Picking the right windows for your home takes more thought than most people expect. Get it wrong and you could end up with rooms that are cold in January, hard to ventilate in summer, or windows that simply look out of place on your street. Two styles that come up again and again for Dublin homeowners are vertical slider windows and casement windows – and both are worth a proper look before you decide.
This guide goes through what each window type actually does, where it works well, and how to figure out which one fits your home.
What Are Vertical Slider Windows?
Vertical slider windows – also called sash windows – open by sliding one pane up over the other. The style dates back to Georgian and Victorian times, which is why you still see them on older Dublin streets in Rathgar, Drumcondra, and Clontarf.
They are not just for period homes, though. Modern vertical sliders work well in new builds too. The main appeal is the slim frame, the tall proportions, and a look that fits in naturally on most streets without drawing attention to itself.
Key Features of Vertical Slider Windows
- Dual sash operation – both the top and bottom panels slide, giving you good control over how much air comes in and where
- No outward swing – they don’t open into the garden or walkway, so they work well in tight spots
- Stack ventilation – opening the top and bottom sash together lets warm air out through the top and brings cooler air in at the bottom
- Double or triple glazing – for better U-values and lower heat loss through the glass
- Choice of materials – wood, uPVC, aluminium, or fibreglass depending on your budget and the look you’re after
- Low day-to-day maintenance – modern frames hold up well against Irish rain and wind without much attention
👉 Want to see them before you buy? Request a free quote and come into our Swords or Rathgar showroom to see vertical slider windows in person.
What Are Casement Windows?
Casement windows are hinged at the side and push open outward, either left or right. They have been the most commonly fitted window style across Ireland for decades – partly because they open fully, partly because they close very tightly, and partly because they work in almost any room type.
ThermoGlaze’s casement range uses a multi-chambered profile and is available in Elite 70 Sculptured and Elite Chamfered frames. Every window leaves the factory with hinge claws and a multi-point shoot bolt lock fitted as standard.
Key Features of Casement Windows
- Full outward opening – the whole pane swings out, which means you get good airflow and a clear view
- Multi-point locking – hinge claws and shoot bolt locking come fitted as standard on every unit
- Four glazing options – you can choose the level of acoustic and thermal performance that suits your room
- Tight close when shut – the frame seals well against the draught bar, which keeps draughts out and heat in
- Simple to open – the crank mechanism is easy to use, even for older family members
- Fits most room types – kitchens, living rooms, bedrooms, bathrooms – casement windows work in all of them
For Dublin homeowners working on their BER rating, the close seal on a casement window is one of the more practical ways to cut heat loss without a major renovation.
Vertical Slider vs Casement Windows: Side-by-Side
Here is how both window styles sit against each other on the things that matter most when you’re buying windows in Ireland:
| Feature | Vertical Slider Windows | Casement Windows |
| Opening Mechanism | Slides vertically | Hinges outward to the side |
| Ventilation | Good – top and bottom venting | Very good – full panel opens |
| Space Needed Outside | None | Yes – needs room to swing out |
| Best For | Period homes, street-facing rooms | Most room types, new builds |
| Look | Traditional, classic sash | Works on both older and modern homes |
| Security | Good with modern locking hardware | Strong – multi-point locking fitted as standard |
| Energy Efficiency | Good with double/triple glazing | Very good – tight close seal |
| Glazing Options | Double or triple | Four options available |
| Maintenance | Low | Low |
| Ideal Dublin Areas | Rathgar, Drumcondra, Clontarf etc | Suitable across all Dublin areas |
Which Window Type Is Better for Period Homes?
If your home was built before the 1970s – think red-brick semis in Drumcondra, Victorian terraces in Rathgar, or Edwardian houses in Clontarf – vertical slider windows are generally the more sympathetic choice. The sash profile matches the original character of these properties and, in some conservation areas, may even be the required style.
That said, ThermoGlaze casement windows can be specified with traditional-looking frames that sit well on older homes too. It really comes down to what your planning conditions allow and what look you want to achieve.
Which Window Type Is Better for New Builds?
For new builds and extensions across Dublin, casement windows tend to be the go-to. They are quicker to install, easier to source in a wide range of sizes, and their outward-opening design maximises the amount of fresh air you can get into a room. If your new build faces onto a garden or open space – where there is no obstruction outside the window – casement windows are hard to beat for practicality.
👉 Planning a new build or extension in Dublin? Call us on 01 912 0600 to talk through your window options with our team.
Ventilation: A Closer Look
Both window types ventilate well, but they do so differently.
Vertical slider windows create what is called a cross-ventilation or stack effect. If you open the bottom sash a few inches and tilt the top sash down slightly, warm stale air escapes from the top while cooler fresh air enters at the bottom. This is particularly useful in bedrooms and living rooms where you want airflow without a strong draught.
Casement windows, when fully open, allow the entire pane area to act as an air intake. They tend to catch wind from the side, which makes them very effective in rooms that need strong, direct ventilation – like kitchens or bathrooms.
Security: What to Expect From Each Style?
Security is something no Dublin homeowner should compromise on.
ThermoGlaze casement windows come with hinge claws and a multi-point shoot bolt locking system fitted as standard – a strong baseline for home security.
