Short answer
A combi boiler suits most homes with one bathroom and steady mains pressure: it heats water on demand, needs no cylinder and frees up space. A system boiler with a hot water cylinder suits homes with two or more bathrooms in use at once, weaker mains flow, or plans for solar or a heat pump later.
How to decide
- How many showers run at once? A combi serves one outlet well. Two showers at the same time usually point to a system boiler and cylinder.
- What is your mains flow like? A combi can only deliver what the incoming main supplies. We measure flow and pressure on the survey.
- Do you need the space? A combi removes the cylinder and loft tanks.
- Future plans? A cylinder can later take solar thermal or a heat pump.
For the full comparison, read our combi vs system boiler guide and how to choose the right boiler. We fit Baxi, Worcester Bosch, Ideal and Viessmann boilers. New boilers start from £1,750 inc VAT, subject to a site inspection: see new boilers in Telford and boiler installation costs.
Related questions
Combi or system boiler?
A combi boiler suits most homes with one bathroom and steady mains pressure: it heats water on demand, needs no cylinder and frees up space. A system boiler with a hot water cylinder suits homes with two or more bathrooms in use at once, weaker mains flow, or plans for solar or a heat pump later.
Can I swap a system boiler for a combi?
Often, yes. Swapping to a combi removes the hot water cylinder and any loft tanks, which frees up space. It only works well if your mains water flow and pressure are good enough and you rarely need two showers at once. We measure the flow and check the pipework before recommending it.
Is a combi boiler cheaper to run than a system boiler?
Running costs depend more on the boiler being correctly sized, set up and controlled than on the type. A combi avoids heating and storing a cylinder of water you may not use, while a system boiler can suit bigger households. We set flow temperatures and controls on every installation we commission.
How much does a new combi or system boiler cost?
CombiCert new boilers start from £1,750 inc VAT, supplied and fitted. The final price depends on the boiler, any change of type or position, flue route and system condition, so every price is subject to a site inspection. We explain each item on the quote before you decide.
Want an engineer to look at it?
Call or WhatsApp 07393 220694, Monday to Saturday, 08:00 to 19:45. CombiCert Ltd is Gas Safe registered (621146) and based in Telford, Shropshire.