Quick answer
A like-for-like combi swap in the same position is usually a one-day job. Moving the boiler, or converting a conventional system with tanks to a combi, normally takes two days. You will be without heating and hot water for most of the working day, and in almost every case we leave you with both working again before we go.
People rarely worry about the installation itself — they worry about the house being cold, the dog, the kids, and whether there will be a hole in the wall overnight. So here is what the day actually looks like.
Typical timings by job type
| Job | Typical duration |
|---|---|
| Combi to combi, same position | One day |
| Combi relocated to another wall or room | One to two days |
| Conventional system converted to a combi | Two days |
| System boiler with unvented cylinder | Two days, occasionally longer |
What happens on the day
- 1We arrive, lay dust sheets and protect the working area and your flooring.
- 2The system is isolated, drained and the old appliance removed.
- 3Pipework is adapted or renewed, and the gas supply is checked and upgraded if it needs it.
- 4The new boiler and flue are fitted and the system is cleaned and dosed with inhibitor.
- 5A magnetic filter is fitted where the installation includes one.
- 6The boiler is commissioned, gas rate and combustion checked, and controls set up.
- 7We run the heating and hot water, walk you through the controls and hand over the paperwork.
How long will you be without heating?
Expect no heating or hot water from roughly mid-morning until commissioning is finished. On a two-day job we will normally leave you with hot water overnight where the system allows it; if that is not possible we will tell you in advance rather than on the day.
What you get at the end
- Gas Safe registered commissioning and Building Regulations notification
- The manufacturer warranty registered in your name
- Benchmark commissioning record completed
- A walkthrough of the controls before we leave
Most installations booked within 24–48 hours
Get a fixed price for your installation and pick a date that suits you.
Get my fixed boiler quoteWhen to call a professional
Safe homeowner checks stop at pressure gauges, radiator valves, controls and visible pipework. Anything involving gas, combustion, the boiler casing, the flue or internal components is work for a Gas Safe registered engineer. If you smell gas, follow the appropriate emergency gas safety guidance and do not attempt to work on the appliance.
Call 07881 963508The Betaflo recommendation
A realistic timeline for a boiler swap or system conversion, and what actually happens hour by hour on installation day. If you'd like a second opinion before spending money, speak to us first — we'd rather tell you your boiler is fine than sell you something you don't need.
Frequently asked questions
Do I need to be home all day?
Someone over 18 needs to be in the property, but you don't need to watch the whole job. We'll need you at handover so we can run through the controls.
Will there be mess?
Draining a heating system means dirty water, so we sheet up and protect floors. Removing a cylinder or tanks creates more disruption than a straight swap.
Can the boiler go somewhere different?
Usually yes, within the limits of flue positioning, gas supply and condensate drainage. It adds time and cost, so we'll discuss it at quote stage.
About the author
Betaflo Heating UK
Betaflo Heating UK is founded and run by Miles Davis and Sam Boyle, Gas Safe registered heating professionals installing, servicing and repairing boilers across Tamworth, Birmingham and the surrounding areas. Our guides are written from the work we do in customers' homes every week. More about Betaflo.
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