Buying Guide for Water Heater
- Common Size / Rating
- Rating:
Storage type: about 1.5kW to 18kW
Instantaneous type: about 6kW to 27kW
- Capacity: Storage type: from 8 litres to 300 litres or above
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Selection of Water Heater
Storage type Water Heater
- According to the storage capacity and the way of mounting, electric storage water heater can be classified as follows:
- Small-size unvented domestic electric storage water heater with a rated capacity not exceeding 50 litres
- Small-size open outlet domestic electric storage water heater with a rated capacity not exceeding 50 litres
- Horizontal tank type domestic electric storage water heater with a rated capacity exceeding 50 litres and up to 300 litres
- Vertical tank type domestic electric storage water heater with a rated capacity exceeding 50 litres and up to 300 litres
- Storage type water heater heats the water in the tank constantly but there is energy loss for standby heating.
- A larger size may be necessary for simultaneous usage of hot water for bathtub and shower in your bathroom and wash basin in your kitchen.
- We advise you to pay particular attention to the insulation for your hot water system because better insulation can help reducing heat loss significantly.
Instantaneous type Water Heater
- Instantaneous type water heater can provide on-demand hot water without continually storing and constantly heating water. There will not be any energy loss for standby.
- Instantaneous type water heater is activated by water flow. It uses thermostatic control for suitable outlet water temperature. You have to ensure that your water pipe system has sufficient water pressure for operation.
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A 6kW single-phase instantaneous type water heater is suitable for hand washing and kitchen basin. For a hot water bathtub, you may need higher wattage, say, a 18kW 3-phase water heater, to meet the hot water demand.
- The Energy Efficiency Labelling Scheme for electrically operated storage water heater with a storage capacity not exceeding 300 litres for domestic use adopts the "Grading Type" Energy Label. The energy consumption due to standby loss of a Grade 1 water heater is about 25% less than that of "average" Grade 3 product. Try to choose a water heater with an energy label to save energy.
- It is necessary to install a switch with appropriate rating to cut off the electricity supply to all conductors of the water heater. If your water heater is installed inside the bathroom, the switch should be installed beside the door outside the bathroom.
- Some shower type water heaters must only be fitted with an unblocked open-outlet type water mixer and shower accessories including flexible hose and showerhead.
- For other energy efficient tips and safety precautions, please refer to our website "Efficient Use of Electricity|Efficient Use of Electricity" and "Safety Tips on Using Electricity|Safety Tips on Using Electricity" respectively.
- For other information on electric water heaters, please refer to our website "Electric Living".