How we chose
We build the candidate list from the boiler installers Google Maps (Places) shows across Telford, then match each business at Companies House and read its own website for services, areas and terms. Claimed memberships are checked against the registers that matter for this trade — the Gas Safe Register for all gas work, plus TrustMark where it is claimed [3] [7]. Before we score anyone, we check that each business is who it says it is, is trading today and can actually be reached. We then score every eligible business against our scoring system, which looks at the things you care about when hiring: what customers say, the qualifications and registrations that matter for this trade, how the business responded when we contacted it, how long it has traded, insurance and safeguards, how clearly it prices, and how useful its website is. Anything we cannot verify stays neutral rather than counting against a business. The ranking shows its evidence date so you can see how fresh every check is.
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].
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].
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.
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.
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].
Corrections and business responses
Tell us what needs checking, or ask to claim a listing and reply to an assessment.