Combi, system or regular: choosing for a Teesside home
One bathroom and decent mains flow points to a combi. Two bathrooms used at the same time, or a modest flow rate, points to a system boiler with a cylinder. Regular boilers still suit older gravity-fed properties.
The three boiler types do the same job in different ways, and choosing badly is expensive in daily annoyance rather than in money. Here is how the decision actually falls in Teesside housing.
Combi boilers
A combi heats water as it flows, so there is no cylinder and no loft tanks. It suits the majority of Teesside terraces, flats and two- or three-bedroom semis with one bathroom. Benefits: space, simplicity, no stored water going cold and no waiting. Limits: it can only heat what the mains delivers, so two outlets at once means both suffer, and a bath fills at whatever rate the street supplies.
System boilers
A system boiler works with a sealed, pressurised cylinder, usually unvented. Several outlets can run at once at good pressure, which is why it is the right answer for houses with two or more bathrooms and busy mornings. It needs a cupboard for the cylinder and an annual check on the unvented components, and it costs more to install, typically £3,200 to £5,000 with a new cylinder.
Regular, or heat-only, boilers
The traditional setup: boiler, cylinder, and feed and expansion tanks in the loft. Still sensible in older properties with fragile pipework where converting to sealed pressure risks finding every weak joint at once, and in homes where the existing gravity layout works well. Replacement is straightforward and cheaper than converting.
Flow rate settles most arguments
Run the kitchen cold tap into a measuring jug for exactly ten seconds and multiply by six for litres per minute. Above 15 litres a minute, a combi has room to work. Between 12 and 15, a combi is workable in a one-bathroom house. Below 12, a combi will disappoint no matter which model is fitted, and stored hot water is the better route. That one measurement outranks every brochure claim.
Matching type to Teesside property
| Property | Usually best | Why |
|---|---|---|
| Two-bed terrace, one bathroom | Combi | Space saved, demand never overlaps |
| Three-bed semi, one bathroom and en suite | Combi or system | Depends on whether showers overlap |
| Four-bed detached, two-plus bathrooms | System and cylinder | Simultaneous demand at good pressure |
| Older property, gravity system, low flow | Regular | Keeps a working layout, avoids pressurising old pipework |
| Flat or apartment | Combi | No space for cylinder, single bathroom |
The mistake to avoid
Buying a bigger combi to solve a flow problem. Output in kilowatts governs how fast water is heated, not how much arrives, so a 38kW appliance on a 10 litre a minute supply delivers exactly as little as a 24kW one, while costing more and cycling harder on heating. Measure first, then choose.