How to Compare Double Glazing Quotes in the UK
Comparing double glazing quotes is not about the biggest number at the bottom. It is about making sure every installer is pricing the same job, then reading the detail that the totals hide.
Key takeaways
- Standardise the specification before you ask for prices, or you are comparing different products.
- Check scope line by line: disposal, making good, scaffolding, certification and guarantee length.
- Three itemised quotes gives you a market price; one quote gives you a sales pitch.
- A quote 25% below the others is usually a smaller job, not a better deal.
Most homeowners compare double glazing quotes by looking at the total at the bottom of each page. That is the least useful number on the quote, because the total only means something once you know exactly what is inside it. This guide gives you a repeatable method that takes about twenty minutes and works for any installer.
Step 1: define the job once
Walk your property and write down every opening: the size, the style, whether it opens, and any special glass such as obscure or toughened. Decide the frame material and colour, and the glazing specification. Then send that exact list to every installer you contact.
This single step removes most of the confusion. When three installers price the same list, differences become visible and explainable. When each one prices what they think you want, the totals are meaningless.
Step 2: insist on itemised quotes
| Line to check | Why it matters |
|---|---|
| Every opening listed separately | Reveals a missing window that explains a low total |
| Frame profile and manufacturer named | A “uPVC window” can be three different products |
| Glass specification and energy rating | A-rated is the baseline; B-rated is cheaper and colder |
| Opening lights identified | Fixed lights cost less; a fully opening house costs more |
| Hardware and safety glass | Restrictors and toughened glass are often quietly omitted |
| Disposal of old frames and glass | Typically £10 to £25 per window if charged later |
| Making good inside and out | £300 to £800 across a house if it is not included |
| Scaffolding and access | £500 to £1,500, and who arranges it |
| FENSA or CERTASS registration | You need the certificate when you sell |
| Guarantee length and who backs it | Manufacturer cover and installer cover are different |
| VAT | Domestic quotes must show VAT-inclusive totals |
| Payment schedule | A large deposit up front is your risk, not theirs |
Step 3: compare scope before price
Put the three quotes side by side and tick off each line above. If one quote is missing disposal, making good and certification, add a realistic allowance for each before you compare. That quote is no longer the cheapest, and you have avoided discovering it after the fitters leave.
Step 4: weigh the things that are not on the page
- Who actually fits the windows: employed teams or subcontractors.
- How long the company has traded, and whether it has a physical local address.
- What recent customers say about aftercare, not just the sale.
- Whether the guarantee is insurance-backed, so it survives if the firm stops trading.
- How they handled the survey and the questions you asked.
Step 5: decide, then negotiate once
Pick the installers whose quote and conduct you trust, then ask your preferred one to match or improve on the best comparable price. Do this once, with the other quotes in front of you, rather than haggling repeatedly. Then get the agreed scope, price and date written into the contract before any deposit is paid.
The bottom line
Define the job, demand itemisation, compare scope before totals, and check the firm behind the price. That process beats any calculator, and it is the reason three quotes is the standard advice rather than a sales tactic.
Frequently asked questions
Three. Two gives you a choice, three gives you a market and shows which price is the outlier. More than four usually adds effort without adding information.
No. The cheapest quote is frequently a smaller scope. Compare what each price includes, then judge value rather than the headline figure.
The glass specification and the scope inclusions, especially disposal, making good, scaffolding and certification. Those four items account for most of the price gaps homeowners discover later.
Yes, if you supplied exact measurements and a full specification. A remote quote is only as good as the information you gave, so confirm nothing is provisional pending survey.
Compare quotes from trusted local installers
Answer a few quick questions about your project and we will match you with up to three vetted installers covering your area.
Related guides
Double Glazing Quote Checklist for Homeowners
Sixteen checks to run against any double glazing quote before you sign. If a box cannot be ticked in writing, treat it as missing.
5 min readRead guide Comparing QuotesWhat Should Be Included in a Double Glazing Quote?
A double glazing quote should be a specification, not a price on a business card. Here is everything that should appear in writing before you compare anything.
7 min readRead guide CostsHow Much Does Double Glazing Cost in the UK?
Realistic 2026 double glazing prices for single windows and whole houses, the four things that actually drive the number on a quote, and how to compare installers on a like-for-like basis.
8 min readRead guide