The number of bathrooms is only a starting point. Two showers used together place a different demand on the system from bathrooms used one after another.
We consider simultaneous use, outlet requirements, available storage space, cylinder recovery and the incoming water supply. Where stored hot water is appropriate, capacity and recovery need to suit the household rather than follow a generic house-size rule.
An unvented cylinder does not cure a restricted incoming supply. Pressure and flow should be assessed under relevant demand before promising improved performance. If supply limitations require separate attention, our guide to home water-pressure boosters explains the options.
We also distinguish domestic water pressure from the pressure within the sealed heating circuit. They are separate parts of the installation.
For projects replacing older stored-water arrangements, see our vented-to-unvented conversion guide.
Keeping an existing cylinder or specifying a new one also means planning for maintenance. See our guide to servicing an unvented cylinder for the checks and access considerations that continue after installation.
If the project includes a new vessel or a change in hot-water storage, our cylinder installation and replacement in Queen’s Park service sets out the assessment, associated work and handover.
For projects also changing domestic water delivery, our water-pressure boosting for Queen’s Park homes can be planned with the storage, plant space and electrical supplies. This is separate from maintaining pressure in the sealed central-heating circuit.