How we chose
We started from the boiler installers Google Maps shows across Telford. Claimed memberships were sourced from the Gas Safe Register and TrustMark, each firm's own website and the review platforms [3] [7]. Each business must first meet our checks: it is who it says it is, it is trading today and can be reached, and Gas Safe registration is stated for gas work. Six 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
Match the firm to the job first. A boiler installer sizes, fits and commissions replacement boilers and handles the flue, controls and system clean around them; a service engineer owns annual maintenance and breakdowns; a plumber owns water pipework but must not touch gas parts without Gas Safe registration [3] [5]. Say your boiler type, its position, and whether anything moves — same-place swaps, relocations and type changes are priced as different jobs [1].
Check registration before anyone quotes gas work. Fitting a gas boiler is gas work, so the installer must be on the Gas Safe Register — ask to see the ID card and check the number and work categories on the register, since the card alone is not proof [3]. Ask for public liability insurance and a recent local installation you could verify. HSE publishes plain guidance on domestic gas duties that is worth reading before you agree anything [5].
Look past the badge to what sits behind it. TrustMark membership points to checks on trading practices as well as competence, and you can search its register free of charge [7]. Some firms state accreditation from a boiler maker, which can carry a longer manufacturer warranty — ask what warranty length sits behind the badge and get it in writing rather than taking the logo at face value. Whatever the scheme, take the number yourself and confirm it on the register before work starts.
Get two or three itemised written quotes on the same scope: boiler make, model and output, flue kit, filter, controls, flush type, making-good and old-boiler removal as separate lines, plus VAT [1]. A deposit for the ordered boiler is normal; full payment before completion is not. Citizens Advice sets out your rights with traders and the steps if work goes wrong — keep every quote, invoice and certificate together [6].
Agree the shape of the job before anyone lifts a tool. Fix start and finish dates, which rooms lose heating and hot water on which evenings, how making-good and old-boiler removal are handled, and where engineers will park across Telford's tighter streets. Pay a deposit for the ordered boiler by card where you can, keep the final balance until the Benchmark certificate and the Building Regulations notification are in your hands, and keep every quote, invoice and certificate together in case anything needs revisiting [4] [6].
On completion, take the Benchmark commissioning certificate and confirm the Building Regulations notification has been filed through a competent person scheme — the installer does this, not you [4]. Run the heating and hot water with the installer present, register the warranty within any stated deadline, and diary the first annual service. If the paperwork is missing, hold back the final balance until it arrives.
Telford's history shapes the job. The town was designated as Dawley new town in the early sixties and renamed later that decade, joining the market town of Wellington to older townships with new estates laid between them [13]. Expect straightforward swaps on the newer estates, older boilers in awkward spots in the former mining townships such as Dawley and Madeley, and cottages inside the Ironbridge Gorge where the rules tighten. Much of the Gorge sits in a conservation area, and an Article 4 direction removes some permitted development rights for houses there, so even minor external works can need planning permission [8]. Say which town you are in and how old the house is at first contact, and settle whether the flue route or any external change needs the council involved before dates are fixed.
A typical installation runs in a clear order. You describe the boiler, its position and what is wrong with it; the installer visits to measure up, check the flue route and size the replacement from your bathrooms and radiators rather than the old badge. Two or three itemised quotes follow on the same written scope, which you compare line by line before agreeing start and finish dates and paying a deposit for the ordered boiler. On the day the old unit comes out, the system is cleaned, the new boiler, flue, filter and controls go in, and the installer commissions everything with you present. Sign-off means the Benchmark certificate in your hand and the compliance notification filed [4].
A written quote should name the boiler make, model and output, the flue kit, filter, controls, flush type, making-good and removal as separate lines, plus VAT and the payment stages [1]. Because a replacement boiler is notifiable work, an installer on a competent person scheme self-certifies it and notifies the council for you — expect the compliance certificate within a month of completion, and chase the scheme operator if nothing arrives [9]. If the installer sits outside such a scheme, the council's building control approves the work instead, and its completion certificate is worth holding the final payment for [10].
Pricing
As of autumn 2026, rough Telford ranges run like this: a like-for-like combi swap £1,800–£3,500; a premium combi swap £3,000–£4,500; a system boiler replacement £1,800–£3,500; and converting a regular or system boiler to a combi £3,000–£5,700 [2]. These are guide prices including installation — your quote depends on your home, current system and boiler choice [2].
What moves the price is the work around the unit: relocating the boiler, changing boiler type, rerouting the flue, upgrading pipework, a powerflush at £300–£750, and controls such as a smart thermostat at £100–£250 [1]. Telford usually sits below London and South East prices for equivalent work [1].
Get an itemised quote naming the boiler model and output, flue, filter, controls, flush type, making-good, removal, VAT, and both completion documents — the Benchmark certificate and the Building Regulations notification [4]. Never accept a lump sum with no breakdown; ask which lines your home could drop and what would add a return visit.
Check whether each figure includes VAT before you compare, since guides and quotes do not always treat it the same way. If a firm offers monthly payments, get the term, the total payable and who provides the credit in writing — a low monthly figure can hide a long commitment. Fix the full fitted total, the payment stages and what changes the price if the engineer finds worse pipework than expected, all before you agree anything.
Each installation type has its own pressure points. A like-for-like combi swap stays at the bottom of the range when the flue, gas run and controls can stay where they are; a system boiler replacement climbs once cylinders, tanks or ageing pipework join the scope; conversions climb furthest, with back-boiler removal, new flue routes and making-good each adding labour days [2]. Across two thousand quotes generated in the first half of 2026, the median quoted price for a standard combi replacement was £2,300, with most straightforward swaps quoted between £2,150 and £3,000 depending on model, warranty and controls [2].
The smaller jobs carry smaller ranges. As of summer 2026, a one-off annual boiler service costs £70–£120, with older boilers, unusual makes and hard-to-reach positions landing at the top end; a landlord gas safety check for one appliance runs £60–£90, averaging around £80, with roughly £10–£15 per extra appliance; booking the service and the check together typically lands at £100–£150 [12] [15]. What moves these prices is the appliance count, the boiler's age and position, and whether the visit is bundled, since a lone check costs more per visit than one folded into a service [12] [15].
Red flags
Quotes a replacement without visiting, measuring up or asking about bathrooms, radiators and insulation.
Cannot show a current Gas Safe ID card or dodges checking the number on the register [3].
Prices with no system clean and no filter, and cannot explain what that means for the warranty [1].
Asks for full payment before the boiler is commissioned, with no written terms [6].
Promises the Benchmark certificate and Building Regulations notification but names neither and files nothing [4].
Names a boiler maker as an accreditation but shows no paperwork tying the longer warranty to your installation.
Will not put the boiler model, scope and price in writing before taking a deposit.
Offers monthly payments without naming the term, the total payable and who provides the credit.
Starts work with no agreed dates and no written scope, then prices each extra as it appears.
Corrections and business responses
Tell us what needs checking, or ask to claim a listing and reply to an assessment.