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Swap your boiler like-for-like.
Same brand or any brand, same position — no system change, just a clean modern replacement.
✓ Updated May 2026✓ Free quotes✓ Vetted pros
20,000+UK homeowners
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Hire a boiler engineer. Without the warranty void.
You've read the brief on like-for-Like Boiler Swap. Now lean on us to find the right boiler engineer — and stay in control of the job.
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02 · Read the brief
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Costs, timelines, pitfalls and the right questions to ask before any boiler engineer starts on like-for-Like Boiler Swap.
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Itemised quotes from up to 3 local boiler engineers on like-for-Like Boiler Swap — so you can compare like-for-like, not lump sums.
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Top tips
Hiring a boiler engineer, without the regret.
Four moves that separate a smooth job from a nightmare.
Hidden discoveries
— old gas supply needs upgrading.
System contamination
— power flush may reveal damaged radiators.
Skipping power flush
— voids warranty + harms new boiler.
Costs & timeline
Know what it costs. Know when it ends.
Indicative UK ranges and what affects price.
Cost range
By job type
Inc. VAT · 2026
Source: NMT quotes
Source: NMT quotes
Budget combi (Ideal Logic, Baxi 600)5-7 year warranty
£1.8k–£2.4k
Mid combi (Worcester CDi, Vaillant ecoTEC)10 year accredited warranty
£2.4k–£3.2k
Premium combi (Worcester 8000, Viessmann)10 year + premium build
£3k–£4.5k
System boiler swapReusing cylinder
£2.2k–£4k
!
Quote spread is typically ± 18% — always get 3 quotes.
At a glance
Infographic · VideoThe Boiler Engineer briefing.
Infographic
Boiler Engineer quick-view
Video guide
Boiler Engineer explained
The most common UK boiler installation is a like-for-like swap — same location, same type (combi for combi, system for system), updated to a modern A-rated unit. It's the cheapest and fastest replacement option. This guide covers what it costs in 2026, what's actually involved, and how to verify the quote.
What Does the Work Involve?
- Survey to confirm like-for-like is possible.
- Power flush existing system.
- Remove old boiler.
- Install new boiler in same location.
- Connect to existing gas, water, electrical.
- Replace flue if needed.
- Test and commission.
- Building Control + warranty registration.
Typical Costs
| Boiler tier | Low £ | High £ | Notes |
|---|---|---|---|
| Budget combi (Ideal Logic, Baxi 600) | 1,800 | 2,400 | 5-7 year warranty |
| Mid combi (Worcester CDi, Vaillant ecoTEC) | 2,400 | 3,200 | 10 year accredited warranty |
| Premium combi (Worcester 8000, Viessmann) | 3,000 | 4,500 | 10 year + premium build |
| System boiler swap | 2,200 | 4,000 | Reusing cylinder |
How Long Does It Take?
- Single day for most like-for-like swaps.
- Plus survey + scheduling time before.
UK Regulations
- Gas Safe + Building Control standard.
- Boiler Plus controls required.
Common Problems
- Hidden discoveries — old gas supply needs upgrading.
- System contamination — power flush may reveal damaged radiators.
- Skipping power flush — voids warranty + harms new boiler.
Frequently Asked Questions
Is a like-for-like swap always possible?
Usually yes if site is in good condition. Major changes (gas supply upgrade, flue rerouting) bump cost.
Should I get the cheapest boiler?
Mid-range is usually best value. 10-year warranty on premium boilers often saves money over lifetime.
What's included in install?
Boiler, install labour, magnetic filter, flue, controls, commissioning, paperwork. Confirm in writing.
Power flush always needed?
Strongly recommended. Without, new boiler warranty may be voided by manufacturer.
How much can I save?
30-50% efficiency improvement over 10+ year old boilers. £200-£400/year saving typical.
Do I need new radiators too?
Usually no. Old radiators continue working. Replace individual ones that are corroded or leaking.
This guide was written with AI assistance and is intended for general information only. Prices are estimates based on UK averages and may vary by region. Always get at least three quotes and consult a qualified professional before starting any work.
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