Typical install time
Supplied & fitted (2026)
Worcester Bosch Accredited
How long does a boiler installation take?
The honest answer is "it depends on the job", but most domestic UK installations fall into three predictable brackets:
- Combi-for-combi swap (same location): 1 day. New boiler on the existing wall, existing pipework flushed and reused where possible.
- Combi swap with pipework or location change: 1–2 days. Extra time for new gas run, condensate route or a magnetic filter upgrade.
- System-to-combi conversion: 2–3 days. Removing hot water cylinder and cold tank, capping feeds, running new mains and full system flush.
- Oil boiler replacement: 1–2 days. Similar to a gas swap plus OFTEC checks on the tank and fuel line.
How much does a new boiler cost in 2026?
Prices below are supplied and fitted, including a system flush, magnetic filter and up to a 10-year manufacturer guarantee where the boiler qualifies.
| Install type | Typical price | Time on site |
|---|---|---|
| Combi swap (like-for-like) | £1,950 – £2,800 | 1 day |
| Combi swap with pipework upgrade | £2,400 – £3,300 | 1–2 days |
| System boiler replacement | £2,600 – £3,600 | 1–2 days |
| System-to-combi conversion | £3,200 – £4,500 | 2–3 days |
| Oil boiler replacement | £3,400 – £5,200 | 1–2 days |
Prices vary with brand, output (kW) and site conditions. We give a fixed written quote after a free home survey.
What happens on the day?
- Arrival & walk-through — dust sheets down, existing system isolated, water and gas turned off.
- Remove old boiler — old unit disconnected and taken away for recycling.
- Fit new boiler & controls — new unit mounted, condensate and flue installed, smart thermostat wired if included.
- System flush & magnetic filter — power flush or chemical clean depending on system condition.
- Commissioning & handover — full commissioning to manufacturer spec, gas safety notification, benchmark and warranty paperwork.
Combi swap vs system conversion — which is right?
Combi swap
Best for 1–2 bathroom homes. Cheapest, fastest and frees up cupboard space. Hot water on demand, but pressure is shared between outlets.
System / regular replacement
Best for 3+ bathrooms or high simultaneous demand. Keeps the cylinder, better multi-outlet performance, more parts to maintain.
FAQs
- How long does it take to install a boiler?
- A like-for-like combi swap is a 1-day job. Location moves take 1–2 days, and full system-to-combi conversions run to 2–3 days.
- How much to install a boiler in 2026?
- Supplied and fitted, a combi typically costs £1,950–£3,600. System conversions and oil replacements run higher due to extra parts and labour.
- Will I have heating and hot water that night?
- For same-day swaps, yes — we commission and rebalance the system before we leave so you have heat and hot water that evening.
- Do you clear away the old boiler?
- Yes, we remove the old unit and any redundant tanks/pipework for recycling as part of the price.
- What guarantee comes with the new boiler?
- As a Worcester Bosch Accredited installer we can offer up to a 10-year manufacturer guarantee on qualifying installs, subject to annual servicing.
Get a fixed written quote
Serving Bath, Radstock, Wells, Midsomer Norton and the Chew Valley. Free home survey, no pressure.