Casement windows vs french windows
James Elston

James Elston

Published March 16, 2025

Last Updated on March 17, 2025

French Windows vs Casement Windows: Which Is Better For Your Home?

When choosing new windows for your home, the decision between French windows and casement windows can be challenging. Both styles offer unique benefits, impacting aesthetics, insulation, security, and functionality. 

Whether you are a homeowner or landlord in the UK looking to upgrade your windows, this guide will provide an in-depth comparison to help you make the right choice.

French Windows vs Casement Windows: A Quick Comparison

FeatureFrench WindowsCasement Windows
Aesthetic AppealElegant, traditional lookVersatile, suits modern and traditional homes
Opening MechanismOpens fully without a central mullionSingle unit with a side hinge
VentilationMaximum airflow due to full openingModerate airflow, depends on window size
Energy EfficiencyCan be less efficient due to larger opening gapsOffers excellent insulation and weatherproofing
SecurityCan be vulnerable if not properly lockedGenerally secure with multi-point locking systems
CostTypically higher due to double panelsMore affordable
Best Suited ForTraditional homes, large openings, patiosModern and traditional homes, smaller windows

French Windows vs Casement Windows: Key Differences?

French Windows

French windows consist of two outward-opening panels that meet in the middle without a central mullion, providing a completely unobstructed view when opened. They function similarly to double doors, making them ideal for balconies, patios, or large window openings.

These windows typically have:

  • Side-hinged mechanisms that allow both panels to open wide.
  • A central handle that operates the primary locking system.
  • A secondary shoot bolt lock on the inactive panel for security.

French windows are commonly used in traditional and period-style homes due to their classic aesthetic. However, they also work well in modern properties where homeowners want seamless indoor-outdoor transitions and ample ventilation.

Pros and Cons French Windows

Pros
  • Maximum opening space
  • Elegant and stylish appearance
  • Ideal for ventilation and large openings
Cons
  • Higher cost
  • Less energy-efficient
  • Requires more space to open fully

Casement Windows

Casement windows are single-panel windows that open outward using side hinges. They are highly versatile and suitable for all types of homes, from contemporary properties to traditional cottages.

Key features include:

  • A single sash that swings outward, usually operated by a crank handle or push-out mechanism.
  • Multi-point locking systems for enhanced security.
  • The option to be top-hung (opening from the bottom) or side-hung (opening from the side).

Casement windows provide excellent insulation and draught resistance due to their tight-sealing design, making them an energy-efficient choice for UK homes.

Pros and Cons Casement Windows

Pros
  • Excellent insulation and energy efficiency
  • Lower cost
  • Secure and durable
Cons
  • Limited opening compared to French windows
  • Can obstruct views slightly

If you’re debating between casement and other window types, you may also want to explore comparisons like casement vs double-hung windows or casement vs sliding windows, as these styles offer different functionality and aesthetic benefits.

Which Property Types Are Best for French or Casement Windows?

Choosing between French and casement windows depends on the style, layout, and requirements of your property.

Best Properties for French Windows

  • Traditional & Period Homes – Their classic design complements Georgian, Victorian, and Edwardian homes.
  • Homes with Large Openings – Ideal for patios, balconies, and garden-facing rooms where an unobstructed view is desired.
  • Luxury & High-End Properties – Often found in premium homes to create a grand and elegant look.
  • Properties with Good Exterior Space – Since they open outward, French windows are better suited for homes with enough clearance outside.

Best Properties for Casement Windows

  • Modern & Contemporary Homes – Their sleek design works well with new builds and modern architecture.
  • Homes in Windy or Noisy Areas – The tight seal helps with soundproofing and draught resistance.
  • Smaller Homes & Flats – Casement windows take up less space when open, making them perfect for compact properties.
  • Energy-Efficient Homes – Their superior insulation makes them a preferred choice for reducing heat loss.

