Office · Domestic hot water
Domestic hot water in office: what the SRI measures
Domestic hot water covers the boiler or storage tank: is water heated on a fixed schedule or based on use, can the system use cheap electricity or solar heat, and is the circulation pump controlled smartly.
In short
- 1This page shows how the Smart Readiness Indicator, or SRI, addresses domestic hot water in offices.
- 2Domestic hot water counts as 1 of the 3 key functionalities in an office's SRI score.
- 3In many offices with large installations above 290 kW, building automation is already expected, and the SRI makes visible how intelligent that control is.
Weight of this domain for this building type
Which services count
| Service | Lowest level | Highest level | Advice |
|---|---|---|---|
| Control of DHW storage charging (with direct electric heating or integrated electric heat pump) DHW-1a · A · 3 levels | Automatic control on / off | Automatic on/off control, scheduled charging enable and demand-based supply temperature control or multi-sensor storage management | at least level 1 |
| Control of DHW storage charging DHW-1b · A · 3 levels | None | Automatic charging control based on local availability of renewables or information from electricity grid (DR, DSM) | at least level 1 |
| Control of DHW storage charging (with solar collector and supplementary heat generation) DHW-1d · 4 levels | Manual selected control of solar energy or heat generation | Automatic control of solar storage charge (Prio. 1) and supplementary storage charge, demand-oriented supply and return temperature control and multi-sensor storage management | – |
| Sequencing in case of different DHW generators DHW-2b · 5 levels | Priorities only based on running time | Control according to dynamic priority list (based on current AND predicted load, energy efficiency, carbon emissions, capacity of generators AND external signals from grid) | – |
| Report information regarding domestic hot water performance DHW-3 · A · 5 levels | None | Performance evaluation including forecasting and/or benchmarking; also including predictive management and fault detection | at least level 1 |
Worked example
If everything in this domain is at level 0, the domain contributes nothing. At the highest level for all services, the indicative total score for this building type rises by about 8 percentage points (from 31 to 39 percent, with all other domains at level 1).
Why does domestic hot water count in an office?
Offices use domestic hot water mainly for sanitary purposes: washbasins, kitchens and sometimes showers. Consumption is usually limited compared to heating, cooling and ventilation.
Yet this domain is included in the Smart Readiness Indicator (SRI) methodology and contributes to a building's overall score. For offices, the domestic hot water domain carries the weight of 1 of the 3 key functionalities, less heavy than heating or ventilation, but still significant.
Which smart-ready services are assessed?
The methodology evaluates five smart-ready services within this domain. Each service receives a functionality level, from 0 (no control) to higher levels with automatic and demand-driven regulation.
- Control of storage charging for electric heating or heat pump systems
- Automatic load management based on renewable energy or grid information
- Load control via solar energy with backup generation
- Scheduling priority among multiple hot water generators
- Performance reporting on domestic hot water
An office with only a time clock on the boiler scores at the lowest level on most of these services. An office with demand-driven control and performance monitoring scores significantly higher.
What does this mean in practice for an office?
Many offices already have a building management system (BMS), but that system is not always well tuned for domestic hot water. The boiler is then heated at a fixed time, regardless of actual occupancy.
Because offices have varying occupancy per day and per hour, demand-driven control can reduce waste. Think of a system that charges the hot water tank only when there is genuine demand or when cheap or renewable power is available.
How does this domain relate to the rest of the building?
Domestic hot water is not the largest energy item in an office. Lighting, ventilation and climate control typically weigh more heavily in the overall SRI score.
Yet a low level in domestic hot water can lower the overall score, especially if other domains already score well. For buildings above 290 kW, where building automation is often already in place, there is opportunity here that is straightforward to capture.
What this means for you
- Owner
- Have the existing hot water system control inspected, as a fixed time clock scores low while demand-driven control or coupling to solar energy can quickly raise the functionality level. This is relevant because the European Commission is expected to adopt a delegated act by 30 June 2027 at the latest that will make the SRI mandatory for utility buildings above 290 kW.
- Tenant
- As a tenant you notice little about this specific domain, except that hot water becomes available faster and less energy is wasted on unnecessary heating outside office hours.
- Advisor
- When assessing, verify whether the hot water storage is time-controlled only or also demand-controlled, and whether reporting functionality is present that enables forecasting or fault detection. Account for the relatively low weighting of this domain in offices, so that attention remains proportionate to its impact on the overall score.
Next step
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