The grant rule
Start with the one amount you should not pay. Under the rules in force since April 2026, the installer must deduct the grant from your quote and may not ask you for that amount unless the application is refused or the voucher revoked. A request to pay the full price and "get the grant back" is not how the scheme works. For most homes that qualify, the grant is £7,500.
Deposits
Many installers take a deposit when you sign, often to order equipment. The question to ask is not only how much, but what protects it. Two of the consumer codes Ofgem lists for the grant say:
| Code | What it lists |
|---|---|
| HIES | Deposit and stage payment protection; insurance-backed warranties |
| RECC | A workmanship warranty of at least 2 years with financial protection if the installer fails to fix a problem or stops trading |
Ask the installer how your deposit will be protected, and check the code's own website for what it requires of members.
Stage payments
Larger jobs are often paid in stages: a deposit, a payment when work starts or equipment arrives, and a final payment on completion. A sensible pattern keeps the final payment until the system is commissioned and you have the paperwork: the MCS certificate, the commissioning record and the warranties. Paying everything before the job is finished removes your leverage if something is left undone.
What to agree in writing
- The full price, the grant deduction and the total you pay.
- The deposit, and how it is protected.
- Each stage payment and what triggers it.
- What you owe if the grant application is refused.
- Your cancellation rights: see cancelling a contract.
- The workmanship warranty and who stands behind it.
Keep receipts for every payment with the contract. If a problem ever goes to the consumer code's dispute process, these are the documents it will ask for. The check sheet includes the terms as check ten.
If the grant is refused part-way through
The rules allow the installer to ask you for the grant amount if the application is refused or the voucher revoked. Before paying anything, agree in writing what would happen in that case: whether the work would stop, whether you could cancel, and what you would owe. Applying for the grant before work starts, rather than after, keeps that risk low.
Receipts and records
Ask for a receipt for every payment, showing what it was for and which stage it covers. Keep them with the contract, the quote and the MCS certificate when it arrives. If a dispute ever arises, a clear payment record is often the first thing a consumer code's dispute service asks for.
Paying the final instalment
Before the last payment, check that the system has been commissioned, that you have been shown how to use the controls, and that you have the MCS certificate (or a date for it), the commissioning record and the warranties. Paying once these are in hand is the simplest protection there is.
How you pay
The way you pay can add protection. Paying part of the cost by credit card can give you rights against the card provider as well as the installer if things go wrong, under the Consumer Credit Act, within limits the law sets. Paying in cash, or by bank transfer to an account in a different name from the one on the contract, leaves you with less to fall back on. Ask which payment methods the firm accepts and make sure each receipt names the company on the contract. If a finance agreement is offered, read it separately from the installation contract and check who the lender is.
If a firm presses for a large payment before any equipment is ordered or any work is booked, ask what the money is for and when it will be spent. A clear answer, in writing, is reasonable to expect. A vague one, combined with pressure to pay quickly, belongs on the list of warning signs.