How to find a window installer you can trust

Simon Edward • 10 November 2023

In a sea of choices, how do you find a reliable window installer you can trust? Learn how to avoid cowboy companies and find one that genuinely cares.


In a sea of choices, how do you find a reliable window installer you can trust? Learn how to avoid cowboy companies and find one that genuinely cares.

You’re ready to make the next step in your home improvements. 


Is it a new door, new windows, new conservatory or all three? 


Big decisions, for sure. But there's a bigger one to come: which door or window firm will you choose to do the job? 

The internet and local directories helpfully list many companies – but before you part with your hard-earned money, you want peace of mind that you're making the best choice.


We've all heard the horror stories!


So, how do you avoid being a victim of scammers and, instead, find a window installer you can trust?


You want a good return for your investment, high quality, improved kerb appeal for your home, good energy efficiency, security and a design that is tailored to you. 


Ticking all these boxes is no small feat. But if you follow our tips, you should have no trouble finding a firm that goes above and beyond.


Research the company's history 


Take the time to research the company.


What is their history? 


How long have they been in business?


The company's history is a powerful tool for establishing credibility and reliability. Years of experience produce a culture of teamwork among the staff and pride in their work.


Picture of a window installer

A company that has successfully weathered the storm in times of recession shows resilience, stability and a willingness to progress with new technologies. 


And a related question: is it a family-run business?


This is often a sign of a committed and unified leadership, which has built the business to pass on to the next generation. This all adds up to a brand you can trust.


Check reviews and ratings online


Why do we check reviews?


Because reviews build credibility. They offer an outlet for real customers to provide helpful feedback on a service or product – and, in turn, greatly enhance customer trust.


Picture resembling a star rating

Don't just look at the star rating. Read the in-depth reviews to see what customers appreciated most.


Was it the professional, friendly service? The quality of the product? How they dealt with potential problems? A well-rounded review will cover all these topics and give you a good overall view of the company ethos.


Make sure they're FENSA-approved


FENSA is a government-authorised scheme that regulates the window and door supply industry in the UK. It is a certificate of quality proving regulatory compliance within the law.


Since 2002, it is actually illegal to install double glazing without adhering to building regulations. This includes replacement of windows, doors, roof windows and roof lights in England and Wales. (Just replacing glass in an existing frame is exempt.)


You can only get a FENSA certificate from a FENSA-approved installer. It's a guarantee your installation complies with building regulations, is registered with the local council and is backed by guarantee insurance.


The FENSA website can help you find an approved installer in your area.


Look for qualifications


What qualifications do the installers have?


Are the staff qualified to an appropriate NVQ level?


Those working as glaziers, installing glass into frames and maintaining glazing installations (usually windows and doors) need a minimum of an NVQ level 2 in glazing.


For more experienced glaziers, you can expect an NVQ level 3 – along with further training in dealing with various recurring issues. This includes working with glazing installations that have complex requirements, such as the identification and rectification of technical problems.


In addition, there are qualifications for those who install replacement glass, supporting frames and units. 

Similar NVQ qualifications are needed in the role of window (fenestration) surveying. 


Ask for a guarantee


What guarantees does the installer offer?


While a FENSA certificate proves quality of workmanship and legal requirements, you'll want to know that the installer itself is confident in its workmanship and materials. A guarantee is a surefire signal of this.


Do they offer a quality-assured framework, ensuring all products are of a consistently high standard? Do they offer a warranty? How long is it? Does it match the standard length for a home improvement guarantee of 10 years?


Customer service on first contact


What are your first impressions?


In any customer-based industry, first impressions go a long way. Being able to visit a showroom allows you to view the products up close, assess the quality and ease of use, and explore finishes, colours, materials and designs.


Discussing your personal needs with an experienced member of staff will help you make a choice that's specifically tailored to you and your taste. They should also help answer questions on practical aspects, such as energy efficiency and security.



Picture of a salesperson talking in a friendly manner to a customer

You want to feel relaxed and assured throughout this first meeting. If they can't answer your questions and hit you with a hard sell instead, we advise that you run for the hills.


Ways to find trusted suppliers


A good starting point is to ask family, friends and neighbours for recommendations. There's no better recommendation than a personal recommendation, after all.


Failing that, look online. Use search engines or online directories such as yell.com. Browse each company's website and social media accounts to see testimonials and examples of projects they've worked on in your area.


You can also check reviews on independent sites such as www.checkatrade.com for verified customer feedback.

When you enter into conversations, don't be afraid to ask questions. A reputable company will be happy to provide evidence of its experience and qualifications, official trade body membership and examples of previous work.


Its quote should be upfront about all costs involved. This includes things such as scaffolding (if needed), removal and disposal of old doors and windows, and repairing any plaster around the new windows.


Calder Windows is a family-run business that has provided window fitting services for over 30 years – with more than 100 years of combined expertise in our team.


Our reviews are a testament to our friendly, helpful and professional service. We pride ourselves on our great aftercare and provide a 10-year warranty on nearly all products.


View our range online or come and meet us at our showroom in Wakefield. Our friendly staff would be delighted to help you.


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