Questions to ask window installers

A survey visit is your best chance to judge an installer, not just their price. The right questions for window fitters tell you how a firm works, what’s really included, and whether you’ll be looked after if something goes wrong. Here are the ones worth asking every installer who quotes.

About the company

• How long have you been trading, and do you use your own fitters or subcontractors?
• Are you registered with FENSA or CERTASS, and will I get a certificate?
• Can you point me to genuine reviews or recent local jobs?

These establish whether you’re dealing with an established local firm or a sales operation that passes the work on.

About the specification

• What exact glass and frame profile are you quoting, and what’s the U‑value?
• How many of the windows open, and are trickle vents included?
• Does the price include making good, waste removal and any scaffolding?

The answers let you check that every quote describes the same job before you compare totals.

About the guarantee and protection

• How long is the guarantee, exactly what does it cover, and is it insurance‑backed?
• How is my deposit protected?
• What happens if a problem appears a year or two after fitting?

A confident, specific answer here is reassuring; a vague one is a reason to look closer.

About the process and timing

• When would the survey and installation happen, and how many days on site?
• Will the same team do the whole job?
• What’s the payment schedule, and is there a cooling‑off period?

Read the answers, not just the words

How an installer responds matters as much as what they say. Straight, unhurried answers and a willingness to put everything in writing are good signs. Evasiveness, pressure to sign, or reluctance to name the actual products are your cue to be cautious.

Write the answers down

By the third survey it’s surprisingly easy to muddle which installer promised what. Keep a simple note against each firm — the glass and frame they quoted, the guarantee length, whether it’s insurance‑backed, the deposit terms and your gut feel about them. When the written quotes arrive you can check each one against what was actually said on the day, and any gap between the promise and the paperwork becomes an easy question to raise before you commit.

Trust your impression of the visit

Price aside, the survey tells you what this firm is like to deal with. Were they punctual, tidy and happy to explain things? Did they measure carefully or glance around and reach for a calculator? You’ll be living with their work for decades, so a good working relationship counts — and it’s another thing you can only judge by inviting more than one installer round.

Ask the same questions of each installer and you’ll gather answers you can line up side by side — which is exactly what turns three visits into a fair comparison.