Frequently Asked Questions - Buying Windows and Doors
What are the best windows for UK homes?
Should I replace all windows at once?
When is the best time to replace windows?
Spring and autumn are ideal due to mild weather and good working conditions. Scheduling during off-peak periods can sometimes lower costs or improve availability. Weigh local climate, fitting availability, and your own flexibility to find the most convenient and cost-effective window.
Should I DIY or hire a professional installer?
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.
Is triple glazing worth it over high-quality double glazing?
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.
Which windows last longer and handle harsh climates better?
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.
Which window style should I pick - casement, sliding sash, or tilt-and-turn?
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.
I want slim frames and large glass panes—what should I choose?
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.
I live in a listed building or conservation area - what are my options?
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.
Which material is better for soundproofing?
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.
Are uPVC windows better than aluminium?
Is uPVC as fade‑resistant as aluminium?
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.
How do I choose between uPVC, aluminium, and timber (or timber-look) frames?
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.
What regulations and certificates do I need - and what might it cost?
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.
What do U-value, SHGC, and VLT actually mean on window labels?
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.
What routine maintenance should I do to extend their life?
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.
How do I know it’s time to replace instead of repair?
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.
What are cost-effective upgrades if I’m not ready to replace my windows?
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.
Are uPVC windows cheaper than aluminium?
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.
What are the key signs I need new windows?
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.
How much do new windows cost in the UK?
What windows add the most value to a house?
What are the value propositions of sliding sash, casement, and picture windows?
- 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.
How much should I budget for window replacement?
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.
How do cost and environmental impact compare?
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.
“Friendly, helpful staff from sales person to fitter, excellent service all round.”
J Holyhead (Gloucestershire)
March 2026
“Very helpful and reassuring. My window and door were fitted by 2 very nice men and its prefect, we are so pleased, thank you so much.”
K Smith (Gloucestershire)
February 2026
“Very professional service from the quote to the fitting. Very pleased.”
J Ochiltree (Gloucestershire)
January 2026
“We have used Glevum many times over the last 25 years and have never been disappointed with the quality of workmanship, timely service and friendly approachable people.”
M Tattersall (Gloucestershire)
January 2026
"Excellent service and workmanship. Highly recommend."
M Tomlin (Gloucestershire)
November 2025
"Glevum were very professional throughout the purchase and installation and I am happy with the finished result. Installation team were courteous, neat and tidy throughout the process."
R Elliott (Gloucestershire)
November 2025