Frequently Asked Questions - Buying Windows and Doors

Start by auditing your current windows to identify what’s lacking—energy efficiency, noise reduction, ventilation, or ease of cleaning. Decide whether you need replacements or new installations, then set a realistic budget and prioritise function over looks if funds are tight. Factor in your climate (e.g., extreme temperatures call for energy-efficient options) and choose styles that suit both your home’s design and your practical needs (i.e. sliding sash for easy cleaning or casement for airflow).

Examine material options (uPVC, aluminium) for durability and maintenance needs and review independent energy performance ratings. Check metrics such as U-factor and SHGC; consider double- or triple-glazing based on your climate. Validate quality through customer testimonials and case studies and confirm that products meet industry standards and come with robust warranties. Visit a window & door showroom to experience the quality of different products firsthand.

A FENSA certificate is a declaration issued to the homeowner by an installation company that confirms that the windows and doors they have replaced are energy-efficient, registered with the local council, and comply with building regulations. The certificate is a valuable and essential document when selling the property, verifying that the warranty is in place and serving as proof that the work is professional.

Every FENSA-registered installer, like us here at Glevum Windows, is continually reassessed by an independent inspection body to ensure consistent adherence to the Building Regulations and service standards.

Do it as soon as you can to gain the energy-efficiency and security benefits sooner. Every time the Energy Price Cap rises, material and business running costs also increase.

DIY can cut labour costs, but it requires precision—improper installation can compromise efficiency and longevity. Professional installation from a well-established installer such as Glevum Windows Ltd offers expert fitting and sealing, fewer errors, and installer guarantees, which can extend window life and performance. If you’re unsure about your skill level or the project’s complexity, professional installation is the safer choice.

It depends on your home and which way it faces. Triple glazing can push U-values down to around 0.8 W/m²K and is great for heat retention in north-facing rooms or very cold climates, but it typically costs 20–30% more. For the average UK home, A-rated double glazing usually delivers excellent comfort and savings at a better price point. Reserve triple glazing for new-build eco-homes, challenging orientations, or extreme conditions where the extra performance justifies the premium.

Aluminium typically has the longest lifespan and excels in harsh conditions. It’s highly durable and corrosion-resistant and can withstand severe weather—making it a strong choice for coastal or industrial areas. uPVC also resists rot, rust, and corrosion, but can warp or discolour under extreme temperatures. Overall, aluminium often outlives uPVC, though both require relatively low maintenance.

Pick windows that match your property’s style and how you use each room. Casement windows are usually the most affordable, very secure, seal well, and provide good ventilation. Keep in mind they open outward, which can block walkways. Sliding sash windows work well for period homes, especially Victorian ones, because they maintain the traditional look without protruding. Modern versions fix old problems like rattling and drafts, but they tend to cost more. Tilt-and-turn windows give you flexible ventilation—tilt them for gentle airflow or turn them inward for maximum air and easy cleaning. They are also very secure because of strong internal multi-point locks.

• Sliding Sash: Classic, versatile look with easy cleaning and strong ventilation in a space-saving design—great for many home styles.
• Casement: Modern, sleek appearance with efficient ventilation, clear views, and tight seals that support energy performance.
• Picture: Fixed panes that don’t open but deliver expansive natural light, uninterrupted views, and a striking focal point—ideal for boosting aesthetics and perceived space.

Choose aluminium. Its structural strength supports larger panes and enables sleek, slim frames that maximise natural light—ideal for modern, minimalist designs. uPVC offers a wide range of styles and finishes (including wood-like looks), making it easy to match traditional homes, but its frames are typically bulkier.

Standard double glazing is usually prohibited for listed properties because it alters the historic fabric. The go-to solution is secondary glazing: a discreet internal unit added behind the original single-glazed window. It typically avoids the need for planning permission, substantially improves thermal performance, eliminates draughts, and significantly reduces noise, all while preserving the building’s external appearance. For conservation areas, look for Conservation Area Approved Windows, such as the Residence R9 from Glevum Windows Ltd.

