Register and certification
- No MCS certification number, or one you cannot find on the register. Without MCS certification, the firm cannot apply for the grant for you and the installation will not get an MCS certificate.
- Certified, but not for heat pumps. Certification is per technology. A firm listed only for solar panels is not certified to fit your heat pump.
- Not registered for the Boiler Upgrade Scheme, while promising you the grant. The register shows this as Yes or No.
The grant
- A request to pay the grant amount yourself and claim it back. The grant is a voucher in the installer's name, deducted from the price. Since the 2026 rules, the installer may not ask you for that amount unless the application is refused or the voucher revoked.
- A grant promised as a certainty. Ofgem decides each application, so no installer can promise the outcome.
- A grant figure with no conditions. The grant is £7,500 for most homes that qualify, with rules about ownership and the heating replaced. The Advertising Standards Authority has upheld complaints about grant adverts that did not make eligibility clear.
- Pressure to apply before you have a design. The application starts the grant's clock; it should follow a survey and a quote you are happy with.
Claims and logos
- A heat pump offered at no cost. Under the Digital Markets, Competition and Consumers Act 2024, describing a product as costing nothing when the consumer has to pay something is banned outright. Ask what you will actually pay.
- Claims of approval by government. There is no such status for heat pump installers. Falsely claiming approval or endorsement by a public body is also banned outright under the same Act.
- A trust mark the firm is not entitled to. Showing a trust mark without authorisation is banned too. TrustMark warns that some tradespeople display its logo when they are not registered; check on its site.
- Reviews that look too good. Fake reviews, and reviews that hide that they were paid for or rewarded, are banned. See reading reviews.
- Savings figures with no basis. The ASA upheld a complaint against an "up to" heat pump savings advert in March 2026. Ask how any savings figure was worked out.
Pressure
- A price that is only good if you sign today. Real deadlines exist in the grant scheme, such as an application date for the higher oil and LPG rate, but they are published and checkable. A firm's own "sign now" price is not one of them.
- Reluctance to put things in writing. The heat-loss design, the itemised quote and the terms should all be on paper before you sign.
- A large deposit, unprotected. Ask how any deposit is protected under the firm's consumer code. See deposits and payments.
The paperwork
- No heat-loss figures. A heat pump should be sized to a calculation. A quote with a unit size but no heat-loss figures is a guess.
- No mention of where the outdoor unit goes, or of the MCS 020 a) sound calculation needed for it in England.
- No written cancellation terms. RECC says that in many cases you have 14 days to cancel; your contract should say what applies. See cancelling a contract.
None of these signs proves a firm is dishonest; some are oversights. But each one is a good reason to stop, ask, and check before going further. The check sheet covers the ones that can be confirmed from outside.
What to do if you spot one
- Pause. You do not need to decide on the spot.
- Run the checks that can be done from outside: the MCS register, the consumer code's site, TrustMark if claimed.
- Ask the firm, in writing, about the specific concern.
- If the answer does not satisfy you, choose another certified firm. The register lists plenty.
Checking after you sign
Warning signs can appear after a contract is signed: a request for the grant amount, a change of installer, a delay that threatens the grant voucher's deadline. Each has a route. The grant rule is in your favour; a change of installer should be checked on the register; and a delay is worth raising early in writing. If things go wrong, the complaints and disputes guide sets out the order to go in.
Signs that are not warning signs
Some things worry people unnecessarily. A firm based outside your town is normal; many installers cover wide regions. A wait of a few weeks for a survey is common. A quote higher than another is not suspicious in itself if it prices more work. And a firm that asks for time to prepare a proper design is doing its job. The signs above are about missing certification, misleading claims and pressure, not about distance or price.
When a doorstep visit turns into a sale
If a firm arrives unannounced, or a visit you agreed to turns into pressure to sign that day, stop. Ask for the quote, the design and the terms in writing and say you will reply once you have checked them. A legitimate firm will leave the paperwork. A contract made in your home normally carries a cancellation period, explained in cancelling a contract, but it is far easier not to sign than to unpick a contract afterwards. Write down the firm's name, the date and what was said; if the pressure was serious, you can report it to Trading Standards through Citizens Advice.
Most of these signs show up in the paperwork, so read them alongside comparing quotes. The checks in check an installer and the questions in survey visit questions are the surest way to spot them before you commit to anything.