How to Choose a Window and Door Fitter: 7 Checks Before You Hire
Window and door fitters supply and install windows, doors, conservatories and roofline products. Replacement windows and doors must meet Building Regulations, which is where FENSA or CERTASS certification comes in. These seven checks take less than half an hour and filter out most of the operators you'd regret hiring.
1. Read reviews across more than one platform
Search the company name plus “reviews” and look at several sources, not just the one the company links to. Hammerscore company pages for window and door fitters combine ratings from multiple platforms into one score with links to the originals.
Read the negative reviews first. What matters is whether the same complaint repeats and how the business responds — a calm, specific reply is a good sign; blaming every customer is not.
2. Verify the credentials that matter
FENSA or CERTASS-registered installers can self-certify that replacement windows and doors meet Building Regulations and issue the certificate you need when selling your home. Check the company on the scheme's own register.
3. Confirm insurance
Ask to see a current public liability insurance certificate. This covers damage to your property and injury to others. For larger jobs, also ask how your deposit is protected and whether any guarantee is insurance-backed.
4. Get three written quotes
Describe the same job to three companies and compare written quotes line by line. A proper quote lists the work, materials, start date, duration, payment stages and VAT. The form on any Hammerscore company page can request quotes from similar companies nearby.
5. Check the paperwork trail
The name on the quote, invoice and van should match the business you checked. Limited companies can be verified free on Companies House; sole traders should still give you a trading address and landline.
Red flags specific to this trade
Any one of these deserves a pause; two together mean look elsewhere.
- today-only discount pressure — a classic in this trade
- no mention of FENSA or CERTASS certification
- a deposit larger than about 25% before manufacture
After the job
Pay by a method with a record, keep the paperwork, and leave an honest review — good or bad. It is the most useful thing you can do for the next person searching this company's name.
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