How to Get More Double Glazing Customers and Window Leads

How UK window and door installers win customers: FENSA and Certass, guarantees, makers' schemes, showrooms, reviews and paid leads, with a first-call script.

Hugo BibbyPublished 2 November 202621 min read

Window and door installers get more customers from two kinds of route. The ones that cost fees and time rather than money per enquiry are your competent person scheme's homeowner search (FENSA or Certass), the manufacturers whose products you fit, a showroom, Google reviews and the streets you've already fitted on. The ones you pay for per click or per enquiry are your own ads, marketplaces such as Checkatrade and Bark, and bought leads.

Most of them come down to trust before the survey. Can the homeowner check you're registered? Will your guarantee survive if you stop trading? And will your price still stand if they don't sign on the night? Below: what each route costs and needs, a way to compare them on cost per order, and a script for the first call.

How do you generate window leads?

Here are the routes open to a window and door firm, with what each one costs as its own website published it on 2 November 2026.

Sources for the table are linked in each section below.

Are there free window leads?

Not quite. The nearest things are listings from organisations you already pay, or would pay anyway, and work you can do with your own customers. Each costs fees, hours or both, so count them when you compare routes.

1. Join a competent person scheme, and use its homeowner search

gov.uk lists replacing windows and doors among the projects that may need building regulations approval. There are two ways to deal with it. The job can go through a building control body. Or the homeowner can use an installer registered with a competent person scheme, who self-certifies that the work complies, tells the local authority where needed and gives the homeowner a certificate within eight weeks of completion. That certificate shows up in solicitors' searches when the house is sold. External doors less than half glazed are on gov.uk's exempt list.

gov.uk's current list of schemes, updated on 17 September 2026, names six for replacement windows, doors, roof windows and rooflights in existing homes: ASSURE, Blue Flame Certification, CERTASS, Certsure, FENSA and NAPIT. Two of them, FENSA and Certass, also put their members in front of homeowners.

FENSA calls itself a government-authorised scheme that monitors building regulation compliance for replacement windows and doors, and says its mission covers England and Wales (about FENSA). Homeowners search its installers by postcode, company name or FENSA ID, then send a quote request with the products, timeline and budget they have in mind. FENSA's page for installers describes these as "homeowner leads direct from the FENSA website straight to your inbox". The catch is on the homeowner's side of the form: every listed installer can quote, and the homeowner selects as many as they like.

FENSA's 2026 price list puts joining at £279.88 and registration at £178.85 a year. On top of that, each onsite assessment is £145.25 (one a year for up to 25 jobs notified, two for 26 to 200) and each job you notify is £2.05. All of these are before VAT, and FENSA needs enough of your team to hold its Minimum Technical Competency (MTC) card.

Certass says it has been a government-authorised certification body since 2006 (Certass). Its competent person scheme covers replacement windows, doors, rooflights and roof windows in dwellings, at £26.95 a month plus £1.85 for each job registered, both plus VAT, with membership of the Certass Trade Association included. Members get a business profile on Certified Competent, a directory where each listing shows a score and an extract from a homeowner's review.

Whichever you join, check your listing: the areas you cover, the phone number and the products you fit. A homeowner who reached you through a scheme's search has already decided that registration matters, so ring them back first.

2. Put the certificate and the insurance-backed guarantee in every quote

Two questions decide whether a homeowner trusts a window quote, and you can answer both on paper. Will the work be signed off? And what happens to the guarantee if the firm stops trading?

The first answer is the compliance certificate. FENSA calls its version a FENSA certificate and tells homeowners it's essential when selling the property (homeowners). Certass points out that whichever scheme an installer uses, the homeowner gets a Building Regulations Compliance Certificate that serves the same purpose. So when a homeowner asks if you're "FENSA registered" and you're with Certass, answer what they're really asking: yes, the job will be certified.

