The engine under the hill

How the heat travels

• The spring rises at 41 °C into the collector well, a stone shaft behind the boiler house.
• A gravity main carries it under the yard to the cascade, losing 2 °C on the walk.
• The Meridian branch is tempered down to 33 °C at the mixing vault, a 1926 stone chamber with three bronze slides.
• The boiler tops up only what the spring cannot: about 8 °C of lift on the coldest mornings.

The two boilers

Big Bertha, the 1926 original, runs October to March and is the loudest resident of the house. Little Ada, her 1968 successor, runs the warm months and the scrubbing Thursdays. The yard door carries two plaques: "Bertha runs the winter" and "Ada forgives the summer".

The 1968 restoration replaced the fuel but kept the stone flue, which means the house heats the same hillside the same way it always did, just with less smoke and fewer arguments.

Demonstration: the boilers, their names and every number on this page are invented.