A water heater is rarely replaced by choice. It leaks on a Sunday, it only half heats, or an inspection reveals a tank eaten away by limescale. The temptation is to order the same model and have it fitted the same day. Between Geneva and Lausanne, however, that reflex is no longer always possible, nor always wise: cantonal rules have changed, and the classic electric boiler is now the most expensive option to run.

Signs that a water heater is reaching the end of its life

A well-maintained boiler usually lasts fifteen to twenty years. In hard water, as across much of the Geneva basin, it can wear out noticeably faster. The warning signs are always the same.

  • Water at the foot of the tank, even a little: an enamelled tank that weeps cannot be repaired.
  • Hot water running out sooner than before, a sign that scale fills part of the volume or coats the element.
  • Crackling noises while heating, typical of a thick layer of limescale at the bottom.
  • Lukewarm, rusty or bad-smelling water at the first draw of the morning.
  • A protective anode that has never been checked on a unit more than ten years old.

One sign alone does not condemn the unit. Two or three at once, on a boiler approaching fifteen years, justify planning the replacement before the breakdown rather than after it.

Electric, heat pump or connected to the heating

There are three families of solutions for a home. They do not cost the same to buy, and even less to run.

The classic electric boiler

An element heats the water, preferably at night. The unit is simple, compact and cheap to buy. It is also the most energy-hungry: every kilowatt-hour of hot water costs a kilowatt-hour of electricity. For a household of four, hot water alone can account for a quarter of the home's electricity bill.

The heat pump water heater

A small built-in heat pump draws heat from the surrounding air and transfers it to the water. For the same hot water, it uses roughly two to three times less electricity than an element. In return, the unit is taller and more expensive, it makes a slight fan noise and it cools the room it stands in. It also needs a drain for condensate.

Hot water from the heating system or solar

When the house is heated by a heat pump, a district heating network or a boiler, hot water can be prepared by the same system, with a storage tank connected to the heating circuit. Solar thermal collectors can cover a large share of summer needs. In an apartment building, it is usually the co-ownership that decides, not the occupant of one flat.

What the rules say in Geneva and the canton of Vaud

The French-speaking cantons each apply, in their own way, the cantons' model energy regulations (MoPEC). Its principle is simple: in a dwelling, a direct electric water heater should no longer be installed or replaced as is, unless the water is preheated by the heating during the cold season or produced at least 50 % from renewable energy.

The canton of Vaud has gone further. The decree on the remediation of electric heating and water heaters came into force on 1 January 2025: electric water heaters, centralised or not, must be replaced by 1 January 2033 with a mainly renewable solution. Extensions or exemptions exist depending on the building's energy class, and for decentralised water heaters, offsetting with simultaneous solar production is possible.

In Geneva, the energy law and its regulation have steered all heat production towards renewables since the 2022 revision. In practice, before replacing an electric boiler with an identical unit, you need to check what the building allows and whether a step with the cantonal energy office is required. It is a few minutes of checking up front, and a surprise worth several thousand francs if it is forgotten.

Sizing the volume correctly

A boiler that is too small has to heat during the day at the full tariff; one that is too large stores hot water for nothing and loses heat constantly. The calculation starts from the number of occupants and their habits, not from the size of the old unit.

  • One to two people: 150 to 200 litres.
  • Three to four people: 250 to 300 litres.
  • Five people or a large bathtub: 300 to 400 litres.

For a heat pump water heater, aim for the upper end of the range, because it reheats water more slowly than an element.

Location, the question people forget

An electric boiler fits almost anywhere. A heat pump water heater does not. It needs a room of sufficient volume, usually around twenty cubic metres, or a connection to air ducts. A cellar or laundry room works well, and it dehumidifies them as a bonus. A cupboard in a flat rarely does.

You also need to check the ceiling height, whether the floor can carry more than 400 kilos once the tank is full, a drain nearby and the distance to the taps. The longer the pipe, the longer you wait for hot water at the tap.

Legionella: the temperature is not negotiable

To save money, it is tempting to lower the boiler setting to 50 °C. It is a false economy. Legionella bacteria multiply in stagnant water between 25 and 45 °C, and federal recommendations call for water at 60 °C in the heater and at least 55 °C in the distribution. A correctly set heat pump water heater reaches that level, with an electric boost scheduled once a week if needed.

How much a replacement costs

The amounts below are orders of magnitude for one dwelling, including installation and connections, excluding unforeseen work.

  • Electric boiler of 200 to 300 litres, like-for-like replacement where it is allowed: about 2,500 to 4,500 francs.
  • Heat pump water heater of 250 to 300 litres: about 5,000 to 9,000 francs depending on location and the adaptations required.
  • Storage tank connected to the existing heating: highly variable, depending on the heat source and the distance.

The difference at purchase is recovered in use: a heat pump water heater commonly saves a family several hundred francs of electricity a year. Cantonal and municipal programmes support these replacements; the application is filed before ordering the equipment, never after.

How a replacement is carried out

Once the choice is made, the work itself is short.

  1. Technical visit: volume, location, condition of the pipes, power supply and applicable rules.
  2. Detailed quote and, if needed, the subsidy application or administrative step.
  3. Draining and removal of the old unit, taken to a recycling channel.
  4. Installation of the new unit, a new safety group, plumbing and electrical connections.
  5. Commissioning, temperature setting and an explanation of how it works.

For a simple replacement, hot water is back the same day. For a switch to a heat pump, allow one to two days depending on the adaptations.

How SmartHaus Swiss handles it

A water heater involves both plumbing and electrics, and that is exactly where replacements get complicated: a line to redo, an undersized breaker, a missing drain. Our teams combine both trades, so there is no waiting for a second contractor. We first check what the canton requires for your building, propose the solution that makes sense over twenty years, and prepare the subsidy application when one exists.

Frequently asked questions

Can an electric boiler still be replaced with an identical model?

It depends on the canton and the building. In the canton of Vaud, electric water heaters must disappear by 2033, with exceptions. In Geneva, the legislation favours renewables. Checking before ordering avoids fitting a unit that will have to be changed again.

How long does a water heater last?

Usually fifteen to twenty years. In very hard water and without regular descaling, its life can drop to around ten years.

Does a heat pump water heater work in a flat?

Rarely in a cupboard, because it needs enough air volume or ducts. A cellar, a laundry room or a plant room is far better suited.

Do you need an electrician to change a boiler?

Yes. The electrical connection of a water heater must be done by an authorised professional, and the existing line must be checked. Our teams handle the plumbing and the electrics in the same visit.

Are there subsidies for a heat pump water heater?

Yes, depending on the canton and sometimes the municipality. The rule is always the same: the application is filed and approved before the equipment is ordered.