Converting an older open-vent or cylinder system to a combi starts at £2,699 and normally takes two days. We remove the cylinder and tanks, re-run pipework, make good and rebalance the system — and if a combi is the wrong answer for your house, we will tell you at the survey.
What a conversion involves
A conversion means moving from an older system with a hot water cylinder and a tank in the loft over to a single combi. It costs more than a swap because we remove the cylinder and tanks, re-run pipework, make good, and rebalance the whole system. Budget two days.
For most three-bed houses across Birmingham it is the change that makes the biggest difference to running costs and loft space — no stored hot water going cold, no tanks overhead, one appliance doing everything on demand.
When a combi is the wrong answer
If you have two or more bathrooms and a household that showers at the same time, a combi is often the wrong answer — one appliance heating water on demand has limits that a cylinder does not. We would rather tell you that at the survey than fit the wrong boiler. If your house is in that category, say so when you book and we will talk it through properly before quoting anything.
Conversion pricing
Conversions start at £2,699, with the final figure depending on the boiler you choose and how much pipework has to move. The survey fixes the number in writing before you commit.
| Job | Warranty | Fitted price |
|---|---|---|
| Baxi / Main Eco Compact — combi swap | 5 yr | £1,999 |
| Worcester Greenstar 1000 — combi swap | 5 yr | £1,999 |
| Baxi 600 — combi swap | 7 yr | £2,199 |
| Worcester Greenstar 4000 — combi swap | 10 yr | £2,699 |
| Vaillant ecoTEC plus — combi swap | 10 yr | £2,699 |
| Worcester Greenstar 8000 — combi swap | 10 yr | £2,899 |
| Conversion to combi (from system or open vent) | — | from £2,699 |
Every price includes the boiler, horizontal flue, wireless thermostat, magnetic filter, system cleanse and inhibitor, Building Regulations notification, and removal of the old boiler. Same-position swaps. Estimates confirmed after a free survey.
Costs that are not in the headline price
We would rather flag these now than surprise you on the day. A gas supply pipe that is undersized for the new boiler's output, a flue that has to be re-routed, a fused spur that needs moving, a system so heavily sludged it needs a power flush before the warranty is valid, or condensate that has to be run to a soil stack — any of these add cost. A free survey catches all of them before you commit.