Written by the team at Kenny Windows & Doors. 36+ years and 5,000+ Dublin homes completed.
TL;DR
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Planning new window installation in Dublin for an extension, attic conversion or self-build means a different process to replacing existing windows. Here’s what to expect from your first call to the final walk-through, and what actually affects the price along the way.
New Installation vs Replacement: Why the Distinction Matters
New window installation fits windows into openings that don’t yet exist, built as part of an extension, a converted attic, or a new-build. Replacement removes and swaps out existing windows in an opening that’s already there. The two share some materials and suppliers, but the actual techniques differ, so it’s worth confirming a provider is genuinely experienced in new installation specifically, not just window fitting in general.
Choosing a Material for a New Opening
Most new openings in Dublin are fitted with uPVC, mainly because it doesn’t need repainting, holds heat well, and performs consistently in Dublin’s damp, changeable weather. Aluminium suits larger openings and slimmer frame lines, which is why it’s popular on contemporary extensions and bifold doors. Timber suits a period-appropriate look, at the cost of more regular upkeep.
Coordinating New Window Installation With Your Builder
If you’re working with a builder on an extension, timing matters more than most homeowners expect. Window and door openings need to be built to the exact sizes confirmed at survey stage, not estimated by the builder in advance. Sharing your window company’s measurements with your builder before any blockwork goes in avoids one of the most common snags on extension projects.
| “An opening built to the wrong size costs more to fix than it would have cost to get right the first time.” |
What a Proper Survey and Quote Should Include
- Exact measurements for every opening, confirmed on site rather than estimated from the architect’s drawings alone.
- Material and colour, stated clearly so there’s no ambiguity once the order is placed.
- Glazing specification, including any upgrade for sound insulation or a colder-facing room.
- A written installation timeframe, so you can plan around it alongside the rest of the build.
- Warranty terms in writing, not just mentioned verbally at the survey.
What Affects the Cost of New Window Installation
Rather than a single price per window, a handful of specific factors move the overall cost.
| Factor | Why It Affects Price |
| Number and size of openings | More or larger openings mean more material and labour |
| Material choice | uPVC, aluminium and timber carry different material and manufacturing costs |
| Style complexity | A standard casement window costs less than a bespoke, non-standard shape |
| Timing with the build | Openings ready and correctly sized are faster to fit than ones needing adjustment first |
| KEY POINT
Kenny Windows & Doors has used an in-house fitting team for all 36+ years of trading, with a showroom at Unit 5, Glenview Industrial Estate, Herberton Road, Dublin 12, open Monday to Friday, 9am to 5pm, for anyone who wants to see materials in person before a bigger project. |
What to Expect on Installation Day
For most homes, new window installation takes one to a few days depending on how many openings are involved. Expect dust sheets down, one opening worked on at a time where possible, and a final walk-through before the crew leaves. Dublin’s weather can affect scheduling for jobs with significant exterior work, so a reliable installer will build some flexibility into the plan rather than rushing around a forecast.
Choosing Styles for an Extension or New Build
Casement windows suit most Dublin extensions, offering a straightforward, versatile option. Tilt and turn windows are popular in bathrooms and bedrooms, since they open inward as well as outward for easier cleaning and secure ventilation. Bespoke shapes are used for anything non-standard, such as an arched opening or an unusually wide span. French doors and bifold doors are also worth considering for extensions opening onto a garden, and can usually be quoted alongside your windows at the same survey.
What to Look for in a Provider for New Installation Work
Not every window company is equally experienced in new installation specifically. It’s worth asking directly whether a provider regularly works on extensions and new builds, or whether most of their work is replacing existing windows, since the two jobs call for slightly different skills.
- In-house fitting team, so the same people who survey the job are the ones fitting it.
- Recent extension or new-build projects, not just replacement work, that they can point to.
- Comfortable coordinating with a builder, since new installation rarely happens in isolation from the rest of a build.
- A written warranty, confirmed before work starts, not just mentioned at survey.
Common Mistakes We See
- Confirming a builder’s estimated opening sizes before a proper window survey has taken place.
- Choosing a provider experienced mainly in replacement, for a job that’s actually a new installation.
- Skipping a written quote in favour of a verbal price agreed over the phone.
- Not confirming a realistic installation timeframe against the rest of the build schedule.
- Assuming every material costs roughly the same, without checking the specific style and finish chosen.
Frequently Asked Questions
What’s the difference between new window installation and replacement?
New installation fits windows into openings that don’t currently exist, typically for an extension or new build. Replacement removes and swaps out existing windows in an opening that’s already there.
How long does new window installation take in Dublin?
Most homes are completed within one to a few days, depending on the number of openings involved. Your provider will confirm a specific timeframe at survey stage.
Is uPVC a good choice for a new build or extension?
Yes, for most projects. It’s low-maintenance, holds heat well, and performs consistently in Dublin’s climate, which is why it’s the most common material chosen for new openings.
Do I need to confirm opening sizes with my builder before ordering windows?
Yes. Openings should be built to the exact sizes confirmed at your window survey, not estimated in advance, to avoid costly adjustments later.
What factors affect the cost of new window installation?
The number and size of openings, the material chosen, how standard or bespoke the style is, and how well the openings are timed against the rest of the build all affect the overall price.
In Summary
New window installation is a different job to replacement, with its own process and its own timing considerations alongside a build. Getting the survey right, confirming a written quote, and coordinating openings with your builder are what actually determine how smoothly the project goes.
If you’d like a free survey to confirm sizes and get a written quote for your extension or new build, that’s the most direct next step.