Windows and Doors: What You Need to Know Before You Buy

A concise guide to frame materials, glazing options, energy ratings, and what to check before committing to a window or door replacement. ## Frame Materials at a Glance **uPVC** remains the most popular choice in the UK — affordable, low-maintenance, and thermally efficient. Modern uPVC achieves U-values of 1.2–1.4 W/m²K as standard.

**Aluminium** suits contemporary designs with slim sightlines. It is inherently strong, allowing larger glass areas, but typically costs 30–50% more than uPVC. **Timber** offers a traditional aesthetic and excellent thermal performance but requires periodic maintenance (repainting every 5–8 years). **Composite** frames combine materials — typically a timber core with an aluminium or uPVC exterior — for reduced maintenance with a premium finish.

## Glazing: Double vs Triple Double glazing is sufficient for most UK properties. Triple glazing offers marginal U-value improvement (around 0.2 W/m²K better) but at 15–25% higher cost. It is most worthwhile in exposed or north-facing elevations. Always ask for **whole-window U-values**, not centre-pane figures. ## Energy Ratings Windows are rated A++ to E.

An A-rated window is the practical minimum for most replacements in 2026. Building Regulations (Part L) require a minimum whole-window U-value of 1.4 W/m²K for replacements. ## What to Check Before Committing - Confirm the installer is FENSA or CERTASS registered - Request the whole-window U-value, not just the glass rating - Ask whether the quote includes making good (internal plastering, external sealing) - Check whether scaffolding is included or charged separately - Confirm waste removal is included - Ask about the guarantee — manufacturer vs installer warranty ## Common Mistakes 1.

Choosing on price alone without comparing specification 2. Overlooking ventilation requirements (trickle vents are mandatory under Building Regulations) 3. Not checking planning restrictions in conservation areas 4. Assuming all white uPVC frames are the same quality --- ### What to do next If you are planning to replace windows or doors, EvoHome Improvements can help you understand the right specification for the property, plan the project sensibly and, where appropriate, connect it with suitable independent installers or specialists.

EvoHome does not carry out the works directly. Start here: [/start](/start). You can also read more about how this service works at [/services/windows](/services/windows) and [/services/doors](/services/doors).