Hiring window fitters
Updated on

- Arm yourself with some basic knowledge first
- Check that they are registered
- Choose someone with relevant experience
- Find out how the tradesperson will be sourcing their materials
- Make sure they understand planning permission and Building Regulations
- Get a detailed quote from each tradesperson you’re considering
- Never pay in full upfront!
- Consider using a smaller firm
- Ask who will actually be doing the work
Let’s look at each of these in a bit more depth.
Arm yourself with some basic knowledge first
Before you get any windows specialists round to quote on your job, it’s a good idea to arm yourself with some basic knowledge of the subject. That way, you’ll be much more able to tell the difference between the products that are mentioned, and work out whether the quotes you’re given are reasonable.
The Double Glazing & Conservatory Ombudsman Scheme website is a good place to start learning about the different types of UPVC windows that are on offer. You can also find out about the difference between timber, UPVC and composite doors.
Check that they are registered
There are several Competent Person Schemes that cover the windows trade in the UK. FENSA and CERTASS are probably the two best-known schemes. The others that cover windows and doors are the Assure scheme and Stroma Certification.
It’s a good idea to choose a tradesperson who is registered with one of these schemes. They work with thousands of window specialists, aiming to raise standards within the profession and offering homeowners extra legal protection if anything goes wrong.
MyBuilder member Infinity Doors Ltd provide composite, aluminium, PVC and engineered timber windows and doors. Director Debbie Simmons explains the difference between FENSA and CERTASS - and highlights why choosing a tradesperson who is part of a Competent Person Scheme is so important:
Being registered with CERTASS, a tradesperson pays them per job, rather than paying a fixed rate fee as you would with FENSA. That’s why a lot of smaller companies would use CERTASS. And it still offers homeowners the same level of protection. They come out and look at our work in progress - to make sure we’re keeping up to standard.
If you’re CERTASS-or FENSA-registered, you also have to register with the Independent Warranty Association (IWA). They cover the homeowner - so if my company was to go bust, and one of my customers needed their window repaired, they would have an insurance-backed guarantee to ensure that happened.
Finally, we have to log all the jobs we do with CERTASS - and then they give a certificate directly to the homeowner. After that, CERTASS can contact the customer directly, and go and check our work at any point. And they really will make people go back and fix the work, if they’re not happy with what a tradesperson has done in any way.
Debbie Simmons from Infinity Doors Ltd
Choose someone with relevant experience
It’s important you choose a windows specialist who has experience of the sort of work you want done. For example, a tradesperson might be familiar with installing new double glazing, but that doesn’t necessarily mean that they understand how to repair an original sash window.
Once you’ve found someone with relevant experience, ask to view some of their recent work. Debbie emphasises:
I always suggest to local customers that they visit a nearby property that we’ve worked on - even if it’s just doing a drive-by.
If someone is paying a lot of money for something - for example we had an enquiry from a customer who wanted a huge aluminium sliding door set installed, which will cost around £5,000 - then they should definitely go and see something else we’ve done, of the same quality.
Debbie Simmons from Infinity Doors Ltd
Debbie suggests customers also ask to see samples of materials, so they can examine the quality of what they’re being offered:
There are just so many different sorts of windows that customers can buy - from very cheap to very expensive. And they should check what grade of glass they’re getting, as well, because the different grades have different thermal properties. You should really just go for A Grade glass or above, unless it’s going in a shed or garage or something like that.
Debbie Simmons from Infinity Doors Ltd
Find out how the tradesperson will be sourcing their materials
A windows specialist will usually have an established relationship with their materials supplier, says Debbie:
We’ve been to the factory - we’ve seen where it’s made, all in the UK - we’ve felt it, we’ve fitted it. And if there are any issues, we know we can ring someone up and usually get something couriered out that same day.
Debbie Simmons from Infinity Doors Ltd
Many homeowners hope to save money by sourcing materials themselves - often online - and then giving them to the tradespeople to fit. However, tradespeople are often cautious about using materials provided by the customer, so it’s important you ask whether there will be any issues with this in advance:
If the materials haven’t been sourced by us, we can’t offer any guarantee on them. Whereas if we’ve provided them, you’ll get a ten or 25 year guarantee on them.
If you buy something cheap online, you can never be 100% sure what you’re going to get. We had a customer who bought a cheap conservatory online - and it turned out to be lots of the bits that hadn’t been cut to size. Not only was it pretty flimsy, but we had to make a lot of extra cuts - which we obviously had to charge for. Buying materials cheaply online can prove to be a false economy!
