A household hot water heating system includes a cold-water inlet, a water heater or heat source, operating controls, safety and pressure-control valves, and insulated hot-water pipes supplying taps and appliances. A storage tank is not always included: continuous-flow systems heat water on demand.
Core components
- Cold-water inlet: Supplies water to the heater, often through isolation, non-return or pressure-control fittings.
- Water heater or heat source: Uses an energy source such as electricity, gas, ambient air or solar energy. The heating equipment may be an element, burner and heat exchanger, heat-pump circuit or solar collector.
- Operating controls: Storage systems commonly use a thermostat. Continuous-flow units use flow sensors and electronic controls to activate heating when water is drawn.
- Hot-water pipework: Carries heated water to taps, showers and connected appliances. Insulation reduces heat loss.
- Safety and pressure controls: Protect the heater and pipework from unsafe temperature or pressure. The required fittings vary by system design.
A temperature-and-pressure relief (TPR) valve releases water if temperature or pressure becomes excessive inside a storage water heater. A tempering valve instead mixes hot and cold water to limit the temperature delivered to designated outlets.
Do not cap, block or adjust safety-valve discharge pipes or temperature controls. If a valve needs attention, contact a licensed plumber.
Components by system type
| System type | Typical system-specific components |
|---|---|
| Storage | Insulated tank, heating element or gas burner, thermostat and TPR valve. Many tanks also have a sacrificial anode for corrosion protection. |
| Continuous flow | No bulk storage tank; typically includes a flow sensor, heat exchanger, gas burner or electric elements, and electronic controls. |
| Heat pump | Storage tank, evaporator, compressor, fan and condenser, arranged as an integrated or split system. |
| Solar | Solar collectors, storage tank, connecting pipework, controller and usually a gas or electric booster. Some systems also have a circulation pump or heat exchanger. |
Storage, heat-pump and most solar systems include a tank; a typical continuous-flow system does not. For advice on a suitable system and its required components, ask our Sydney installation team to assess your property and hot-water demand.