How do we choose a heating engineer or plumber?

In rural Ayrshire there may only be a handful of firms within reach, and the good ones are busy all winter. That makes it tempting to take whoever can come soonest. A few checks first take an evening and save a lot of grief.

The most important check is not a review score but a registration. Each fuel has its own scheme, and the Scottish building standards guidance on combustion appliances names them: Gas Safe Register for gas, OFTEC for oil, HETAS for solid fuel.

Which registration should they have?

It depends on the job. LPG and gas appliance work must be done by a Gas Safe registered engineer. Oil boilers, burners, fuel lines and tanks are for an OFTEC-registered technician, and OFTEC's registered technician search lets you check a firm. HETAS registers installers of solid fuel and biomass appliances. For heat pumps, the installer and product must be MCS certified for many UK incentives, including the Home Energy Scotland Grant and Loan.

A firm may hold more than one registration, but check that the one you need covers the type of work, not just the company name.

How do we find someone trustworthy?

The Scotland section of Citizens Advice has a guide to finding a trader you can trust, which suggests starting with your council's approved trader list or Trading Standards pages, then trying schemes such as TrustMark and Scotland's Approved Trader Directory. If a trader says they belong to a scheme or trade association, check that on the scheme's own website.

In South Ayrshire, the council's Trusted Trader scheme says its traders are individually vetted by South Ayrshire Trading Standards officers, including insurance and complaint checks. For East or North Ayrshire, search your council's website for approved traders.

How many quotes should we get?

For a heat pump, Home Energy Scotland's installation checklist recommends quotes from at least three qualified installers, each with a breakdown of costs and specifications and an explanation of how they calculated your heat demand. It also suggests checking warranty length and payment and deposit terms. The same habits work for any heating job.

What should a good firm's paperwork show?

A clear list of what the business does, which areas it covers, and which registrations it holds. The page shown in the reference link below is one way a firm lays this out. It belongs to a heating company in Pennsylvania in the United States, not in Scotland, so treat it only as an example of layout and never as a firm to call.

What to look at first

1. The registration that matches your fuel or system.
2. That registration, checked on the scheme's own search.
3. Whether the firm is on a council-backed trader list.
4. Three written quotes with the same scope.
5. Warranty, payment stages and deposit, in writing.

Yours to do, and theirs

You can

• Check registrations on the OFTEC, Gas Safe, HETAS or MCS websites.
• Ask for written quotes and compare like with like.
• Keep invoices, certificates and warranties together.

Leave to them

• The registered engineer does the fuel, flue and appliance work.
• Council Trading Standards and Citizens Advice help if a job goes wrong.

In short

Match the engineer's registration to your fuel first, check it on the scheme's own website, then compare written quotes. Council-backed trader schemes and Citizens Advice are there to help you choose and to help if something goes wrong.

Also asked about this

Does an oil boiler service have to be done by OFTEC?

OFTEC says servicing should always be done by a competent person; using an OFTEC-registered technician is the straightforward way to make sure. See who should service the oil boiler.

Can one engineer handle a heat pump and the old oil boiler?

Only if they hold both MCS certification and OFTEC registration for that work. See should we swap the oil boiler for a heat pump.

Who checks a carbon monoxide alarm installation?

A battery alarm you can fit yourself following the guidance; see do we need a carbon monoxide alarm. Mains-wired alarms should be fitted by a qualified electrician.

What if the trader is not on any list?

That is not proof of a problem, but ask for references and check any registration and membership they claim on the scheme's own website.

Sources, checked 5 November 2026

1. Scottish Government — Technical Handbook (Domestic), April 2026, 3.17 Combustion appliances, safe operation
2. OFTEC — Why choose an OFTEC registered technician
3. MCS — Consumers
4. Citizens Advice — Find a trader and check you can trust them
5. South Ayrshire Trusted Trader — Vetting process
6. Home Energy Scotland — Heat pump installation checklist and guide
7. HETAS — Consumer advice