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Pausito · smart living

Water

Can I lower the water heater temperature to save energy?

Short answer

Better not: below 55 °C the legionella risk increases. Save on the amount of hot water instead, for example with shorter showers.

Legionella thermometer: Cold water below 25 °C (ideally below 20 °C), hot water at least 55 °C (ideally 60 °C); in between is the danger zone where legionella grows.
Legionella thermometer — Cold water below 25 °C (ideally below 20 °C), hot water at least 55 °C (ideally 60 °C); in between is the danger zone where legionella grows. (The text inside the figure is in Dutch.)

Explanation

In the EU hot water accounts for 15.6 % of household energy use. Still, health outweighs a few degrees here. Heat pump water heaters can often be set to heat up periodically; follow the manual and your installer.

Rules of thumb

  • Hot water: at least 55 °C, ideally 60 °C. [SW-S32]
  • Save with the shower head (≤ 7.2 l/min) and shorter showers (5 minutes). [SW-S41]

Pitfalls

  • A low water heater temperature plus little use (holiday home, second bathroom) is the riskiest combination. [SW-S32]

Search terms

These search terms are in Dutch; only terms that also find a topic in English are links.

boiler warmtepompboiler legionella energie

Read also

General information, not personal advice. Check the source and reference date.

For health complaints: see your GP.

Sources

  1. SW-S32 Legionella bij je thuis — Departement Zorg (Vlaanderen) (Reference date 2026-09-27)
  2. SW-S41 Besparen onder de douche en in bad — Milieu Centraal (Reference date 2026-09-27)
  3. SW-S43 Energy consumption in households — Eurostat Statistics Explained (Reference date 2026-09-27)

Reference date: 2026-09-27 · Translated with AI from the Dutch original.