How we chose
We started from the boiler repair firms Google Maps shows across Telford. Scheme memberships were sourced from the Gas Safe Register, each firm's own website and platforms such as Checkatrade and Which? Trusted Traders [1]. Each business must first meet our basic checks: it is who it says it is, it is trading today and can be reached, and it shows the Gas Safe position this trade needs. Eight firms met all three. We looked first at what customers say, then qualifications, then whether the firm has traded two years or more and whether its cover is stated, then pricing clarity and website detail. All evidence is dated early September 2026.
How to hire
Anyone who touches your gas boiler must be on the Gas Safe Register; that is the law, not a nice-to-have [1] [2]. When the engineer arrives, ask for the Gas Safe card and read it: photo, licence number, expiry date, and the categories on the back showing which appliances they may work on. You can check the licence number on the Gas Safe Register online before they start [1]. If the card never appears, do not let them open the boiler.
A few other badges matter in this trade, and each means something different. Manufacturer accreditation, such as Worcester Bosch accredited installer status held by several firms in our table, shows extra training on that brand and can unlock longer guarantees on its boilers [3]. BESA membership marks a building-services trade body. HETAS and OFTEC belong to solid-fuel and oil heating, so they only count if your home runs on those fuels [4] [5]. Stars on Checkatrade or Which? Trusted Traders describe customer experience, not competence, so read them alongside the register, never instead of it.
Get two or three quotes on the same written scope and insist each one shows the same lines: call-out or diagnosis fee and whether it is credited against the repair, hourly or fixed labour, parts specified by brand and whether new or pattern, travel and parking, VAT shown as included or added, guarantee length, and payment terms. A quote missing half these lines is not cheaper, it is unfinished. Never accept a price that only exists in a phone call.
For a breakdown, help the engineer help you: boiler make and model, the fault code on the display, what the pressure gauge reads, any new noises, and when it last worked. Ask what the diagnosis visit covers, what an evening or weekend call-out adds, and how fast parts for your model can be had. Readers with a landlord certificate due should know the certificate and the service are different jobs: the certificate checks safety, the service cleans and adjusts, and booking both in one visit usually costs less [7].
Monthly cover plans suit older boilers out of warranty, spreading services and breakdowns across the year, while a newer boiler under manufacturer warranty usually needs only its annual service to keep that warranty valid [6]. Either way, read the exclusions before you sign: parts and labour included or call-outs only, excess per claim, and whether your boiler's age or make is covered at all.
Good paperwork at the end looks like this: an itemised invoice matching the quote, the guarantee in writing with its length and what it covers, and the service record filled in, since missed services can void a manufacturer warranty [6]. Landlords must hold a current gas safety record for every appliance and give tenants a copy within four weeks of the check [7]. If a job goes wrong and the firm will not put it right, Citizens Advice sets out your next steps [9]. Pay by card where you can, and hold back nothing once the paperwork is in your hands.
Telford and Wrekin adds its own wrinkles. A replacement boiler is building work, so even where no planning permission is needed the job may still need building-regulations approval, and the council advises contacting its Building Control team before work starts [11] [13]. On most Telford streets the engineer's notification through the competent-person rules covers the paperwork [11]. Listed buildings and the borough's eight conservation areas, from Wellington and Newport to Horsehay and the Severn Gorge, are different: external changes such as a new flue route can need permission, and the Gorge carries extra controls over even minor changes, so check with the council before the engineer drills [12]. Jobs come from estates such as Lawley as well as streets in Wellington, Dawley, Madeley and around Ironbridge, so mention access and parking when you first call.
A typical job runs in five stages. You describe the fault or the service due, with the boiler make and model to hand, and agree whether the first visit is diagnosis or a fixed repair. The engineer attends, confirms the fault and prices the work before going beyond testing. You approve a written quote showing labour, parts and VAT, then the work goes ahead, ending with the boiler fired, tested and recommissioned. Finally the paperwork lands: the itemised invoice, the written guarantee and, for a replacement, the compliance certificate that follows the engineer's notification [11].
Handle the money in the open. A small deposit for ordered parts is normal on bigger jobs; the full amount in cash before work starts is not, and that demand sits among the red flags below. Pay the balance by card once the invoice, guarantee and service record are in your hands, then file every page with the boiler manual and put the next service date in your calendar the same day.
Pricing
As of autumn 2026, a one-off gas boiler service typically costs £80–£120, averaging about £100, with oil services a touch lower at £75–£110 [6]. That visit covers inspection, controls, pressure, leaks and the flue, and it keeps most manufacturer warranties valid. Treat anything far below the range with suspicion rather than delight: a rushed service that voids your warranty is the dearest kind.
For repairs, a call-out with diagnosis typically runs £60–£120, often credited against the job if you go ahead, and most boiler repairs land between £120 and £450 including parts [8]. Wider national guides stretch typical repairs to £750 and emergency call-outs higher still [6]. Out-of-hours attendance alone can cost £120–£250 before parts [8].
Landlords need the annual gas safety record on top: roughly £60–£90 for a single-appliance property and £80–£150 where two or three appliances need checking, with a combined service and certificate visit often costing £100–£150 together [7]. Each extra appliance adds time on site, so count every gas appliance in the property when you compare quotes.
Three things move every price: how many appliances are involved, access and timing, with autumn the peak season as renewals bunch before winter [7]. Midlands labour sits around the national average rather than the London premium [8]. Whatever the job, the quote must state whether VAT is included or added, list parts and labour separately, and put the guarantee in writing before anyone starts.
A service stays near the middle of the range when the boiler is easy to reach with clear space around it and a recent service history behind it, and climbs when access is awkward, the flue run is long, or faults found on the day need parts [6].
Repair bills turn on three things: whether the fault needs a minor seal or a major board or fan, how fast the part for your model can be had, and when the engineer attends, since evening and weekend call-outs carry a premium before parts [8].
Certificate prices move with the number of gas appliances the engineer must check, so count the boiler, hob and fire before you compare quotes [7].
A like-for-like combi swap usually lands lowest, around £2,500–£4,000 supplied and fitted, while moving the boiler, changing its type or upgrading radiators and controls pushes the total up, with full installations typically £3,000–£15,000 including labour at £1,000–£2,000, all March 2026 figures [10]. Fuel narrows the field too: oil boilers need an OFTEC technician and solid-fuel ones a HETAS engineer, so those homes choose from fewer firms [4] [5].
Red flags
The engineer cannot show a Gas Safe card when asked, or the card's categories do not cover boilers.
They quote a repair price without looking at the boiler or hearing the fault described.
The price exists only in conversation and never arrives as a written, itemised quote.
They demand the full amount in cash before any work has started.
The quote never says whether VAT is included or added on top.
No invoice, guarantee or service record is offered once the job is done.
An unusually cheap certificate turns out to cover the boiler alone while the hob and fire go unchecked.
The business name, address and phone number appear nowhere on the quote, the invoice or the van.
They press you to agree on the doorstep before any written quote arrives.
Corrections and business responses
Tell us what needs checking, or ask to claim a listing and reply to an assessment.