Top 10 Mistakes When Buying New Windows (UK Homeowner Guide)
Avoid costly errors when buying new windows.
Discover the top 10 mistakes UK homeowners make and how to choose the right windows for your home.
Buying new windows is a major investment—but many homeowners make avoidable mistakes that lead to poor performance, higher costs, and long-term frustration.
In this guide, we break down the top 10 mistakes when buying new windows in the UK, and how to avoid them.
1. Choosing the Cheapest Option
It’s tempting to go with the lowest quote—but cheaper windows often mean:
- Lower energy efficiency
- Shorter lifespan
- Lower-quality hardware
What to do instead:
Focus on long-term value, not just upfront cost. Better windows save money over time.
2. Ignoring Energy Efficiency Ratings
Not all windows perform the same.
Key things to check:
- U-values
- Window Energy Ratings (WER)
- Double vs triple glazing
Poor-performing windows can significantly increase your heating bills.
“From the day work started through to completion, they have been first class and they came through on all the promises made at the pre-contract stage discussions. We are delighted that we chose to appoint Marlin Windows to the contract and we would not hesitate in working with them again in the future.”
Rob Storton, Ilkley – Home Owner
3. Not Checking Compliance with Building Regulations
All replacement windows in the UK must comply with Building Regulations.
Common issues include:
- Incorrect glazing in critical areas
- Lack of proper ventilation
- Missing certification
Tip: Always ensure your installer provides certification after installation.
4. Overlooking Installation Quality
Even the best windows will fail if installed incorrectly.
Bad installation can lead to:
- Draughts
- Water leaks
- Poor insulation
Remember: A quality installer is just as important as the window itself.
5. Choosing the Wrong Frame Material
Different materials suit different needs:
- Aluminium: Slim, modern, long-lasting
- uPVC: Affordable, low maintenance
- Timber: Traditional look, higher upkeep
Mistake: Choosing based on price alone without considering durability and style.
6. Not Matching Windows to Your Property Style
Your windows should complement your home.
This is especially important in:
- Period properties
- Conservation areas
Choosing the wrong style can negatively impact your home’s appearance—and even planning approval.
Great service and great sliding doors.
From meeting Karl to discuss our requirements, to the doors being delivery the process was simple and smooth. Even measuring the size of the doors myself.
If you want high quality and competativly priced doors I would recommend Marlin windows.
John Roman – Queensbury
7. Overlooking Security Features
Windows are a key entry point for intruders.
Look for:
- Multi-point locking systems
- Internal glazing beads
- PAS 24 certification
Security should never be an afterthought.
8. Forgetting About Ventilation
Modern windows must allow for proper airflow.
Without it, you may experience:
- Condensation
- Mould growth
- Poor indoor air quality
Trickle vents are often required to meet regulations.
9. Not Reviewing the Warranty Properly
Not all guarantees are equal.
Before you buy, check:
- What’s covered (frames, glass, hardware)
- Length of warranty
- Whether installation is included
Final Thoughts
Avoiding these common mistakes will help you choose windows that:
- Improve energy efficiency
- Enhance your home’s appearance
- Add long-term value
Investing in the right windows—and the right installer—makes all the difference.
Latest projects
CONTEMPORARY WINDOWS
Contemporary Aluminium Glazing, Louper Weir, Lake District – New Build
CONTEMPORARY SLIDING DOORS
Ilkley Contemporary Sliding Patio Door Installation
BI FOLD DOORS
Bi-fold Doors Ben Rhydding – Ilkley
Frequently Asked Questions
If you require any support, please don’t hesitate to review our FAQ’s below or drop us a message on our contact form here
How much should I budget for new windows in the UK?
Costs vary depending on size, material, and glazing, but investing in quality products typically saves money long-term.
Do renewing windows and doors add value to a home?
Yes—especially in extensions where indoor-outdoor living is a priority.
Do I need permission to replace windows?
Most replacements fall under permitted development, but rules can vary—especially in conservation areas.
Come and explore…
Aluminium Bi-fold Doors, Sliding Doors, Contemporary Glazing, Aluminium Heritage Windows and Traditional Steel Replacement Doors
