Eco Cistem holds 18 litres, which is three times more than a conventional cistern so it would give four flushes to a 4.5 litre toilet.

The flush volume can be simply adjusted at installation stage in 0.5 increments to give varying flushes ranging from a 6 litres maximum down to 3.5 litres.

The upper chamber is continually topped up with condensate ensuring an on-going supply.

It means that in hot climates where a huge amount of condensate is generated, mains water should never have to be used.