low-interest bank loans or other finance options to double glaze as much of your home as you can at one time, combined with energy savings, may save you money in the long run.
Average Cost of Double Glazing in Wellington
In calculating typical costs, we refer to a “window” as a single pane of glass or double-glazing unit.
As a general guide, most Wellington homeowners can expect prices (including GST):
- Timber retrofit double glazing: From about $800 to $1,200 per window
- Timber replacement sash double glazing: From about $850 to $1,250 per window using the RetroGlaze® system
- Aluminium retrofit double glazing: From about $550 to $850 per window
- Aluminium insert double glazing: From about $980 to $1480 per window
- Full replacement aluminium windows and doors: From around $1,500 to $2,500+ per opening.
These are indicative ranges only. Final pricing depends on all of the factors mentioned above including window size, type, access, glass specification, and the condition of your existing joinery.
Cost Expectations for Typical Wellington Homes
To make double glazing costs more relatable, it helps to look at realistic examples using an online estimate tool.
As a general guide, Wellington homeowners can expect:
- Small home or apartment (5–10 windows): Around $6,000 to $10,000 for retrofit double glazing
- Standard family home (10–20 windows): Around $10,000 to $18,000 depending on glass performance and scope
- Larger villas or character homes: $19,000+ depending on window sizes, timber condition, access, and detailing
The RetroGlaze Double Glazing Cost Calculator allows you to estimate ballpark costs based on window numbers, sizes, and glazing type.
Wellington Glass & Mirror is the RetroGlaze certified partner for the Wellington region, installing timber and aluminium retrofit and replacement systems that meet strict performance and quality standards.
Online estimates are a helpful planning tool, but every home is different. Factors such as frame condition, access, glass performance upgrades, and custom detailing all influence final pricing.
A site consultation and assessment is recommended to provide accurate advice and pricing options.
Is Double Glazing Worth the Investment in Wellington?
Wellington’s climate makes double glazing a very worthwhile investment for most homeowners. Benefits include:
- Warmer, more comfortable living spaces
- Reduced condensation and dampness
- Noticeable noise reduction
- Improved energy efficiency & savings on energy bills
- Added value and appeal to your home
While double glazing is an upfront investment, many homeowners find the improvement in comfort and livability makes it a very worthwhile investment.
To learn more, see our post on The Benefits of Retrofit Double Glazing Your Home
Can You Double Glaze Your Home in Stages?
Yes. Many Wellington homeowners choose to upgrade in stages, starting with:
- Bedrooms
- Living areas
- The coldest or noisiest rooms
Staged upgrades allow you to spread costs over time while still seeing immediate benefits.
However, staging can result in higher total costs, for the reasons discussed above.
How to Get an Accurate Cost for Your Home
The most reliable way to understand double glazing costs is through a professional consultation and assessment of your home. This allows us to:
- Understand your needs, budget and priorities
- Measure and assess your existing joinery and windows
- Tailor options to your home and needs
- Recommend specific retrofit or replacement options
- Provide accurately costed options in a clear and easy to read proposal
At Wellington Glass & Mirror, we focus on finding the right solution for your home, tailored to your needs and budget. We offer a complete range of retrofit and replacement options, backed by retroGLAZE® systems and technologies and the Window & Glass Association NZ code of ethics and standards.
Frequently Asked Questions About Double Glazing Costs in Wellington
As a general guide, double glazing costs in Wellington typically range from: $550 to $850 per window for aluminium retrofit; $800 to $1,200 per window for timber retrofit; $980 to $1480 per window for aluminium inserts; and $1,500 to $2,500+ per opening for full replacement windows or doors. Final pricing depends on window size, location, access, glass performance, and the condition of existing frames.
Yes. Retrofit double glazing is usually more cost-effective when existing frames are in good condition. It allows you to keep your current joinery while significantly improving warmth, comfort, and noise reduction. Full replacement is recommended when frames are failing or when changing layouts or adding new doors.
Yes. The RetroGlaze® Double Glazing Cost Calculator provides a helpful starting estimate based on window numbers and types. Wellington Glass & Mirror is the certified RetroGlaze® partner for the Wellington region and can confirm accurate pricing following an on-site assessment.
Yes. Double glazing helps reduce heat loss, condensation, and noise, making homes warmer, drier, and more comfortable year-round. Many homeowners also see improved energy efficiency and increased property appeal.
Absolutely. Many homeowners choose to start with bedrooms or living areas and upgrade other rooms over time. Staged upgrades help spread costs while still delivering noticeable comfort improvements.
Double glazing can significantly reduce condensation caused by cold glass surfaces. However, good ventilation and moisture management are still important. During your consultation, we can help identify the best solution for your home.
Thinking About Double Glazing?
If you are considering double glazing in Wellington and want realistic advice on prices and options, our team are happy to help.