Debbie Simmons from Infinity Doors Ltd
Make sure they understand planning permission and Building Regulations
Building Regulations may apply to certain window and door installations. And if they constitute major changes to your property, they may need planning permission.
You should do some initial research on this yourself before you hire a tradesperson. For example, it’s worth finding out whether your property is in a Conservation Area, and speaking to your local council to make sure the work you want to have done is likely to be approved.
However, a knowledgeable windows specialist should also have a good understanding of the planning and Building Regulations issues that commonly affect window installation. If you don’t feel confident about navigating the process yourself, many companies will be happy to advise on how to proceed, and may even be able to complete and submit the paperwork on your behalf.
Get a detailed quote from each tradesperson you’re considering
Contact at least three windows specialists, and get a quote in writing from each one.
You’ll need to be able to compare like with like - so make sure these quotes include any and all possible expenses, like labour, materials, the cost of hiring any scaffolding, the disposal of waste and so on.
Never pay in full upfront!
It’s not unusual to be asked for an instalment upfront, especially for larger jobs. Anthony Etheridge of A & E Glazing has been a member of MyBuilder since 2009, and has a strong customer feedback score.
In terms of payment, I work on the basis of a 25% deposit and the rest on completion”, he explains. “That’s just an indication of commitment on both sides. Generally speaking, the 25% doesn’t even cover the cost of materials; it’s just a demonstration of commitment from the customer.
Anthony Etheridge of A & E Glazing
Never pay the remaining balance until the job is complete and you’ve fully inspected the work.
Consider using a smaller firm
There are certain big double glazing companies that are virtually household names, in part due to the large sums they are able to spend on advertising, and their proactive, ‘door to door’ sales style.
However, you don’t need to choose one of the big, famous firms. In fact, in some cases you might end up paying more if you do, as their reputations mean they tend to charge more for their services.
Anthony explains why choosing a smaller local firm could be the right thing to do:
We’re a small independent firm, so we’re local and can offer good rates. We don’t use sales representatives - I go out and give them the price myself. The big companies - they tend to use all the old sales tactics - ‘buy it now’, ‘sign up today’, etc. I hear it all from customers; they can sit there for two hours sometimes, and a lot of sales are commission-based. I don’t work on commission.
Anthony Etheridge of A & E Glazing
Ask who will actually be doing the work
When each tradesperson comes to quote on your project, make sure you ask who will actually be doing the work. You need to find out which aspects of the job will be carried out by the tradesperson themselves, and which elements will be undertaken by other members of their team, or sub-contractors.
Many tradespeople subcontract out certain tasks - this is not necessarily a problem. But it’s important you find out the extent to which work will be outsourced - and crucially, who will take responsibility if there are any issues or problems.
Related questions on Ask a tradesperson
See what others are asking our expert tradespeople. Browse all questions
Windows & Door fitting
Bifold door leak
Anonymous user 05/06/2026 - 8.00 AM
Hi wanted some advice please I have some origin bi fold doors (3yrs old) Which have been supplied and installed by a company. In dec we noticed water pooling on tile on the left and damaged skirting. We’ve ripped off skirting board recently due to heavy rain and some plasterboard which was damp and inside when you put water in track it drains through holes of cill but still leaking in the corner inside too.This door is used for opening for access to garden Haven’t noticed anything on the opposite end of the bifold (that we can see) I’ve asked glazer and he put a bit of silicone at end of track but hasn’t made any difference Clearly it’s rain water hitting door and then leaks into track and trickles out onto brickwork inside .From what I can see there is foam there on inside and siliconed well outside. Please can someone help.. fed Up of being fobbed off as there’s been few issues with random windows around house. Is there a fix without removing the door?thanks
4 answers
Windows & Door fitting
Lintels
Anonymous user 05/06/2026 - 7.59 AM
If windows are replaced/to be replaced- If lintels are required, would the window fitter do this or would I need to source another trades person for this? We need new windows for our home and likely need lintels but before I ring around/shop for quotes - wanted to check with so I was prepared. Am aware there will be additional cost for lintels if required on top of the windows and installation
2 answers
Windows & Door fitting
Mrs
Anonymous user 05/06/2026 - 7.59 AM
50% deposit 25% deluvery materials 25% on completion of installation of bespoke porch doors..no breakdown of costs.. should this be requested?
3 answers
Need expert advice?
Ask a questionDiscuss your job with tradespeople so they can accurately estimate the cost.