The second is the insurance-backed guarantee. gov.uk says competent person schemes have insurance-backed warranties and complaints procedures if there's a problem with the work. FENSA says it checks that every FENSA Approved Installer's guarantee is insured, and that the insurance covers the installer's written guarantee if the installer ceases to trade. It also says a FENSA certificate is proof of compliance, not a guarantee. They're two separate documents, and your quote should name both, with how long the guarantee lasts and who insures it.

3. Get listed by the companies whose products you fit

Some of the companies whose products you fit market to homeowners, and pass the enquiries on to the businesses they approve. Liniar, for example, says it supplies independent specialist manufacturers and resellers across the UK (Liniar for installers), with a postcode search on its website for finding the nearest one. As published on 2 Nov 2026:

• Liniar Approved is for fabricators. Its benefits include being featured on Liniar's website as a supplier and receiving direct leads generated by Liniar, and a fabricator can apply after three months as a Liniar customer.
• Climadoor's approved installer scheme offers door fitters a steady stream of customer enquiries, 5% off its standard pricing and a dedicated account manager. The application asks for your experience, references and a link to your Checkatrade page, and may lead to a short phone interview.
• The Residence Collection has a postcode search for homeowners to find their nearest Residence installer.

Ask your fabricator and your door supplier three questions. Do homeowners contact you? How do you decide who gets each enquiry? What would it take for us to get some? A scheme tied to one brand only pays if you'd fit that brand anyway.

4. Turn showroom visits into home surveys

A showroom lets a homeowner do what a brochure can't: open a tilt-and-turn, swing a composite door shut and hold a colour sample against their own brick. It also makes you what Google calls a hybrid business, one that serves customers at its address and also visits them. A hybrid business can show its address and set up to 20 service areas, within about two hours' drive of its base. Google's guidelines say a business showing its address should keep permanent signage there. Without it, hide the address and set up as a service-area business. Use the name on your sign and nothing more. The guidelines don't allow unnecessary words in a business name, so a listing reading "Fernhallow Windows Double Glazing Doncaster" breaks them.

Give every visitor a reason to book a survey before they go. Note the rooms and doors they talk about, ask for a photo of the front of the house, and offer two survey times. A visitor who leaves with a brochure has seen your stock. One who leaves with a survey booked has started buying from you.

5. Ask every customer for a Google review, at the same two moments

Google's page on local ranking says results depend mainly on relevance, distance and prominence, meaning how well known a business is, which includes how many reviews it has. It also says: "There's no way to request or pay for a better local ranking on Google."

Window jobs give you two natural moments to ask. The first is when the last snag is done and the fitters have cleared up. The second is when the compliance certificate should have reached the homeowner: a short message to say so, with your review link or QR code, which Google suggests, reaches someone who has lived with the new windows for a few weeks.

Ask everyone at those moments, not just the customers you expect to be pleased. Google's contribution policy rules out discounts or free goods for reviews, selectively asking for positive ones and pressing customers to review while they're on your premises, so leave the showroom counter out of it. Since 6 April 2025, commissioning a fake review, or one that hides an incentive, has been a banned practice under the Digital Markets, Competition and Consumers Act 2024, according to the CMA's guidance on unfair commercial practices.

Photograph finished fronts from the pavement, with the homeowner's permission and the house number out of shot. Google says photos and videos let you show what you offer, and the same photos work in your quotes.

6. Go back to the street you've just fitted

New windows and a new front door are on show to the whole street, and the house next door was probably built the same year as the one you're working on. With your customer's agreement, put a note through the neighbours' doors while you're fitting, saying which house you're working on and how to reach you. If you knock instead, leave when you're asked: the CMA's guidance lists ignoring a request to leave a consumer's home, or not to come back, as a banned practice.

Then keep a list of what each customer didn't replace: the back door, the patio doors, the windows at the back. If you'll email or text them about it, check the ICO's soft opt-in rules first, which our guide to getting more home improvement customers sets out.

