How we score quotes.
Every quote is checked against the same 30+ factors in five categories. This page lists every factor, every point and every threshold, in full.
What the score means
Each category is scored out of its points and turned into a percentage. The overall score is the average of the five, with every category carrying equal weight. Each range of scores has a plain verdict.
- 90–100A strong quote
- 75–89A good quote
- 60–74Could be worth it
- 40–59Gaps to ask about
- 0–39Not a strong quote
01 · Product quality
Worth 100 points. The physical specification of the windows or doors themselves — the most lasting impact on comfort, energy bills, and security.
| Factor | Points |
|---|---|
| U-value (thermal performance)≤1.4 = 18 pts baseline; each 0.1 below adds 1 pt up to 25; each 0.1 above deducts 3 pts (minimum 3). A U-value of 1.4 W/m²K meets current Scottish Building Standards minimum. | 25 |
| Frame sightline widthNarrower sightlines mean more glass and a cleaner look. <85 mm = 15 pts; 85–89 mm = 12 pts; 90–99 mm = 8 pts; ≥100 mm = 5 pts. | 15 |
| Frame materialEngineered timber composite = 15 pts; PVC-U or aluminium = 12 pts; Timber = 10 pts. | 15 |
| Glazing specificationDouble argon, Low-E, warm-edge spacer = 15 pts; double argon Low-E = 12 pts; double argon = 10 pts; triple glazed = 12 pts; double basic = 5 pts. | 15 |
| Hardware qualityNamed hardware with specification = 10 pts; named, no detail = 7 pts; generic reference = 3 pts. | 10 |
| Security accreditationPAS 24 + Secured by Design = 10 pts; PAS 24 alone = 8 pts; other named standard = 5 pts; claim but no cert = 2 pts. | 10 |
| Energy rating (WER)A-rated = 10 pts; B = 7 pts; C = 5 pts; D or below = 2 pts. | 10 |
02 · Guarantees & aftercare
Worth 100 points. A guarantee is only as good as the company standing behind it. We look at length, coverage, and the company's ability to honour it long-term.
| Factor | Points |
|---|---|
| Product guarantee (years)≥20 years = 20 pts; ≥15 = 18 pts; ≥10 = 15 pts; 5–9 = 8 pts; <5 = 3 pts. | 20 |
| Installation guarantee (years)≥10 years = 15 pts; 5–9 = 10 pts; 2–4 = 5 pts; <2 = 2 pts. | 15 |
| Guarantee coverageParts, labour, and workmanship = 20 pts; parts and labour = 15 pts; parts only = 5 pts. | 20 |
| Guarantee reliabilityA composite score built from: years trading (0–10 pts), ownership stability (0–8 pts), and honour history (0–7 pts). Assesses how likely the company is to still exist when you need them. | 25 |
| Emergency callout24/7, 365 days = 10 pts; business hours only = 5 pts; available at extra cost = 3 pts; not offered = 0. | 10 |
| Guarantee transferabilityFully transferable on house sale = 10 pts; transferable with conditions = 5 pts; not transferable = 0. | 10 |
03 · Installation quality
Worth 100 points. Even the best windows underperform if poorly fitted. We assess who does the work, how they are trained, and what the process involves.
| Factor | Points |
|---|---|
| Fitter employment modelOwn employed fitters = 20 pts; mix of employed and subcontracted = 10 pts; subcontracted only = 4 pts. Employed fitters are accountable directly to the company. | 20 |
| Fitter trainingApprenticeship programme with named qualifications = 15 pts; named qualifications only = 10 pts. | 15 |
| How it’s fittedFitted from inside, behind the check = 20 pts; from inside = 14 pts; from outside with the gaps sealed = 6 pts; gaps filled with foam = 3 pts; from outside with foam in the gaps = 0. Fitted from outside, the frame never quite fits the opening and the gap is usually filled with foam, which loses much of the windows’ insulation, so in that case the U-value also counts only half. | 20 |
| Making good / finishingIncluded with detail = 15 pts; included but no detail = 10 pts; extra cost = 3 pts. | 15 |
| Building regs certificateScottish building control completion certificate included in price = 15 pts; handled but no detail = 10 pts; extra cost = 3 pts. This certificate is legally required in Scotland and protects you on resale. | 15 |
| Manufacturing locationScotland = 15 pts; UK = 10 pts; Europe = 5 pts; other or unknown = 0. | 15 |
04 · Company trust
Worth 100 points. Third-party signals that indicate a company's legitimacy, longevity, and commitment to quality.
