Which measure specifically stops convection in hot water delivery?

• A. Reduce standby losses with insulation of pipes and unit
• B. Heat trap install to stop convection
• C. Reduce length of hot water piping
• D. Install a drain water heat recovery system

Answer: (B)

Convection in hot water delivery is driven by buoyancy: hot water tends to rise in the hot line while cooler water sinks, creating a circulating loop even when no hot water is being drawn. A heat trap blocks this buoyant loop by adding a barrier or a bent path at the hot outlet (and sometimes the cold inlet), making it difficult for hot water to circulate back into the cold line. This directly targets and stops the unwanted convection, significantly cutting standby heat loss.

Insulating pipes and the unit reduces heat transfer to the surroundings but doesn’t stop the buoyant circulation. Shortening hot water piping reduces surface area and potential losses but doesn’t address the convection path. A drain water heat recovery system improves overall energy use by reclaiming heat from wastewater, not by preventing convection.