The right water heater is not the newer one. It is the one your plumbing and your fuse board can support.

Most disappointing replacements start the same way: someone buys the technology instead of matching the house. A cylinder is replaced by an on-demand unit, and the first cold morning reveals that the circuit, the flow rate or the water hardness was never checked.

Anlabeier, the instant electric water heater brand of Zhongshan Chongde Electric Co., Ltd., makes on-demand units only, so this comparison comes from a manufacturer with an interest in one side of it. The six differences below decide the answer, whichever side you end up on.

Space, and Where the Unit Actually Goes

• A storage cylinder needs a footprint: an airing cupboard, a utility corner, sometimes a loft with the floor strength to carry a full tank.
• An on-demand unit is wall-mounted and takes roughly the depth of a thick book, so the cupboard can become storage again.
• In a flat, that recovered space is often the real argument.

Recommendation: measure the cupboard and the wall before you compare anything else. Space decides more installations than efficiency does.

Waiting Time, and Where the Hot Water Starts

• A cylinder delivers hot water almost immediately; the water is already hot.
• An on-demand unit heats as water passes, so there is a short delay while the cold water in the pipe clears and the element reaches temperature.
• The delay is longer where pipe runs are long, and shorter when the unit sits close to the outlet — the logic behind point-of-use units.

Recommendation: put the unit near the outlet it serves, and the waiting-time argument mostly disappears.

Running Out of Hot Water

• A cylinder has a fixed volume. When it is used up, you wait for recovery, which is the classic third-shower problem in a family bathroom.
• An on-demand unit keeps heating while water flows, so the supply continues as long as the flow stays within the unit's rating.
• The catch is simultaneous demand: two showers at once on a small unit will each get less temperature rise than one.

Recommendation: count simultaneous showers, not bathrooms. That number chooses the technology more often than floor area does.

What It Costs to Run

Running cost is arithmetic, not a slogan, and the inputs are yours: rated power, hours of heating, and your own tariff.

• An on-demand unit heats only while water flows; a cylinder also keeps a tank hot between draws, which is a standing loss.
• A tankless unit can reduce standing losses, but a high-power unit used briefly is not automatically cheaper than a well-insulated cylinder.
• Anyone quoting a percentage saving without your tariff and your usage pattern is guessing.

Recommendation: do the sum with your own bill before you believe any running-cost claim, including a manufacturer's.

Installation Requirements

This is where most surprises live.

• An electric on-demand unit needs a dedicated circuit sized to its rating; 3.5 kW draws about 15 A at 230 V, and 12 kW needs a substantially larger supply.
• A storage cylinder needs its own circuit too, but usually a smaller one, plus floor space and structural allowance.
• Hard water affects both: scale on an element, sediment in a tank. The routine is set out in Hard Water and Your Tankless Water Heater: A Descaling Guide.
• Cold inlet water reduces the temperature rise at any given flow, which matters most in winter — see Tankless Water Heater in Winter: 5 Checks for Cold Days.
• Neither side is a DIY electrical job. Use a licensed electrician, and keep the certificate.

Recommendation: price the circuit work before the unit. The wiring is the part that cannot be argued with.

Failure, Maintenance and the Long Run

• A cylinder can leak, and a leak in a loft is a ceiling. It also needs its anode checked and sediment flushed.
• An on-demand unit has no stored water to leak in volume; its common issues are scale on the element and electrical faults.
• A single Anlabeier unit is cheap to swap; a failed cylinder is a plumber, a delivery and usually a day without hot water.

Recommendation: design for the repair, not for the brochure. Ask how the unit comes out before you ask how it goes in.

Side by Side

Electric Tankless Water Heater Pros and Cons, Stated Plainly

Pros: no stored volume, no standing loss, a small wall footprint, and supply that continues while flow stays within the rating.

Cons: a short wait at the tap, a dedicated circuit that older properties may not have, a temperature rise that falls as flow or cold-water severity increases, and scale that has to be managed in hard-water areas.

Which Home Should Pick Which

• Studio or one-bathroom flat: a point-of-use on-demand unit at the outlet, if the circuit allows it. Layout notes are in Under Sink Water Heater: What to Check Before You Buy.
• Family house with two or three bathrooms used at once: a larger on-demand unit sized for simultaneous flow, or a cylinder if the supply cannot be upgraded.
• Older property with a small consumer unit: check the supply first; a cylinder may be the honest answer. What the electrical side involves is covered in Tankless Water Heater Installation: DIY or Call a Pro?.
• Rental flat or a portfolio: the failure model matters more than the technology — see Water Heater for Rental Property: A Landlord's Buying Guide.

Why Anlabeier

Anlabeier is the instant electric water heater brand of Zhongshan Chongde Electric Co., Ltd., a manufacturer in Zhongshan, Guangdong that has built instant electric water heaters since 2010. The range runs from 3.5 kW single-outlet to 12 kW whole-home units, with stainless steel or cast aluminium elements, ELCB leakage protection, dry-heating cutoff, overheat protection and IPX4 casings. The company holds more than 120 patents, works to CE, CB, RoHS, ETL and ISO9001 standards, and tests units at incoming inspection, temperature-control, semi-finished, finished-product and packaging stages.

Conclusion

There is no winning technology here, only a fitting one. Measure the space, count simultaneous showers, check the circuit, and ask who repairs what. Anlabeier units from Zhongshan Chongde Electric Co., Ltd. cover 3.5 kW point-of-use to 12 kW whole-home.

FAQ

Does a tankless water heater run out of hot water?
Not in the way a cylinder does. It heats while water flows, so the limit is the unit's rated power against the flow and the incoming water temperature, not a stored volume.

How long does a tankless water heater take to deliver hot water?
It depends on the distance from the unit to the tap and the pipework, not the heater alone. Fitting the unit close to the outlet shortens the wait.

Is tankless better than a tank?
Better at space, standing loss and continuous supply within its rating; worse at first-hot-water delay, circuit demand and scale. The house decides, not the label.