Floor-to-ceiling water curtain dividing the living room

A sectional with a low deep seat, made of modules you can rearrange. In an open living room the advantage is that it can be set up as a chaise facing either way depending on where the divider ends up, which a one-piece sofa can't do. In a dark tone choose a textured fabric over a flat one: on a flat dark surface every piece of lint and every seat mark shows.

Timber slats mounted on a felt backing, which decorates and absorbs reverberation at the same time. It isn't the same as a decorative slat panel: the felt does the work, and without it the slats only add relief. In a large living room with a polished floor and a hard ceiling it's one of the few finishes that improves how the room sounds without hanging anything obvious.

A humidity and temperature meter, desk or wall mounted. With a large fountain running daily it's the first thing to have, because humidity climbs gradually and isn't noticed until condensation appears on a window. Choose a model with max and min memory: what matters isn't the reading at one moment but how high it gets overnight with everything shut.

A condensing unit sized by litres per day and by the room's cubic metres. With a floor-to-ceiling water curtain it's the insurance that saves you choosing between the fountain and the floorboards. Choose one with a humidistat so it starts by itself above a threshold rather than running constantly, and check the noise figure: in a living room, a loud model ends up switched off and put away.

A narrow-necked clay urn, used empty as a scale piece beside a large panel. Indoors it wants to be sealed, or seal it yourself: porous clay standing on a damp trough weeps and leaves a ring on the coping stone. Two slightly different sizes work better than a matching pair, because an exact pair turns the arrangement into a symmetry it doesn't need here.