For period-style properties, sash windows are another alternative to casement windows, offering a vertical sliding mechanism that maintains a classic appearance while still allowing for ventilation.

French vs Casement Window Materials

Both French and casement windows come in a variety of materials:

  • UPVC Windows: Affordable, low maintenance, and energy-efficient.
  • Aluminium Windows: Sleek, modern, and highly durable.
  • Timber Windows: Classic appeal, but requires more maintenance.

View & Natural Light

  • French windows offer an uninterrupted view due to the absence of a central frame.
  • Casement windows provide a clear view but may have a central mullion in larger designs.
  • French windows allow more light when fully open, whereas casement windows provide good light intake even when closed.

Insulation & Energy Efficiency

  • Casement windows offer better thermal insulation, as they seal tightly when closed.
  • French windows may be less energy-efficient due to larger openings and potential draughts.

When considering long-term performance, the way a window sits within the frame impacts insulation and weather resistance. Flush windows create a tighter seal, reducing drafts, while casement windows use compression seals that enhance energy efficiency in a different way. 

If you’re weighing up the pros and cons of each, our detailed comparison of flush windows vs. casement windows breaks down their performance, costs, and benefits to help you decide.

Glazing Options

Both can be upgraded with double or triple glazing for improved efficiency.

Glazing TypeFrench WindowsCasement Windows
Double GlazingGood insulation & noise reductionStandard for high energy efficiency
Triple GlazingBest insulation but heavierIdeal for high-performance homes
Low-E GlassReduces heat lossImproves energy efficiency
Acoustic GlassMinimises outside noisePopular in urban areas

Ventilation & Draughts

  • French windows offer superior ventilation due to full opening capability.
  • Casement windows allow for controlled airflow but can direct air efficiently when angled.
  • Casement windows are less prone to draughts compared to French windows

For homeowners looking for superior rain protection while still allowing ventilation, awning windows could be a practical alternative to casement windows, as they open outward from the top and provide airflow even during wet conditions.

Read our guide on awning vs casement windows for an in-depth comparison. 

Security Features

  • Casement windows generally provide better security due to their multi-point locking systems.
  • French windows can be secured with shoot bolt locks but may be vulnerable if not locked correctly.
  • Both options can be fitted with laminated glass for extra protection.

Maintenance & Longevity

Both French and casement windows require routine maintenance, but their upkeep differs due to their design, hinges, and locking mechanisms.

Maintenance FactorFrench WindowsCasement Windows
CleaningCan be harder to clean due to sizeEasier to maintain
Wear & TearHinges may require regular checksLower wear due to tight seal
LongevityDurable if maintained wellGenerally lasts longer with less upkeep

  • French Windows require more frequent maintenance, especially if they are made from timber. The dual-panel mechanism means that hinges, locks, and seals need to be regularly checked for wear and tear. UPVC and aluminium French windows require less upkeep than timber options.
  • Casement Windows are generally easier to maintain as they have fewer moving parts. Since they seal tightly when closed, they are less prone to draughts and water ingress, which can lead to longer-lasting frames and hardware.

French windows, while durable, may require occasional adjustments to their locking and hinge mechanisms to ensure smooth operation over time

Casement windows generally have a longer lifespan due to their weather-tight design and reduced exposure to external elements when closed. 

Security and ease of maintenance are important factors when choosing the right window style. Casement windows offer strong locking mechanisms and a simple outward-opening design, making them a secure and reliable choice. 

However, for homeowners looking for added functionality, tilt and turn windows provide an alternative with multi-point locking and an inward opening feature that makes cleaning from the inside effortless. To see how these two styles compare, check out our in-depth guide on casement windows vs. tilt and turn windows.

Costs & Installation

The cost of French windows tend to be more expensive than casement windows due to their dual-panel structure and increased material usage. 

The cost of casement windows, especially UPVC options, are generally more affordable and offer better energy efficiency for the price.

