Sizing Your Water Heater

Water Heater Sizing for Singapore

Sizing Guide for Apartments

Measures total quantity of warm water flow time each heater produces in minutes. This is a guide for heaters below 100 lit, the maximum size for wall hung heaters.
  1. Shower flow rate 10lit/min
  2. Temperature 38-40ºC
Everyone’s shower timings are different
NEA estimates the average Singaporean’s shower time around to be around 3.5 minutes of running water time. Shower is off when soaping.
Sizing Guide by Number of Users
There are no hard and fast rules. These are based off choices made by most homeowners of apartments.
  • Hot water run time in (parenthesis)
  • Yellow highlights the most popular choice(s) for corresponding family size
Sizing Guide for Landed Houses
Heat pumps are the most popular choice among private and landed housing because of their larger family size. This sizing guide is for central heat pump water heaters.

Based on 3.5 min/shower

Electric and digital heater alternatives:
  • For individual electric/digital water heater sizing, send us your floor plans at
  • To find out more about using central water heaters vs. individual water heaters, read this guide.
Sizing Guide for Bathtubs
Bathtubs require more water. Here are the recommended sizes for one filled bathtub and a subsequent shower.


Amanda is an education specialist at AOS Bath. She enjoys building a trusted network by sharing knowledge. Making difficult concepts simple and engaging is rewarding, on both ends.