Heat, Power & the Water Equation

Ama’s shower runs from a combi boiler. In August it’s strong; in January it’s noticeably weaker, though it’s just as hot. Same boiler, same shower, same setting, and nothing in the house has changed. Her shower is thermostatic: it holds the water at the temperature she has set.

The explanation is the same idea that runs every radiator in her home. A heating system is a chain for moving heat. The boiler’s flame heats water; the water carries that heat along the pipes; a radiator hands it to the room; and the room loses it through its walls, windows and draughts. Water is the delivery van, and this lesson is about how much heat each litre can carry.