Search for double glazing in almost any UK town and the first page belongs to Checkatrade, MyBuilder, Which? Trusted Traders and three national installers with television budgets. A local company with eleven vans is competing against directories that have spent twenty years accumulating authority.
That is the defining feature of glazing search, and almost no guide on the subject says so. This one starts there, because it decides where a local installer can realistically win and where the money is being wasted.
It also covers the two compliance layers specific to this trade, both of which sit on your highest traffic pages: the U-value figures that are now a matter of building regulations rather than marketing, and the savings claims the Competition and Markets Authority is enforcing against.
Watch: how AI picks a window company
A minute on what actually decides which installers get named when someone asks an assistant for a recommendation.
Who you are actually competing with
| Competitor type | What they have | Where they are weak |
|---|---|---|
| Directories, meaning Checkatrade and similar | Domain authority, review volume, national coverage | No local depth, no product specificity, generic pages |
| National installers | Budget, brand search, television support | Slow, templated at town level, poor at niche products |
| Manufacturer sites | Product authority and technical content | They do not install, so they cannot serve local intent |
| Other local installers | The same position as you | Usually a five page site and no content at all |
The conclusion follows from the table. You will not outrank Checkatrade for “double glazing” and should stop trying. You can beat all four for the specific product in the specific place, because a directory has nothing to say about aluminium bifolds in your town and a national installer will not write about it.
Where a local installer wins
- Product plus place. Aluminium windows in a named town rather than windows nationally. Lower volume, far higher intent, and the directories cannot serve it well.
- Specific products. Sash window replacement, conservation area glazing, slimline aluminium, triple glazing, composite doors. Narrow terms with real buyers behind them.
- Problem searches. Condensation between panes, draughty windows, failed units, misted glass. High volume, low competition, and they precede a replacement decision.
- Compliance questions. Whether building regulations apply, what a FENSA certificate is, what happens at sale. Nobody selling windows writes about this properly.
- Cost content. The single most searched thing in this trade and the thing installers are most reluctant to publish.
The pattern is consistent. The searches you can win are the ones a directory cannot answer without local knowledge or technical detail.
U-values are now a factual claim, not a marketing one
Part L of the Building Regulations sets the standard for replacement windows in England and Wales. As of 2026, the whole-window U-value for a replacement must be 1.2 W/m²K or lower. Installing above that is not compliant and can attract enforcement from local authority building control.
That has two consequences for a website. First, any U-value stated on a product page is a claim about regulatory compliance and needs to be accurate to the specific product and the whole window rather than the glass alone. Second, it is a content opportunity, because homeowners search for this and the pages that answer it are mostly written by manufacturers rather than installers.
FENSA, CERTASS and the certificate
Replacement windows and external doors in England and Wales fall under the competent person scheme regime. A registered installer can self certify compliance with Part L and Part Q, which avoids a building notice fee of more than £200 and the wait for a local authority inspection.
| Scheme | Position |
|---|---|
| FENSA | Fenestration Self-Assessment Scheme, established 2002. The larger of the two and the one conveyancers recognise. |
| CERTASS | Identical in legal effect. Less familiar to solicitors, which occasionally matters at sale. |
| The certificate | Must be issued within 10 working days of installation and must state the whole-window U-value. |
The commercial point is that this comes up at sale. A homeowner selling a property needs the certificate, and a buyer's conveyancer will ask. Explaining that clearly on your site answers a real anxiety and earns links from unexpected places.
Savings claims are your highest risk pages
Every glazing site carries numbers. Save up to X per cent on heating. Pays for itself in Y years. A-rated. Those are the claims the Competition and Markets Authority enforces against, and it has taken undertakings from major retailers over green claims.
| Claim as usually written | The problem | Safer version |
|---|---|---|
| Save up to 40 per cent on heating bills | “Up to” describes a best case most customers will not see | State the baseline, the property type and the source |
| Pays for itself in ten years | Depends on the existing windows, tariff and usage | Show the assumptions and say what changes the answer |
| Eco-friendly windows | Vague environmental claim with nothing behind it | Name the measurable property, meaning the U-value |
| A-rated windows | A rating band is not the same as the regulatory U-value | State both, and say which one building control cares about |
If you advertise finance, you are a credit broker
This is the gap in every glazing marketing guide we reviewed, and it is the one with the sharpest teeth. Almost every installer offers finance, and almost every installer advertises it on the site.
