Instant vs Storage Water Heater: Which is Better for You?
The best water heater depends on the kind of shower you enjoy and what matters most to you. Strong water pressure, endless hot water, energy efficiency, or convenience.
Here we compare the differences between instant and storage water heaters so you can see at one glance which one suits your home and lifestyle.
Still not sure?
Take an easy 2-min Water Heater Quiz to find your heater. The final choice is always yours. There is no single "best" water heater, only one that is best for you.
What's The Difference: Instant, Tankless, and Storage?
We usually think of our heater choices as instant vs storage, but a third option, the Tankless Heater, has been gaining ground and sits between the two.
Instant heaters have no tank, and are fixed inside the shower area. It is small and easy to install. One unit serves one bathroom.
Storage heaters heat a tank of water in advance and holds it ready. One tank can serve 2 bathrooms. It has the strongest flow, great for a rain showers.
Tankless is a hybrid. Like instant, its tiny tank is low-maintenance. But unlike instant, it can serve 2 bathrooms, like a storage heater. Stiebel Eltron, the world's largest tankless heater supplier, is the brand most associated with introducing Tankless in Singapore.
Which Heater is Popular for BTO and HDB?
In Resale HDB where pipes are already exposed, all 3 types of heaters are fine.
For BTO, the choice is between tankless and storage, not instant. Why?
1. BTOs come with concealed pipes. Fixing an instant heater means running an exposed pipe to the shower point. We want to avoid that.
2. Between tankless and storage, you only need one unit to serve the whole house instead of one per bathroom like with instant. This keeps the master bathroom free and spacious.
How to choose between tankless and storage?
• Tankless is valued for its small sleek design: won't block lights or doors, important in tight BTO bath layouts.
• Storage is prized for performance: strongest, most consistent water pressure. This matters if you're getting a rain shower.
Which Heater Gives the Best Water Pressure?
Storage: a must for rain showers, bathtubs, or the need for concurrent showers. Storage tanks are pressurised. They deliver the strongest and most consistent water flow.
Tankless is fine as long as you are using a hand shower. Its flow rate is no match for storage's pressurised output, so a rain shower is off the table. As for concurrent showers, the odds of two people turning on the mixer at exactly the same moment are low, so this is rarely a real-world issue.
Instant sits at the bottom for pressure, at just 4–5 litres/min. This is not just a "no rain shower" limit. It means you can't even use a normal hand shower and get a decent flow. You must use the special shower head that comes packed in the box with the unit. This is designed to work at that lower flow rate.
Storage has the best pressure. Tankless is a workable middle ground for hand showers, and instant is the most limited of the three.
Which Heater is More Energy Saving?
With NEA's new tick system, storage sits at 1-tick while instant and tankless get 4-ticks. The ticks make it easy to assume storage burns 4x the energy through heat loss, but that is not accurate.
NEA's tick system measures both energy and water savings. Heaters with a low flow rate score better because they use less water per minute, not just less energy. Storage uses more energy than tankless, but nowhere near 4x.
To put it in $ terms: the difference between a 4-tick heater and 1-tick heater (storage) will cost you $0.33/day, not 4x the energy bill.
Which Heater Costs More to Maintain?
Here, instant and tankless both come out ahead of storage, because neither has a tank.
Storage heaters need a tank flush every 3 years to clear out sediment buildup. That upkeep is about $60/year.
Instant and tankless heaters are low upkeep. No flushing, fewer moving parts. They only cost $30/year to maintain.
Conclusion: Instant or Storage?
Go storage if performance matters most to you. A rain shower, a bathtub, or the convenience to run two showers at once. You pay slightly more, a fraction of a cent a day in energy.
Go instant if you are in a resale flat, and low upfront and running costs matter more than water pressure.
If neither fits perfectly, tankless is worth a look. It combines storage's ability to serve the whole unit, and instant's lower running cost.
There's no "better" choice between instant and storage. It all comes down to what you need.
