Quick answer: Double glazing sales has a long history of pressure tactics, fake urgency, and statements that aren’t quite true. Many of the worst behaviours are now illegal under the DMCC Act 2024 (in force 6 April 2025) with penalties up to 10% of global turnover. Here are the 7 most common lies you’ll hear in 2026, why each one is wrong, and exactly what to say back.
If you recognise any of these, you don’t have a “tough negotiator” on your hands — you have an installer relying on tactics that lose against an informed customer every time.
Lie #1: “This price is only valid today”
What they say: “I can offer you this price now, but if I leave the house without a signed contract, the discount disappears.”
The reality: Almost always false. Manufacturers and fitting teams don’t change prices day-to-day, and most reps have 10–20% headroom on the headline price. The “today only” line is the oldest pressure tactic in the book.
The legal angle: Under the DMCC Act 2024 and the older Consumer Protection from Unfair Trading Regulations 2008, falsely claiming a price is only available for a limited time is a misleading commercial practice. Trading Standards can prosecute.
What to say back: “I appreciate the offer. I never sign anything in the same visit on principle. Please put the price in writing and email it through, valid for 14 days. If it’s a real price you’ll be happy to do that. If it’s not, I’m fine to walk away.” Watch the headline price stay valid 9 times out of 10.
Lie #2: “We’ve got a fitting team in your area next week — last slot”
What they say: “By coincidence, we have a team finishing a job nearby and they’ve got availability for one more job. If you book today we can save you the call-out.”
The reality: Manufactured urgency. Fitting teams travel routinely; “in your area next week” is a default script. There’s also no separate “call-out” charge that gets waived — installs are quoted as a complete package.
The legal angle: Same as #1 — misleading creation of urgency is a banned commercial practice under DMCC Act 2024.
What to say back: “Whenever you can fit me in is fine. I’m not in a rush.” Watch the urgency disappear — and the price stay the same.
Lie #3: “Lifetime guarantee covers everything”
What they say: “Our windows come with a lifetime guarantee — you’ll never need to worry about them again.”
The reality: Three layers of fine print:
- “Lifetime” usually means the company’s lifetime, not yours. Several major UK installers have entered administration recently; their lifetime guarantees disappeared overnight.
- Even when active, “lifetime” usually applies only to the frame — sealed glass units typically have separate 5–10 year warranties.
- Common exclusions: cosmetic damage, gasket wear, hardware after year 5, anything caused by “normal use”.
The legal angle: The DMCC Act 2024 specifically bans “misleading omissions” — making a claim (“lifetime”) without explaining the material terms (“of the company’s existence, frame only, excludes seals after 10 years”) is now an offence.
What to say back: “What’s the actual term in years? What does it cover specifically? Is it backed by an insurance-backed guarantee like Installsure or QANW? Can I see the warranty document before I sign?” The honest answer is usually “10 years frame, 5 years sealed unit, IBG Installsure-backed” — fine. The dishonest answer is hand-waving — walk away.
Lie #4: “Our windows are A++ rated, the highest you can buy”
What they say: “Our windows are A++ rated — the best you can get.”
The reality: A++ is impressive-sounding but doesn’t mean what most buyers think. The Window Energy Rating (WER) combines heat loss with solar gain, and a south-facing A++ window can have a worse U-value than a north-facing A-rated window. U-value is what actually keeps your house warm in February; WER is partly a marketing label. See our U-values & WER guide.
What to say back: “What’s the Uw — whole-window U-value — in W/m²K? And is it argon-filled with warm-edge spacers and low-E glass?” If they don’t know the answer immediately, they’re selling on price not specification. Real A++ products typically have Uw of 0.7–0.9; “A++” labels with Uw of 1.4 exist and they’re not actually premium.
Lie #5: “You don’t need [trickle vents / IBG / written quote]”
What they say: Variations on “you don’t really need that — it’s optional” for things that are actually required by law or industry standard.
The reality — three big “you do need it”:
- Trickle vents — required by Building Regs Part F since June 2022 in habitable rooms. Skipping them voids the FENSA cert and surfaces when you sell. Full guide here.
- Insurance-backed guarantee (IBG) — not legally required but FENSA / CertAss / TrustMark all require their members to offer one. Without it your warranty dies if the company folds. Full guide here.
- Written quote with itemised pricing — basic consumer practice. A salesperson refusing this is hiding something.
What to say back: Get any “you don’t need it” claim in writing on company letterhead. Watch the claim quietly retract.
Lie #6: “We’re [Anglian / Safestyle / Everest] — backed by a national company”
What they say: “We’re a major national brand — you’ve got the security of a big company behind you.”
The reality: Anglian, Safestyle and Everest are now all owned by ASHI Group (Alchemy Partners). Safestyle entered administration in October 2023; Everest has been through administration twice in the last decade. The “backed by a national company” promise from a Safestyle salesperson in 2023 turned out to mean very little when the company collapsed weeks later. The brand badge on the van and the financial security behind it are not the same thing.
What to say back: “Who owns the company that’s contracting with me? Is the warranty backed by an insurance-backed guarantee from Installsure or QANW that survives if the company changes hands or fails?” If they don’t have a clear answer about ownership and IBG, the “national brand” promise is decorative.