Consumer credit agreements for home improvement are regulated by the Financial Conduct Authority. An installer introducing a customer to a lender such as Novuna or Ideal4Finance is credit broking, which is a regulated activity. Doing it without permission is not a marketing problem.
| What you are doing | What it requires |
|---|---|
| Introducing customers to a lender | FCA credit broker permission. Limited permission is available where broking is ancillary to selling your own goods and services, which fits most installers. |
| Advertising the finance on your website | It is a financial promotion. It must be clear, fair and not misleading, like any other. |
| Promoting a genuine 0 per cent APR offer | Does not trigger the full representative example, but the clear, fair and not misleading standard still applies. |
| Quoting any other rate or a monthly payment | Triggers the representative example requirements. This is where most installer sites fall over. |
| Earning commission on the introduction | Must be disclosed. You must also be clear you are introducing to a lender rather than lending yourself. |
The practical consequence for a website is specific. A finance page carrying a monthly payment figure without the representative example is a non-compliant financial promotion. A landing page built by a marketing agency that has never read CONC will almost certainly be one.
Our financial services marketing page covers the promotion rules in more depth, including why FCA interventions on promotions nearly doubled in a single year.
Site architecture
The failure mode here is well known and still ubiquitous: fifty location pages with the town name swapped, competing with each other and ranking for none of them.
- Product pages. One per material and style, with technical detail, U-values, security ratings and honest pricing ranges.
- Location pages. Only for places you genuinely serve, each with real local content: recent installations, conservation constraints, parking and access, the local authority.
- Product plus location. The combinations you actually want, built deliberately rather than generated. Ten good ones beat two hundred thin ones.
- Problem pages. Condensation, draughts, failed units, security. These capture the search that precedes the purchase.
- Compliance pages. Building regulations, FENSA certificates, what happens at sale. Almost nobody has these.
A location page that could apply to any town is a location page Google has no reason to rank. If you cannot write two paragraphs that are true only of that place, do not build the page.
Local search, with the actual weights
Whitespark's Local Search Ranking Factors for 2026, published November 2025 from 47 practitioners scoring 187 factors, puts Google Business Profile signals at 32 per cent of local ranking weight, review signals at 20 per cent and on-page at 19 per cent. AI search visibility appeared as a formal category for the first time.
- Primary category chosen deliberately. Window installation service, glazier and door supplier are different categories with different results.
- Service areas set accurately rather than optimistically. A radius covering half of England helps nothing.
- Photographs of real installations, added regularly, because profile activity is a freshness signal.
- Name, address and phone identical everywhere, including trade directories nobody has checked in years.
- Questions and answers seeded and monitored, since anyone can answer them.
Reviews, and the Checkatrade question
Installers routinely pour review effort into Checkatrade and leave Google thin. That is backwards for search. Review signals are about a fifth of local ranking weight, and it is Google reviews that carry it.
The survey found 41 per cent of consumers now always read reviews, up from 29 per cent, and 68 per cent will only use a business rated four stars or higher. Recency matters more than total: a company with 200 reviews and nothing in six months is weaker than one with 60 and a steady monthly flow.
Keep the directory profiles, because buyers check them. Just stop treating them as the primary place to collect.
Technical
Core Web Vitals changed in March 2024, when Interaction to Next Paint replaced First Input Delay as the responsiveness metric.
| Metric | What it measures | Threshold |
|---|---|---|
| LCP | When the main content appears | Under 2.5 seconds |
| INP | Responsiveness across every interaction | Under 200 milliseconds |
| CLS | How much the layout jumps | Under 0.1 |
A metric passes only when at least 75 per cent of real page views hit the good threshold, and INP is the most commonly failed, at around 43 per cent of sites. Glazing sites fail it for a predictable reason: quote calculators, gallery sliders, finance widgets and chat all loaded on every page rather than only where they are used.
Image weight is the other perennial. This trade photographs everything and uploads at camera resolution. Sized and compressed images fix more glazing sites than any other single change.
Structured data
| Type | Use it for |
|---|---|
| HomeAndConstructionBusiness | The company itself, a LocalBusiness subtype that describes the trade accurately. |
| Service | Each installation service, with area served. |
| Product | Window and door ranges where you publish specifications. |
| FAQPage | Only where the questions genuinely appear on the page. |
Certifications belong in the markup too. FENSA or CERTASS registration, TrustMark, and any manufacturer approvals are the checkable facts that separate you from a directory listing, and they are exactly what an AI system looks for when deciding whether a business is real.
E-E-A-T for a trade
Replacing windows is a five figure decision affecting the fabric of somebody's home, so this behaves like a Your Money or Your Life category even though it is not clinical. Pages are judged on signals that sit outside the page.
| Signal | What it means for an installer |
|---|---|
| Experience | Real installations with photographs, locations, product used and what the constraints were. |
| Expertise | Technical content written by someone who fits windows, including U-values and regulations. |
| Authoritativeness | FENSA or CERTASS registration numbers, TrustMark, manufacturer approvals, Companies House. |
| Trust | Published price ranges, named people, a real address, and honest treatment of what can go wrong. |
Published pricing is the one most installers resist and the one that separates them fastest. Buyers comparing five companies discount the ones that hide it, and a range with the variables explained is more persuasive than a form.
