Heating and Plumbing for a Granny Annexe
An annexe built for a relative or as separate living space usually needs its own independent heating and hot water rather than relying on the main house, particularly if it should keep working when the main house's system is off..
An annexe built for a relative or as separate living space usually needs its own independent heating and hot water rather than relying on the main house, particularly if it should keep working when the main house's system is off.
Independent versus shared systems
Some annexes tap into the main house's boiler and hot water; others get their own small system entirely so they're not affected by anything happening in the main house.
Separate metering considerations
If the annexe may ever be let separately or needs its own bills, a shared system complicates that in a way an independent boiler doesn't.
Accessibility-led plumbing choices
Annexes built for elderly relatives often prioritise level-access wet rooms and easily reached controls, which shapes the plumbing layout from the start.
Discuss your annexe's plumbing needs
Tell us who the annexe is for and whether independence from the main house matters, and we'll suggest the right setup.
Questions we get asked
Should an annexe have its own boiler?
Often yes, particularly if independence or future letting matters, but a shared system can work for close, permanent family use.
Can an annexe use the same water supply as the house?
Usually yes for a domestic annexe, though separate metering needs its own connection and paperwork if that's the goal.
Are wet rooms standard in annexes?
Common where accessibility is a priority, since they avoid step-over baths and shower trays, but not compulsory.