Windows and doors is a trade with a long history of high-pressure selling, and homeowners are right to be cautious. The good news is that separating a solid installer from a poor one is not difficult if you know what to look at.
This guide gives you the questions, the paperwork checks and the warning signs, in the order you will meet them.
How to choose a window and door installer: step by step
- 1
Shortlist three firms
Mix a local independent with one or two larger companies so you can see the range of pricing and approach.
- 2
Check registration
Replacement windows are notifiable work. Confirm the installer is registered with a competent person scheme or will notify the local authority, and that they carry public liability insurance.
- 3
Ask who does the fitting
Find out whether the company employs its fitters or subcontracts. Subcontracting is not automatically bad, but it changes who is accountable when something needs adjusting later.
- 4
Get everything in writing
Profile system, glass specification, colour, hardware, whether disposal and making good are included, timescales, and payment stages.
- 5
Compare like with like
Put the three quotes on one sheet against the same criteria. The cheapest is almost always missing something.
- 6
Check the guarantee
Ask how long, what it covers, whether it is insurance-backed, and who honours it if the company stops trading.
- 7
Sanity-check the deposit and terms
A modest deposit against made-to-measure goods is normal. Full payment upfront is not. Confirm your cancellation rights in writing.
The questions worth asking
- Which profile system do you use, and can I see the specification?
- Who will physically be in my house, and are they employed or subcontracted?
- Is removal and disposal of the old windows included?
- How will the inside and outside be finished — trims, sealant, plaster?
- What happens if a sash needs adjusting in eighteen months?
- Is your guarantee insurance-backed, and by whom?
- How long between order and installation?
- Can you show me a recent job locally?
Red flags
| What you see | What it usually means |
|---|---|
| Price drops thousands during the visit | The opening price was never real |
| 'Today only' discount | Pressure tactic; a fair price is a fair price tomorrow |
| A visit that lasts two hours | Selling, not surveying |
| Full payment demanded upfront | Cash-flow risk sitting with you |
| No written specification | Nothing to hold them to |
| Reluctance to give an address of past work | Nothing they want you to see |
| Quote arrives with no company details or VAT position | Hard to pursue if it goes wrong |
Reading a quote properly
A good quote names the profile system, states the glass specification and energy rating, lists each opening with its configuration, and separates out any structural or making-good work. It gives a lead time, a payment schedule and a guarantee.
A poor quote is a single line and a number. You cannot compare it against anything, and you have no evidence of what you were promised if the wrong thing turns up.
Deposits and consumer rights
Made-to-measure windows are exempt from the usual change-of-mind cancellation rights once manufacturing starts, which is exactly why the cooling-off period matters. If the contract was signed in your home, you generally have a 14-day cancellation window, and the installer must tell you so in writing.
Paying a deposit by credit card can give you additional protection on purchases over £100. It is worth doing even if you clear the balance immediately.
Local independent vs national company
| Local independent | National company | |
|---|---|---|
| Price | Usually lower | Higher, with bigger discounts offered |
| Who fits | Often the owner | Employed or subcontracted teams |
| Aftercare speed | Usually faster | Process-driven, can be slower |
| Guarantee security | Depends on insurance backing | Usually backed |
| Product range | Narrower | Wider |
| Continuity if the firm closes | Risk | Lower risk |
What we do
For what it is worth, this is how we work across Central Scotland: one survey, one written price back with you within 48 hours, no discount theatre, and the person who quotes is the person who fits. If you would like a quote to compare against, call 07538 882579.
Common questions
Not at all — any decent installer expects it and will not be offended by being asked to compete.
Want a straight answer on your own windows or doors?
DM Installations fits and repairs windows and doors across Central Scotland — Cumbernauld, Glasgow, Falkirk, Stirling and the surrounding towns. Free survey, written quote, and an honest answer on whether you need a repair or a replacement.
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