How to check a heat pump installer: MCS, TrustMark and what to ask

The three minute check

Do these three things before you accept a quote.

1. MCS register. Go to the MCS Find an installer search at mcscertified.com. Look up the firm and check it is certified for heat pumps.
2. TrustMark register. Search the firm on the TrustMark website. TrustMark is a separate register.
3. Protection. Ask in writing what financial protection covers your deposit and the installation if the firm stops trading.

If a firm fails the first check, you cannot claim the Boiler Upgrade Scheme through it. The scheme needs an MCS installer, and the installer applies on your behalf.

What each register means

Register	What it is	What it does not tell you
MCS	A quality mark for small scale renewable systems, including heat pumps	Whether this design suits your property, or the price is fair
TrustMark	The Government Endorsed Quality Scheme for work in and around the home	Whether it is certified for the heat pump technology you want

This site holds none of these credentials. They appear here only as registers you check yourself.

MCS in plain terms

MCS certified installers follow recognised standards for design, installation and commissioning. The practical output for you is the MCS certificate. MCS says consumers receive it when the installation is complete, accessible through the MCS Installations Database.

Keep the certificate. It supports a grant claim and, later, a sale or a new tenancy file. If an installer says a certificate is “not needed”, that is a reason to look elsewhere.

TrustMark in plain terms

TrustMark describes itself as the Government Endorsed Quality Scheme covering work a consumer chooses to have carried out in or around the home. A TrustMark registered business has been vetted against its standards and has made a commitment to good customer service. It is a general home-improvement register. It does not replace the MCS check for a heat pump grant.

Consumer codes and protection

For years, MCS certification meant a firm had to belong to one of two consumer codes: HIES or RECC. MCS says consumer code membership is no longer mandatory under its redeveloped scheme, and that most installers move onto the redeveloped scheme in phases during 2026.

What MCS does require is financial protection. Under the redeveloped scheme, installers must use a product from MCS’s approved list, which replaces the insurance backed guarantee as the mandatory product. An insurance backed guarantee is an insurance policy that backs the installer’s own guarantee, so you have cover if an MCS certified contractor stops trading during the guarantee term.

So ask four questions in writing:

1. Which consumer code or protection scheme do you belong to?
2. Is my deposit protected, and how?
3. Is the guarantee insurance backed, and for how many years?
4. Who do I complain to if something goes wrong?

Do not take a verbal answer. We have not verified the exact deposit protection limits that individual codes or products offer, so ask the firm to show you the document.

What to ask for in the quote

A quote worth taking seriously comes with:

• a room by room heat loss calculation, so the heat pump is sized to the home
• the make and model of the heat pump and cylinder, and the position of the outdoor unit
• the noise assessment for that position, against the 37.0 dB(A) planning limit
• whether radiators or pipes need to change, and the cost
• the electrical work, and who notifies the network operator
• the grant: that the installer applies for it, and how it appears on the price
• the paperwork on completion: MCS certificate, commissioning record, warranty and instructions

Compare at least two quotes on the same specification. Real costs vary by home. For context, the Energy Saving Trust says around £12,000 for an air source heat pump before any grant, and the Boiler Upgrade Scheme pays £7,500 for air-to-water or £2,500 for air-to-air. See the cost guide.

Using the registers properly

A register check is more useful when you do it with care.

Match the name. Trading names and company names differ. Check that the legal entity on the quote, the website, the MCS entry and the TrustMark entry are the same business. If you cannot match them, ask the firm which entity will sign the contract and hold the guarantee.

Match the technology. MCS certification is by technology. A firm certified for solar panels is not automatically certified for heat pumps. Check heat pumps appear against the firm.

Match the work. If a firm subcontracts the installation, ask who the installing business is and check that business too, since the MCS certificate is issued for the installation.

Check again at contract. Registers change. A status that was current when you first looked may not be on the day you sign, so look once more before you pay a deposit.

Keep a record. Take a dated screenshot of each register entry for your property file. If a dispute arises, you can show what you relied on.

A worked sequence for one quote

Here is how a landlord might use the checks on a single quote. It is a method, not a real case.

1. A quote arrives. You look up the firm on the MCS register and confirm heat pumps are listed.
2. You search TrustMark for the same business name.
3. You email four questions on protection, as listed above, and wait for written answers.
4. You ask for the heat loss calculation and the noise assessment for the chosen position.
5. You compare the specification with a second quote, line by line.
6. You choose, check the registers again, then sign.

If any step comes back empty, the next step waits.

Red flags

Walk away, or at least pause, when you see:

• a firm that cannot be found on the MCS register but says it is “MCS approved”
• a quote without a heat loss calculation, or one produced without anyone visiting
• pressure to sign today, a “limited offer” or a discount tied to a deadline
• a request for a large deposit with no protection in writing
• promises about bills, such as “it will halve your energy costs” without a calculation behind it
• a refusal to issue the MCS certificate
• a “grant” that you are asked to pay for or that the firm will “handle” without your signature on anything

None of these proves bad faith alone. Together, they are the pattern to avoid.

What not to rely on

Do not rely on a firm’s own claims of accreditation, on a logo on a website, or on a mention on this site. We are an independent publisher. We do not install, we do not certify, and a mention is not an endorsement. The registers, and the documents the firm gives you, are the evidence.

When this is not the right answer

If you are not yet sure a heat pump suits the property, do the thinking before the installer calls. Before you install a heat pump in a rental covers consent, planning and electrical checks, and is a heat pump worth it for landlords covers the money. A good installer will also tell you honestly if insulation or a different heating system is the better choice.

Next step

Run your numbers in the landlord heat pump calculator, then, if you want it, send an enquiry. Relevant independent firms will contact you, with no charge to you and no obligation.