Electric water heater: 50 litres is enough for two people

Electric water heater: how many litres a home needs and what to check before buying

Two people, hot water only for showers and a gas boiler that fires up five times a year for heating. With those premises, the bimonthly bill comes to around 40 euros, and most of it goes on the fixed charge and taxes, not on gas burned. The question that opens the topic is not how much the water heater costs, but how many litres you actually need so the tap doesn't run cold halfway through a shower.

The short answer that comes out of the accumulated experience: between 30 and 50 litres is plenty for two adults who don't shower at the same time. The 30-litre one means waiting about 15 minutes between showers if the first one runs long; the 50-litre one eliminates that wait and the price difference is negligible. Going up to 80 or 100 litres only makes sense if someone takes baths or wants the water very hot.

How many litres does an electric water heater need for a two-person household?

The consensus is broad: 50 litres is the safe bet. Those who have tried both sizes say the 30-litre one works if shower schedules don't overlap, because it recovers its temperature in half an hour. Those who live with more people and rely on 50 litres say they've never run out of water with three showers in a row within an hour.

The important nuance is usage. If you wash dishes with hot tap water, neither 30 nor 50 nor 80 litres will hold up: kitchen water drains the tank. And if someone takes baths, 50 litres won't fill the tub. For showers and little else, 50 litres are more than enough.

Is an electric water heater or a butane bottle cheaper?

Here the analysis splits. Some calculate that a bottle lasts four months and costs 16 euros, an unbeatable cost. But switching requires adapting the boiler to butane or propane with a certified installer, keeping two bottles on hand so you don't run out of hot water, doing the annual inspection and accepting that regulations may tighten later. The alucinación to the petrol station for a refill isn't free in time either.

The electric water heater has its own hidden cost: the heating element gets coated in limescale, especially in hard-water areas, and needs more energy to heat the same amount. Annual cleaning is a must if you don't want to overpay on every shower.

Real consumption of a 50-litre electric water heater

The figures discussed are modest. A 15-day measurement on a 50-litre heater came to 16 kWh, just over 1 kWh a day, which works out at around 390-400 kWh a year. The gas boiler, on the other hand, uses about 0.04 euros a day of electricity just for being on, plus the gas and its fixed charges.

The full calculation, item by item across the fixed charge, meter rental, consumption and taxes, gives a floor of 0.42 euros a day that the water heater doesn't necessarily match. That's where the trap of the easy sum lies.

Which brands and what installation make sense

On brands, experience is mixed: some replaced three heating elements and ended up with a punctured tank, while others have gone more than five years without a problem with another maker. The repeated recommendation is to go to a neighbourhood installation company with certified staff, especially if gas is involved.

Installing an electric water heater yourself is simple if you know the basics: fittings, pipes and plugging it in. The critical step is purging the air by opening the hot-water tap while it fills, because a large air pocket can make the unit explode. And a thermostatic valve on the outlet stretches the hot water further than it seems.

The adjustment almost nobody makes

Turning down the internal thermostat cuts consumption noticeably and, as a bonus, encourages quicker showers. The saving is double: less energy to keep the tank hot and less time under the stream. With the water at 42 degrees, as the boiler was set, the shower is more than fine.

That's where the comparison stalls. The water heater wins on simplicity and eliminating fixed charges, but loses on recovery and maintenance. The butane bottle wins on cost per litre heated, but loses on legality and logistics. Nobody has settled the account with all the factors included.