Window TypeUPVCAluminiumTimber
Casement Windows£350 – £750£600 – £1,000£800 – £1,500
French Windows£750 – £1,200£1,000 – £1,800£1,500 – £2,500

Note: Average Cost (Per Window, Installed)

  • UPVC casement windows are the cheapest option, offering a great balance between cost, insulation, and durability.
  • Aluminium French windows are among the most expensive, due to their dual-panel construction and high-quality metal frames.
  • Timber windows, regardless of type, are typically the costliest due to the material and maintenance requirements.

If the cost of new windows is a major factor for your budget, casement windows—particularly in UPVC or aluminium—offer better value for money compared to French windows.

Installation Requirements & Timeframe

The installation of French and casement windows varies depending on the property type, window material, and structural requirements.

French Window Installation
  • Requires wider openings to accommodate dual-panel frames.
  • May need reinforcement around the window opening, especially in older homes.
  • Additional work may be needed to ensure secure locking mechanisms.
  • Installation can take 3–6 hours per window, depending on size and complexity.
Casement Window Installation
  • Requires less structural modification, making it easier and quicker to install.
  • Standard casement windows can be installed in 2–4 hours per window.
  • Less labour-intensive than French windows, reducing overall installation costs.
Which Window Type Is Easier to Install?

Casement windows are generally quicker and simpler to install due to their single-panel design and minimal structural adjustments. French windows, however, require more precise installation to ensure both panels align correctly and function smoothly.

French vs Casement Window: Which Window Type Is Best for Your Home?

  • Choose French windows if you want a traditional aesthetic, maximum ventilation, and unobstructed views.
  • Choose casement windows if you prefer better insulation, security, and affordability.
  • Consider glazing options and frame materials to match your home’s style and energy needs.

Get a Free Quote for New Windows Today!

If you’re considering French or casement windows for your home, get a free, no-obligation quote today! Our team of expert window installers will help you find the best option to suit your budget and property needs.

FAQs

Are casement windows old-fashioned?

No, casement windows are not old-fashioned. While they have been used for centuries, modern designs incorporate sleek frames, energy-efficient glazing, and multi-point locking systems, making them a popular choice for contemporary and traditional homes alike.

What is the difference between French and casement windows?

French windows are double-panel windows that open outward from the middle without a central frame, providing an unobstructed view. Casement windows are single-panel windows that open outward on side hinges, offering better insulation and weatherproofing.

Are casement windows out of style?

No, casement windows remain one of the most popular window styles in the UK due to their excellent ventilation, energy efficiency, and security features. They suit both modern and traditional homes and are available in various materials and finishes.

Can French windows be double glazed?

Yes, French windows can be double glazed for improved insulation, noise reduction, and energy efficiency. Many homeowners opt for double or even triple glazing to enhance their home’s warmth and security.

What do French windows look like?

French windows consist of two side-hinged glass panels that open outward, similar to French doors. They often have a classic, elegant design, making them ideal for traditional and period properties.

Why do people like casement windows?

Casement windows are popular because they offer superior ventilation, excellent insulation, and enhanced security. Their tight-sealing design makes them energy-efficient, reducing heat loss and draughts in UK homes.

Do French windows need planning permission?

In most cases, French windows do not require planning permission unless you live in a listed building, conservation area, or are making major structural changes. Always check with your local planning authority if unsure.

Are French windows secure?

Yes, modern French windows come with multi-point locking systems, toughened glass options, and reinforced frames to improve security. However, they can be less secure than casement windows if not properly locked or fitted with security upgrades.

James Elston

James Elston

Boiler Expert

James Elston is the top boiler replacement and heating expert at Eco Happy. He has over 20 years of experience in the industry, focusing on Gas Safe boiler installations and offering home-heating and energy-saving solutions to homeowners across the UK. From sourcing the most energy-efficient combi boiler to providing specialist heating advice, James ensures that Eco Happy maintains the highest standards and best customer service.

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