Replacing windows and doors

# Replacing Windows and Doors

Signs You Need New Windows and Doors

Before investing in replacements, know when action is necessary. Look for these warning signs:

• Drafts and air leaks — Feel cold air around frames on windy days or notice condensation between glass panes
• Difficulty operating — Windows that stick, won't lock properly, or doors that don't close smoothly
• Visible damage — Rotting frames, cracked glass, or broken seals
• Rising energy bills — Poor insulation causes heating and cooling systems to work harder
• Noise problems — Single glazing lets outside noise penetrate easily
• Age — Windows over 20 years old typically underperform modern standards

Don't replace windows purely for aesthetic reasons if they're functioning well—focus on performance first.

Material Options

uPVC (Unplasticized Polyvinyl Chloride)

uPVC is the most popular choice in the UK and Europe.

• Affordable and low-maintenance
• Won't rot, warp, or require painting
• Good insulation properties
• Long lifespan (30+ years)
• Recyclable material

• Can look plastic compared to traditional materials
• May discolor over time
• Less environmentally friendly during production
• Limited color options without additional cost

Wood

Traditional wooden frames offer timeless appeal and excellent environmental credentials.

• Aesthetically pleasing and versatile
• Excellent thermal performance when well-maintained
• Can be repaired and refinished
• Natural insulator
• Sustainable when sourced responsibly

• Requires regular maintenance (painting, sealing)
• More expensive upfront
• Vulnerable to rot, woodworm, and weather damage
• Shorter lifespan without proper care (15-20 years)
• Not ideal for exposed coastal properties

Aluminium

Increasingly popular for contemporary homes and commercial applications.

• Sleek, modern appearance
• Very durable and long-lasting
• Requires minimal maintenance
• Allows larger glass areas (slim frames)
• Excellent for large doors and glazed systems

• Poor thermal insulation without thermal breaks
• Most expensive option
• Can conduct cold, causing condensation
• Less suitable for period properties

Understanding Energy Ratings

Modern windows carry energy ratings that directly impact your heating costs.

• New standard: 1.4 W/m²K or lower
• Excellent performance: 0.8 W/m²K or lower

Solar Factor (g-value) measures how much solar heat enters through the glass. Higher values (0.6+) are good for passive solar gain in winter but problematic for overheating in summer on south-facing windows.

Whole window ratings (like energy ratings on appliances) provide an overall efficiency picture. Look for A or B ratings for best performance.

Air tightness ratings indicate how much drafting occurs. Lower numbers are better; modern windows should score under 10.

Glazing Options

Double Glazing

Two panes with an insulating air gap—the standard for most homes.

• Standard air gap: 4mm to 16mm spacer
• Argon or krypton gas fill: Denser than air, improves insulation by 15-20%
• Cost: Most affordable option

Triple Glazing

Three panes with two insulating gaps—increasingly common in cold climates.

• Benefits: Superior insulation (20-30% better than double)
• Drawback: Heavier, more expensive, and slightly reduced light transmission
• Best for: New builds, renovation projects in northern regions, or homes with severe drafts

Low-emissivity (Low-E) Coating

Invisible metallic coating reflects heat back indoors while allowing light through.

• Reduces U-values significantly
• Essential for new window installations
• Usually standard on modern units

Self-cleaning and Special Coatings

• Photocatalytic coatings break down dirt automatically
• Hydrophobic coatings cause water to bead and roll away
• These add 10-20% to the cost but reduce maintenance

Typical Costs

Prices vary significantly by region, material, and specification. Use these as rough guides:

| Material | Single Window | Glazed Door | Installation | |----------|---------------|------------|--------------| | uPVC | £250-500 | £400-800 | £75-150 per unit | | Wood | £500-1500 | £800-2000 | £100-200 per unit | | Aluminium | £400-800 | £600-1200 | £100-200 per unit |

A typical three-bedroom house with 10 windows and 2 doors might cost £4,000-12,000 fitted, depending on choices.

Installation Process

Before Installation

• Obtain multiple quotes and check installer credentials
• Verify they're registered with appropriate trade bodies
• Discuss timescales (typically 2-5 days for whole-house projects)
• Protect furniture and prepare access routes
• Confirm utility disconnect procedures (if necessary)

During Installation

• Per window: 45 minutes to 1.5 hours
• Per door: 1-3 hours

1. Remove old frames carefully
2. Clean and prepare the opening
3. Install the new frame, ensuring it's level and square
4. Apply expanding foam around gaps
5. Install glazing units
6. Add interior trim and exterior sealant
7. Test operation and locks

After Installation

• Leave silicone sealant to cure for 24 hours before cleaning
• Don't use new windows for 48 hours after installation
• Expect a warranty period (typically 10 years on units, 5-10 on installation)

Planning Permission and Building Regulations

Planning permission is usually NOT required for window and door replacement like-for-like in most areas, but there are exceptions:

• Listed buildings: Nearly always need consent
• Conservation areas: Certain materials or styles may require approval
• Flats and apartments: May require landlord/freeholder consent
• Double glazing in listed properties: Often restricted

• Proper energy standards (minimum U-value compliance)
• Fire safety compliance
• Installation quality standards

Always check with your local authority before starting work.

Security Features

Modern replacement windows and doors should include:

• Multi-point locking systems — Engage at multiple points along the frame
• Toughened or laminated glass — Resists breakage
• Restrictors on windows — Limit opening for child safety
• Anti-bump locks — Prevent forced entry on doors
• Reinforced frames — Especially on doors to exterior
• Hinge reinforcement — On outward-opening doors

Request security upgrades if you're in a high-crime area. The additional cost is usually under 5% of total project cost.

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