Are Checkatrade and Bark worth it for window fitters?

The two charge in opposite ways. As published on 2 Nov 2026, Checkatrade sells a membership. Its pricing page lists a free profile that collects reviews, its tick and a place in the directory for £30 a month, and Growth, from £59 a month, for a steady flow of enquiries at a fixed monthly cost. Fixed plans last 12 months, and a business passes up to 12 checks before approval.

Bark charges per contact instead. Its pricing page shows what each request costs in credits before you answer it, and credits bought from 1 November 2025 expire three months after purchase. Under its terms, a homeowner's general request goes to up to five professionals, and credits spent on a contact with an invalid phone number come back if you report it within seven days.

A free profile is worth having for the reviews, and some manufacturers look for one: Climadoor's application asks for your Checkatrade page. Paying for enquiries is a different call. On Bark, a whole-house job can have up to five firms responding, and every survey you book costs your surveyor an evening. Our guide to what trades pay on Bark, Checkatrade and MyBuilder works out what one won job costs on each.

Do Google and Facebook ads work for double glazing leads?

They can, if you treat them as two different jobs. Google search ads catch homeowners already typing "composite doors" and a town, so the intent is high and the volume is capped by how many people search. Facebook and Instagram reach homeowners who haven't started looking, so you get more enquiries and need a form that sorts them.

What makes window ads pay:

1. No promises the job can't keep. The ASA's advice on lead generation marketing records rulings against window and double glazing ads offering "funding", "scrappage" and "grants". A "half price if you sign today" ad has its own problem: the CMA's guidance lists falsely claiming an offer is available only for a limited time, to rush a decision, as a banned practice.
2. A page for each product. Sash windows, composite doors and bifolds each get their own landing page, with real photos from your jobs and the areas you cover.
3. A form that asks what a surveyor needs. Homeowner or not, how many windows and doors, roughly when the current ones went in, and when they want the work done. Our guide to lead qualification questions covers which belong on the form.
4. A reply within minutes. See speed to lead for why the first hour matters.
5. Counting surveys and orders, not form fills. Tell the ad platforms which enquiries booked a survey; our guide to the lead feedback loop shows how.

When should a window company buy leads?

When your fitting teams have gaps the routes above can't fill yet, someone can call a new enquiry within the hour, and you know how many of your surveys turn into orders. Without that last number, you can't tell a good price per lead from a bad one.

Before you buy, ask who else gets each lead, what happens to a bad number, whether you can choose the jobs (full houses, single doors, repairs) and whether the supplier needs your FENSA or Certass registration. Our comparison of 14 UK double glazing lead suppliers sets out what each one publishes on these questions, and our guide to what double glazing leads cost covers when buying is the wrong move. For the first question, see exclusive vs shared leads.

How do you compare routes on cost per order?

Count everything a route costs, including scheme fees and the hours you put in:

Cost per order = (fees, ad spend or lead costs for the route + hours on the route × what an hour of your time costs) ÷ orders from the route

Here's Fernhallow Windows, an invented installer, over six months, valuing an hour at £35. Every number is made up for illustration. None is POCKLA data, any supplier's data or a forecast.

In this made-up half-year, the listings and reviews are cheapest per order but stop at four: Fernhallow can't make more homeowners search FENSA's site. The marketplace books surveys at a cost close to the ads, but fewer of them become orders. The ads and the bought leads are close, and one order either way swaps them: at six orders, the bought leads cost £683 each, and at seven, the ads cost £554.

Leave the hours out and the listings look almost free. They aren't: their 30 hours went on asking for reviews, following up showroom visits and keeping two profiles up to date.

Your own version needs three habits: a "where did you find us?" question on every first call, a monthly note of what each route took in money and hours, and the route written on every order form. Six months is a fair test for windows, since a survey can turn into an order weeks later. Then hold each route's cost per order up against the margin on a typical order. Our guide to cost per lead vs cost per job shows which stage to fix when a route costs too much.