Lie #7: “If you sign now, we’ll knock £2,000 off”
What they say: “Look — I shouldn’t do this, but if you sign tonight I can give you a £2,000 discount. Otherwise the price goes back up.”
The reality: The “£2,000 discount” was already built into the original price as headroom. Industry research over decades shows that quoted prices for in-home double glazing sales are typically inflated 30–50% above the company’s “best available” price specifically to allow for these dramatic discount-now reveals.
The legal angle: Inflated “was £X / now £Y” framing without genuine prior pricing is misleading under DMCC Act 2024. The CMA has been actively prosecuting this in adjacent industries.
What to say back: “Thanks. I never sign on the day. Please put the £2,000-off price in writing and email me, valid for 14 days. If it’s a real price the offer survives the email.” Most reps will agree under pressure rather than walk away.
How to handle high-pressure visits in general
- Set the rule before they arrive: “I never sign anything in the same visit. I’ll consider written quotes for 7+ days.” Say this on the phone when booking the visit; many reps will just decline to come, which is information.
- Don’t offer tea on arrival. Sounds rude; it shortens the visit. Tea = 90 minutes; no tea = 45 minutes.
- Have your spouse/partner deliberately “available later” as the decision-making excuse. A second decision-maker not in the room means no decision is possible.
- Never give a deposit on the visit. Even with 14-day cancellation rights, getting a deposit back is admin. Don’t pay until you’ve thought about it for at least 3 days.
- Ask explicitly for an itemised quote: per-window cost, fitting cost, scaffolding/access, IBG cost, FENSA cost, VAT. Quotes that bundle everything into one number are hiding things.
- If the rep refuses to leave: a clear “I’d like you to leave now please” is enough. Refusing to leave is now a specific aggressive practice offence under DMCC Act 2024.
Your statutory protections summarised
- 14-day cooling-off period — Consumer Contracts Regulations 2013. Refundable in full. Full guide here.
- Aggressive sales tactics ban — DMCC Act 2024, in force April 2025. Reportable to Trading Standards / CMA.
- Misleading omissions ban — DMCC Act 2024. “Lifetime warranty” without explaining the term is now actionable.
- Drip pricing ban — DMCC Act 2024. Headline price must include all unavoidable fees.
- Section 75 Consumer Credit Act — pay any deposit by credit card; the card provider becomes jointly liable if the company fails to deliver.
- Consumer Rights Act 2015 — ongoing rights to faulty-install rejection or replacement, separate from any warranty.
Frequently asked questions
Are all double glazing salespeople like this?
No — and the picture is improving. Many independent local installers run quote-based businesses with no commission-driven reps; they put a price on paper and stand by it. The 7 lies above are most associated with the legacy national brands (Safestyle, Anglian, Everest) and franchise operations using commissioned door-to-door sales models. The local-installer model is usually the saner buying experience.
Can I record the sales visit?
Yes — in your own home, you can record audio/video without consent under UK law. Useful if you suspect aggressive tactics; provides evidence if you need to escalate to Trading Standards. Most reps will moderate behaviour if told upfront they’re being recorded.
What’s the worst tactic I should report?
Refusing to leave when asked is the most serious — that’s a specific aggressive-practice offence under DMCC Act 2024. Other reportable behaviours: targeting elderly or vulnerable customers, false “we’re going bust so prices are slashed” claims, and any explicit “if you don’t sign now I’ll lose my job” emotional manipulation.
Where do I report aggressive sales tactics?
Citizens Advice consumer helpline (0808 223 1133) — they escalate to Trading Standards. For DMCC Act breaches you can also report directly to the CMA. FENSA’s complaints process for FENSA-registered installers. None of these cost you anything.
If I’ve already signed under pressure, can I get out of it?
Within 14 days of an in-home signing: yes, automatically — see cancellation rights guide. Beyond 14 days: harder, but if the company breached the cancellation-information rules (didn’t give you the model cancellation form on signing) the clock can extend up to 12 months. Speak to Citizens Advice.
Get pressure-free quotes from local installers
Our quote service connects you with up to 4 vetted FENSA-registered local installers in 24 hours. We drop installers from our network if their reps use any of the 7 tactics above — homeowners are encouraged to report them to us. Free, no obligation, no high-pressure sales pitch.
Related: Your Cancellation Rights · Before You Sign a Contract · IBGs Decoded
Sources: DMCC Act 2024 (in force 6 April 2025), CMA208 unfair commercial practices guidance, Consumer Protection from Unfair Trading Regulations 2008, Citizens Advice consumer rights guidance, Which? double glazing buyer guides, ASA / CAP code on aggressive selling, MoneySavingExpert glazing forum tactic-tracking. Anglian-Safestyle administration: FCA notice October 2023; Everest brand acquisition by Anglian, May 2024. Last reviewed: April 2026.
From homeowners like you
Quick, clear, no pressure. I asked the 6 questions from the buyer's guide and it genuinely filtered out the weaker installers. Picked the local one with the longest track record.
Tenement flat in the West End — a lot of installers wouldn't quote because of access, but Findfitter matched me with one who specialises in G1-G3 flats. Spot on.
Really helpful comparing finance options — two of the four installers offered 0% APR. Picked the one with a 15-year frame warranty and the transparent breakdown.