Unvented Cylinder or Combi Boiler? Choosing for a Cardiff Home

There's no universally best system. There's the right one for your house, your water supply and how many people shower at 7:30am.

Go combi if... You have one bathroom, limited space, and a decent mains flow rate (roughly 12+ litres per minute). Instant hot water, no tanks, no cylinder, more cupboard space. Ideal for the majority of Cardiff terraces and flats.

Go system boiler with an unvented cylinder if... You have two or more bathrooms, or several people needing hot water simultaneously. An unvented cylinder gives mains-pressure hot water to every outlet at once — a combi simply can't feed two showers properly.

The flow rate test decides it We measure your incoming flow before recommending anything. Fitting a large combi to a poor supply produces a disappointing shower and an unhappy customer, no matter how good the boiler is.

Space and safety Unvented cylinders need space, a discharge route for the tundish pipework, and an engineer holding the specific unvented qualification. Annual servicing of the expansion vessel and safety valves is a requirement, not an optional extra.

Older Cardiff properties Converting from a vented gravity system frees the loft tank and airing cupboard, but check the loft insulation and pipework condition while everything is exposed — it's the cheapest time to put it right.

Unsure which suits your home? Call PHBLUE on 07545 125168 for straight advice, no sales pitch.