Vertical slider windows, when fitted with modern locking hardware, are also secure. The sliding mechanism is inherently difficult to force from outside, and contemporary vertical sliders include multi-point locks and restrictors as standard features.
Both window types can be specified with laminated or toughened glass for additional security if needed.
Energy Efficiency and SEAI Grants
Whichever style you choose, the glazing specification matters as much as the frame. Both vertical slider and casement windows from ThermoGlaze are available with double or triple glazing to achieve low U-values and meet current building regulations.
If you have single glazed windows in your Dublin home, you may qualify for help under the SEAI grant scheme which helps pay for upgrading to more energy efficient windows. This is true of both casement and vertical slider window replacements so it’s worth checking your eligibility before you decide on either one.
Maintenance: How Do They Compare?
Neither window type requires a great deal of maintenance when fitted with quality materials.
- Vertical slider windows in uPVC or aluminium need little more than a periodic wipe-down of the frame and tracks. Timber frames require occasional repainting or restaining.
- Casement windows are similarly low-effort – the hinges and locking mechanism should be lubricated annually, and the frame cleaned as needed.
Both will give you many years of reliable performance when installed correctly by an experienced team.
Which Window Should You Choose?
The honest answer is: it depends on your home. Here is a quick guide to help you decide:
Choose vertical slider windows if:
- You have a period property or a home with traditional character
- You want street-facing windows that don’t swing outward
- You like a classic sash look with modern performance
- Space or planning restrictions prevent outward-opening windows
Choose casement windows if:
- You are building new or fitting out an extension
- You want maximum ventilation and full-panel opening
- You need strong security as standard
- You want four glazing options to tailor thermal and acoustic performance
Still unsure? The best thing to do is visit one of our Dublin showrooms and see both styles in person. Our team will guide you through the options specific to your individual home and location.
Conclusion
Both vertical slider and casement windows are strong, practical choices for Dublin homes – they just suit different situations. Vertical sliders bring character and heritage appeal, making them a natural fit for older properties across areas like Rathgar, Clontarf, and Drumcondra. Casement windows offer full ventilation, tight sealing and built-in security, making them a reliable workhorse for modern homes and extensions across all parts of Dublin.
At ThermoGlaze, we supply and install both styles across Dublin, and our team is on hand to help you make the right call for your home. Whether you are replacing old windows or fitting out a new build, we will give you honest advice and a competitive quote with no pressure.
📞 Call us today on 01 912 0600 🌐 Visit us at ThermoGlaze.ie
Our Showrooms
Northside – Swords: Unit F2, Swords Enterprise Park, Feltrim Road, Drinan, Swords, Co. Dublin, K67 WF72
Southside – Rathgar: 68 Rathgar Avenue, Dublin 6, D06 KN53
Both showrooms are open for walk-in visits. Come and see our full range of windows on display before you decide.
FAQs
1. What is the difference between a vertical slider window and a casement window?
A vertical slider window (also called a sash window) opens by sliding one pane upward over the other. A casement window is hinged at the side and opens outward like a door. Both offer good ventilation and energy efficiency, but they suit different home styles and room positions.
2. Are vertical slider windows good for Irish homes?
Yes. Vertical slider windows are well suited to the Irish climate, particularly for period properties. Modern versions come with double or triple glazing and durable frames that handle rain and wind reliably.
3. Do casement windows have better security than vertical sliders?
ThermoGlaze casement windows come with hinge claws and multi-point shoot bolt locking as standard, which is a strong security specification. Vertical slider windows fitted with modern multi-point locks are also secure. Neither style is significantly weaker than the other when properly specified.
4. Can I get SEAI grant funding for either window type?
Yes. Both vertical slider and casement windows can qualify for SEAI grant support when they meet the required energy performance standards. Contact ThermoGlaze to confirm eligibility for your property.
5. Are vertical slider windows more expensive than casement windows?
The two styles sit at different price points depending on material, size, and glazing specification. Contact our team for a tailored quote based on your specific requirements.
6. Which window type is better for a Victorian or Edwardian home in Dublin?
Vertical slider windows are generally the better fit for Victorian and Edwardian homes, as the sash profile matches the original architectural character of these properties. Some conservation areas may require this style.
7. Do casement windows need a lot of space outside to open?
Yes. Because casement windows swing outward, you need clearance on the outside – typically at least the full width of the open panel. They are not suitable for positions directly above patios, decking, or narrow walkways where the swing would be obstructed.
8. What glazing options are available with casement windows from ThermoGlaze?
ThermoGlaze casement windows offer four distinct glazing options, providing varying levels of acoustic and thermal insulation. Triple glazing is available for maximum energy performance.
9. Can vertical slider windows be made in aluminium or uPVC?
Yes. ThermoGlaze vertical slider windows are available in a range of materials including wood, vinyl (uPVC), aluminium, and fibreglass – so you can match the frame material to your home’s requirements and budget.
10. How do I get a quote for windows in Dublin?
Call ThermoGlaze on 01 912 0600 or request a free quote online. You can also visit our showrooms in Swords or Rathgar to see the full range in person before making any decision.