Control of DHW storage charging (with direct electric heating or integrated electric heat pump)

What does this smart-ready service measure?

This service, designated DHW-1a, assesses how intelligently a building manages the charging of domestic hot water storage. It covers storage with direct electric heating or an integrated electric heat pump.

The service falls under the Domestic hot water domain, one of nine domains within the Smart Readiness Indicator (SRI). The SRI is a European methodology that measures how well technical systems in a building communicate with each other and adapt to user needs and electricity grid requirements.

This service is part of Method A, the simpler of two calculation methods within the SRI. Method A uses 27 of the 54 smart-ready services in total.

What levels are there?

The service has three functionality levels, numbered 0 to 2. Each higher level adds control that helps the system better align with energy demand and supply.

• Level 0: automatic on-off control, without further management.
• Level 1: automatic on-off control with time-based charge release, so charging occurs at fixed times.
• Level 2: automatic on-off control, time-based charge release and additionally demand-driven supply temperature regulation or multi-sensor storage management.

A higher level means more options to align the charging time with periods of low energy prices or high renewable generation.

How does this count toward the SRI score?

Each smart-ready service is assessed against seven impact criteria, such as energy savings and comfort. These criteria are grouped into three key functionalities that carry equal weight.

The outcome of all services combined leads to an overall score in percentage points, divided into seven classes. The highest class ranges from 90 to 100 percent, the lowest falls below 20 percent.