Why Heat Pumps Need a Cylinder
Heat pumps work best heating water slowly to a stored cylinder, allowing operation at lower temperatures for longer periods — maximising efficiency. A cylinder also provides a buffer to meet peak hot water demand.
Cylinder Size Guide
- 1–2 person: 150–180 litres
- 3–4 person: 200–250 litres
- 5+ person: 250–300+ litres
Dedicated Heat Pump Cylinder
Purpose-designed with a large internal coil (typically 2.5–3.0m²) to maximise heat transfer at low flow temperatures. Required for efficient heat pump operation.
Legionella Prevention
A weekly anti-legionella cycle using the immersion heater brings cylinder temperature above 60°C. Set up during commissioning and runs automatically.
Sources: MCS and Vaillant UK.
