Staged Payments, Not Blind Faith: A Glow-worm Install Deposit Guide

Most homeowners expect to pay something up front for a new boiler. A Glow-worm combi doesn't appear on the driveway by magic, and installers have materials to order, a slot to reserve and a van to fuel. But there's a difference between a reasonable deposit and a leap of faith. In 2026, with plenty of installers competing for work, it pays to know where the line sits — and how to keep your money on the right side of it.

What Counts as a Normal Deposit?

For a straightforward Glow-worm replacement, a deposit of 10–25% of the total job is common. On a £3,000 installation that's £300 to £750. Some firms ask for a larger chunk — 30% or even 50% — particularly if they're ordering a premium model or a hybrid setup. That's not automatically dodgy, but it should be explained clearly and tied to a specific milestone, such as the boiler being ordered or delivered.

Anything above half the job value before a single pipe has been cut deserves a polite question. So does a request for cash with no receipt. Installers have legitimate cash-flow reasons for taking a deposit, but yours should buy you something concrete: a booked date, a written contract and a named boiler model.

The Shape of a Fair Payment Schedule

A fair schedule usually has three or four steps. A booking deposit secures your slot. A materials payment falls due when the boiler and parts are delivered — and you should see them, or at least a delivery note, before that money moves. The final balance is paid after commissioning, when the system has been flushed, the controls are explained and the Benchmark checklist is signed.

If an installer wants the full amount before the first radiator is drained, that's not a deposit — it's a leap. Equally, be wary of a schedule that's vague about what triggers each payment. 'Stage two' means nothing unless it's defined in the paperwork.

Red Flags That Should Stop You Reaching for Your Card

Several patterns should make you pause. A large upfront cash request is the classic. So is a contract that's little more than a scribbled quote with no company address, no Gas Safe registration number and no cancellation terms. If the guarantee is mentioned verbally but not written down — especially an insurance-backed guarantee — assume it doesn't exist.

Other warning signs include pressure to pay before you've seen a written quote, requests to transfer money to a personal account rather than a business one, and a refusal to provide public liability insurance details. None of these guarantee a rogue trader, but together they're a strong hint to walk away.

Paying in a Way That Leaves a Trail

Bank transfer to a business account is normal and traceable. Credit card is better for deposits if the installer accepts it: under Section 75 of the Consumer Credit Act, purchases over £100 are protected if something goes wrong. Debit cards offer chargeback, though it's not a legal right.

Cash is the weakest link. If you must use it, get a signed receipt on company-headed paper every time. Avoid paying for materials directly to a merchant unless you're named on the invoice and can claim the goods if the install goes sideways. Some trade bodies offer deposit protection schemes; ask whether your installer is a member.

Paperwork That Earns Its Keep

Before work begins, insist on an itemised quote that separates labour, boiler, flue, controls and any extras. The contract should set out the payment schedule, start date, completion estimate, cancellation rights and what happens if the boiler is delayed. Check the Gas Safe number and the installer's public liability cover.

For Glow-worm installations, ask how the guarantee will be registered. Most manufacturers' warranties depend on correct commissioning and Benchmark completion. Get the guarantee terms in writing, including whether it's insurance-backed. If the installer is offering an extended warranty through Glow-worm, the paperwork should say so plainly — not just '10 years' on a flyer.

Before the Van Pulls Up

A deposit is a show of good faith, not a blank cheque. A reputable Glow-worm installer will be happy to explain where your money goes and when. If the answers are fuzzy, the schedule is front-loaded or the paperwork is thin, trust your instinct. There are plenty of good installers out there — and in 2026, you don't need to bankroll a mystery to get a warm house.