Water-based thermal mass (drum / water wall)

Water-filled containers as thermal mass; higher heat capacity per volume than masonry, but needs a sealed, leak-proof enclosure.

Cost

Low

Upkeep

Occasional

Skill to build

Basic

Lifespan

20-30 years for the containment (drums/tanks) before corrosion or UV degradation of plastic components; water itself doesn't wear out

Embodied carbon

Low

Space / material use

High

Output timing

Continuous process

Skill to repair

Basic

Note: Cost, carbon and footprint are rated against the other options for this same need, not in absolute terms.

What your site needs

A sealed, leak-proof, structurally adequate location (water thermal mass is heavy)

Inputs

• Heat

Outputs

• Heat

Sources

• General water-wall/thermal-mass container industry durability consensus

What this page does not tell you

No sizing or quantities: how much a technique yields, and how much a household needs, both depend on the build and the people, so the catalogue compares options rather than dimensioning them. It carries no bill of materials and no build sequence, and it is written for an oceanic, clay-soil climate (Normandy, France). Regulatory notes are indicative and need confirming locally.