Yes. Beyond energy and cost savings, replacing your windows will also reduce noise. However, standard glass units prioritise energy efficiency over noise reduction. If noise control is a primary reason for replacement, you will need to consider options like acoustic laminated glass.

uPVC generally provides better noise reduction thanks to airtight seals and strong insulating properties. Aluminium can achieve comparable sound performance when paired with enhancements like acoustic glass, but uPVC tends to be quieter by default.

Powder‑coated aluminium is very durable, but high‑grade modern uPVC is now a highly competitive, equally fade‑resistant alternative. With quality manufacturing and routine care, both materials maintain their appearance for decades.

Choose a material that fits your budget, design preferences, and the level of maintenance you are willing to do. For most UK homes, uPVC is the best value because it is durable, easy to look after, and provides good insulation at a reasonable price. Aluminium is a great choice if you want slim frames and large windows, which work well for modern styles and bi-fold doors. New aluminium frames with thermal breaks are also very energy efficient. Real timber looks best on period properties but needs regular care. If you like the traditional look but want something easier to maintain, try wood-effect uPVC or composite options that look like timber but are much easier to maintain.

Replacement windows must comply with Building Regulations: Part L (U-value ≤ 1.4 W/m²K), Part F (adequate ventilation—often via trickle vents), Part B (upper-floor escape windows where required), and Part K (safety glazing near floors/doors). Use a FENSA- or CERTASS-registered installer so they can self-certify and issue the compliance certificate you’ll need when selling. As a rough guide for a typical 3-bed home (8–10 windows), standard uPVC casements often cost £4,000–£6,500; aluminium £6,500–£9,000; timber alternative or high-end sash can exceed £10,000. Quality installation is as important as the frames and glazing themselves.

U-value measures how well a window insulates—lower is better. SHGC (Solar Heat Gain Coefficient) shows how much solar heat the window lets in—choose a value that matches your need to admit or limit heat, depending on your climate. VLT (Visible Light Transmittance) indicates how much daylight passes through. BFRC labels bundle these metrics to help compare overall energy performance at a glance.

Keep it simple and consistent:

• Clean frames and glass with mild, non-abrasive detergents
• Lubricate hinges, locks, and other moving parts
• Inspect and replace worn seals/weatherstripping
• Check for drafts and leaks, and address them promptly
• Clear drainage channels to prevent water build-up. Regular inspections catch small issues early and help maintain energy efficiency.

Consider replacement if you notice:

• Persistent condensation between glass panes
• Increasing difficulty opening/closing even after adjustments
• Significant rises in energy bills or recurring drafts
• Faded, brittle, or visibly damaged frames. If basic maintenance and targeted repairs don’t restore performance, a replacement will better protect comfort, efficiency, and kerb appeal.

Add draught excluders and seal gaps around frames and sashes; apply low‑emissivity window films to reduce heat transfer and fading; and consider secondary glazing for extra insulation. These upgrades are affordable, improve comfort, and can meaningfully reduce energy bills without full replacement.

uPVC windows are more affordable up front. Their initial cost and installation expenses tend to be lower. This makes them a budget-friendly option for many homeowners.

Aluminium windows, on the other hand, may require a higher initial investment, but their durability and longer lifespan can offer better value over time.

Look for comfort and condition issues. Common indicators include:

• Drafts or condensation
• Difficulty opening or closing
• Visible damage, decay, or warped frames
• Rising energy bills. Also consider age—many windows last about 15–20 years. If you’re performing frequent maintenance or seeing rot/decay, replacement is likely due.

Typical replacement costs range from £300 to £1,000 per window, depending on the style, size, and installation complexity. Energy-efficient windows generally cost more upfront—about £500 to £1,500 per window—but can reduce utility bills and improve comfort over time. Budget for:

• Window type and materials (i.e. uPVC or aluminium)
• Professional installation vs. DIY (labour savings vs. risk)
• Possible extra repairs (frames, sills). Get multiple estimates to refine your budget.

uPVC usually has a lower upfront cost and is more eco-friendly to produce, while still being durable. Aluminium often costs more initially but offers long-term value due to its longevity and is fully recyclable without loss of quality. Your choice should balance immediate budget, long-term value, and sustainability priorities.