| Factor | Points |
|---|---|
| Trustpilot score≥4.8 = 25 pts; 4.5–4.7 = 20 pts; 4.0–4.4 = 15 pts; 3.5–3.9 = 8 pts; below 3.5 = 3 pts. | 25 |
| Trustpilot review volume≥5,000 reviews = 15 pts; 1,000–4,999 = 12 pts; 500–999 = 9 pts; 100–499 = 6 pts; <100 = 3 pts. Volume validates that a score is statistically meaningful. | 15 |
| Years established≥50 years = 20 pts; 25–49 = 15 pts; 10–24 = 10 pts; 5–9 = 5 pts; <5 = 2 pts. | 20 |
| Ownership typeScottish family-owned = 15 pts; private single ownership = 12 pts; UK group = 8 pts; overseas parent company = 5 pts. | 15 |
| Industry certificationsBSI, BBA, or ISO accreditations — multiple = 15 pts; single = 8 pts. We do not score FENSA or Certass here as they are legal minimum requirements in England, not Scotland, and do not represent additional quality. | 15 |
| Scottish presenceHQ and manufacturing in Scotland = 10 pts; office only = 6 pts; operates in Scotland but based elsewhere = 3 pts. | 10 |
05 · Value for money
Worth 100 points. Price is not scored in isolation. A lower price on a weaker spec is not good value. A higher price on a comprehensively specified product may be fully justified.
| Factor | Points |
|---|---|
| Price vs market benchmarkBenchmarks are derived from regional Scottish market data and adjusted by product quality score. A quote scoring strongly on quality can justify above-average pricing. Significantly below market with good spec = 18 pts; at market with strong spec = 25 pts; above market without justification = 5 pts. | 25 |
| What's includedSeven items checked: survey, product supply, installation, building regs, making good, finishing/cleaning, and VAT. All 7 = 25 pts; 6 = 20 pts; 5 = 15 pts; 4 = 10 pts; fewer = 5 pts. | 25 |
| Payment termsSmall deposit (<25%) or none = 15 pts; 25–50% deposit = 8 pts; >50% deposit = 3 pts; full payment upfront = 0. Large upfront payments increase consumer risk. | 15 |
| Finance optionsInterest-free finance offered = 10 pts; finance with interest = 7 pts; finance available (no detail) = 4 pts; none = 0. | 10 |
| Specification clarityEvery product fully specified = 15 pts; most products specified = 10 pts; basic descriptions only = 5 pts; no product descriptions = 0. | 15 |
| Exclusions clearly statedNothing excluded (everything in price) = 10 pts; exclusions clearly listed = 7 pts; buried in small print = 2 pts; likely excluded but not mentioned = 0. | 10 |
Where the price benchmarks come from
Benchmarks come from Scottish market data for typical window and door installations, split by product type (casement, sash, bifold, composite door and so on) and adjusted for quantity.
They are spec-aware. A quote scoring 75% or more on product quality is compared with a higher price band, because better-specified products cost more to make. That way, quality suppliers aren’t penalised for charging for quality.
When something isn’t stated
If a quote doesn’t mention a factor, it scores zero for that factor. A company confident in its product will state the specification.
Your results always list what wasn’t stated, as questions to ask before you sign anything, not red flags to panic about.
Sources
- Scottish Building Standards, Technical Handbook (Domestic), Section 6: Energy
- BS EN ISO 10077 (thermal performance of windows) and PAS 24 (enhanced security)
- BFRC (British Fenestration Rating Council) window energy ratings
- BSI, BBA and ISO 9001 accreditation frameworks
- Scottish market pricing research: an anonymous survey of quotations, 2024–2025
- Consumer Rights Act 2015 guidance on guarantee and warranty obligations