Instantaneous Electric Water Heaters

Instantaneous Electric Water Heater

Instantaneous Electric Water Heater (IEWH), also known as tank-less or demand-type water heater, is recognised by authorities in many countries as “Green” water heater. Singapore’s authorities have encouraged the use of IEWH in households to promote water and energy savings, a part that everybody should contribute to protect the mother earth. 

IEWH is divided into 2 categories, Single Point (also known as Open Outlet) and Multi-point (also known as Closed Outlet).

Single Point IEWH – as the name implies, it can only supply hot water to ONE point.  The outlet of the IEWH must remains open, i.e., it cannot be fixed to any faucet, and the water flow is controlled at the inlet of the IEWH. Single Point IEWH is used solely for showering and it is one of the most convenient and economical way of supplying hot water in shower. The diagram below shows typical way of Single Point IEWH installation.


Multi-point IEWH – IEWH under this category can supply hot water to more than one outlet and hot water is controlled at the outlets with mixer faucets. This is a central water heater and it is popularly replacing storage and gas water heaters. The diagram below shows typical way of Multi-point IEWH installation.