What should you say on the first call? A window and door script

Whichever route an enquiry came from, the first call decides whether it becomes a survey. Here's a script for Fernhallow Windows, the invented installer above, and Karen, an invented homeowner. Change the words until they sound like you, and don't ask again what the form already told you.

1. Open

"Hi, is that Karen? It's Dan from Fernhallow Windows. You asked about new windows for your house in Doncaster yesterday afternoon. Have you got five minutes now, or is this evening better?"

If neither works, agree a time and ring off.

2. Check what the form said

"You said it's a 1960s semi with eight uPVC windows, put in around 2000, and you're thinking about the next few months. Is that still right?"

3. Ask what the form couldn't

1. "What's made you start looking now?" Draughts, a door that won't lock properly and an upcoming sale each send the survey somewhere different.
2. "Is it just the windows, or are the doors on the list too?" A back door added now gets measured at the survey, not on a second visit.
3. "Have you got a colour in mind: white, a wood-effect finish, grey?" Colour and finish change the price, so it's better to know before the surveyor arrives.
4. "Is the house listed, or in a conservation area?" If it is, the Planning Portal strongly advises checking with the local planning authority before any work, so find out before you design anything.
5. "Who else will be deciding? Could they be there for the survey?"

4. If they want a price on the phone

"I'd only be guessing. We measure every opening before we price, because sizes, style and colour all move it. The survey takes about an hour, and you'll have a written quote afterwards."

5. If they ask whether you're FENSA registered

"Yes. When the job's done, you'll get a FENSA certificate to show it meets building regulations, and our guarantee is insurance-backed, so it's covered even if we stopped trading."

If you're with Certass instead:

"We're registered with Certass, which is on the government's list of schemes for replacement windows, alongside FENSA. You'll get a Building Regulations Compliance Certificate when the job's done, which does the same job."

Say only what's true for your firm. Check your scheme's rules and your guarantee's terms before either line goes into your script.

6. Book the survey, and say what won't happen

"Could you both make Tuesday at six, or Saturday at ten? Our surveyor will measure every window and door and go through the styles with you. Our quotes hold for 30 days, so there's no deciding on the night."

The 30 days are Fernhallow's invented terms; use your own. The point is the last sentence: it tells the homeowner there's no deadline to brace for. If your quotes do have an end date, give the real one. The CMA's guidance lists a false time limit, used to rush a decision, as a banned practice.

7. If they're not ready

"That's fine. Shall I send you some photos of doors we've fitted near you, and ring you back in a couple of weeks?"

Ring back once, when you said you would. If the answer is no, take them off your list.

Where POCKLA fits

POCKLA is one of the paid routes in the table. We run our own Meta and Google campaigns for homeowners replacing their windows and doors, and sell each of our double glazing leads once, to one buyer. You choose the postcodes and the jobs: casement, sash, tilt-and-turn and bay windows, and composite, French, patio and bifold doors. Repair-only jobs, commercial projects and enquiries that depend on finance or a grant aren't sent, and conservatories are a separate lead.

We check the phone number live and the postcode against your area. The rest is the homeowner's own answers on the form: the property and its age, whether it's listed or in a conservation area, the windows there now, how many they want and when. If you advertise FENSA or Certass registration, we check it before your campaign goes live.

Follow-up runs on WhatsApp under your brand's number, or by SMS with a personalised link if you'd rather. Leads land in your CRM, or in POCKLA Desk if you don't use one, and calls you make from Desk come with free call analytics. An invalid number is returned, however long after delivery you find it. Pricing is an indicative £20–£50 per qualified web lead, a range rather than a quote, and your exact figure is set on a call. You pay no setup fee or monthly fee, and sign up to no minimum term (pricing). Live transfers are priced on your criteria.

Put us through the cost-per-order sum like any other route. If our leads don't come in below what an order earns you, the free routes above are the better use of your money.