AI search, and being honest about it
Assistants increasingly answer the questions that precede a glazing purchase. What causes condensation between panes, whether building regulations apply, what a reasonable price is.
The best evidenced data on AI citation comes from health, where more than 82 per cent of queries trigger an AI Overview and around 80 per cent of cited sources also rank organically. Home improvement is less studied, so we would not quote a trigger rate for glazing. The mechanism is the same though: conventional ranking is the route in, and models cite entities they can resolve and corroborate.
Two practical points. Check that GPTBot, ClaudeBot and PerplexityBot are not blocked by a security plugin or CDN rule, which happens constantly and without anyone deciding it. And state the facts a model can verify: registration numbers, area served, products, certifications, prices.
Measuring it is the harder half, because rank trackers do not capture it. We built Axiom GEO for that, monitoring brand presence and citation across ChatGPT, Perplexity, Gemini and Claude, including the case that matters most: when the assistant answers a buyer's question and names a competitor.
The mechanics are in our generative engine optimisation guide and entity maps guide.
What to measure
| Measure | Why |
|---|---|
| Enquiries by landing page | Which pages earn surveys, rather than which rank. |
| Survey to sale conversion | If this is weak the problem is downstream of marketing. |
| Local pack calls and direction requests | Not visible in Search Console, and often the majority of contact. |
| Cost per survey against cost per sale | The gap tells you whether the traffic is qualified. |
| Core Web Vitals field data | Real user data rather than a lab score. |
| AI citation share | Whether assistants name you for the questions buyers ask first. |
What we see glazing companies get wrong
- Chasing head terms owned by directories and national brands, at budgets that cannot win them.
- Fifty templated location pages with the town swapped, competing with each other.
- Savings claims with no stated basis, on the highest traffic pages.
- U-values quoted for the glass rather than the whole window, when the whole window is the figure building control cares about.
- Review effort concentrated on Checkatrade while the Google profile stays thin.
- Quote calculators, sliders and chat loaded site wide, then a puzzled look at the INP score.
- Photographs uploaded at camera resolution, on a site full of photographs.
- No pricing anywhere, in a market where the first thing every buyer searches is cost.
- FENSA registration mentioned in the footer and nowhere in the markup.
Claims in this space, rated
| Claim | Verdict |
|---|---|
| You can rank for “double glazing” locally | Not against directories and national advertisers. Product plus place is winnable. |
| Replacement windows must be 1.2 W/m²K or lower | Correct for 2026 under Part L, whole window rather than glass. |
| FENSA is legally required | Untrue. A competent person scheme or building control notification is required. FENSA is one route. |
| CERTASS is worth less than FENSA | Identical in legal effect. FENSA is better recognised by conveyancers. |
| More location pages means more traffic | The opposite, when they are templated. They compete with each other. |
| GBP is 32 per cent of local ranking weight | Whitespark 2026, 47 contributors, 187 factors. Usable. |
How we work with installers
Keyword strategy built around what a local installer can actually win rather than what a national brand owns. Architecture that gives products, places and problems their own pages instead of a template. Compliance review of the U-value and savings claims already on your site. Technical work aimed at the metric that fails. Review generation pointed at Google rather than only the directories. And AI visibility measured with Axiom GEO rather than assumed.
Our home improvement marketing guide covers the wider channel mix, including the bought lead problem and the cooling-off rules that shape the sale.
Tell us what is not working and we will give you an honest answer, including when the answer is that your search is fine and the problem is elsewhere.
Sources
- Building Regulations Part L, whole-window U-value requirement for replacement windows in England and Wales.
- FENSA, the Fenestration Self-Assessment Scheme, and CERTASS, competent person schemes for replacement windows and external doors.
- Competition and Markets Authority, green claims guidance and enforcement action.
- Whitespark. Local Search Ranking Factors 2026, published November 2025.
- Google. Core Web Vitals thresholds, and the March 2024 replacement of First Input Delay with Interaction to Next Paint.
- Schema.org. HomeAndConstructionBusiness, Service and Product type definitions.
- Search industry analyses of AI Overview citation patterns, 2026.
- Axiom GEO, generative search visibility monitoring across ChatGPT, Perplexity, Gemini and Claude.
Regulations, thresholds and ranking factors change. This guide was last reviewed in July 2026. If something here is out of date, tell us and we will correct it and note the change.
