No radiator under the window, gentle warmth rising from the floor, feet that are never cold: underfloor heating appeals to many homeowners. In Geneva and Lausanne it is back in the spotlight for a simple reason, the move away from oil and gas. A heat pump works better the cooler the water it has to produce, and no heat emitter is happy with water as cool as an underfloor system. This guide explains how it works, what is possible in a renovation, what the cantonal rules say and how much to budget.

How underfloor heating works

A hydronic underfloor system is a network of cross-linked polyethylene or multilayer pipes laid in loops or spirals beneath the floor covering. Warm water flows through them from a manifold, a small cabinet usually set in a cupboard or recess, which splits the flow between the loops of each room. The whole floor becomes one very large radiator.

That surface area is what makes the difference. A conventional radiator needs water at 55 or 70 °C to heat a room. Underfloor heating usually gets by with 28 to 35 °C on cold days. For a heat pump, every degree less in flow temperature improves efficiency: going from 55 to 35 °C can cut electricity use by a quarter to a third over the season.

Comfort is different too. Heat is radiated evenly, with no hot air pooling at the ceiling and no cold zone near the windows. Most people feel comfortable one or two degrees cooler than with radiators, which saves even more.

Hydronic or electric: the law has settled it

Electric underfloor heating also exists, with heating cables or films glued under the tiles. It is cheap to install and very thin, which makes it tempting in a renovation. In French-speaking Switzerland, however, it can no longer serve as the main heating.

  • In the canton of Vaud, article 30a of the energy law (LVLEne) sets the principle that installing or renewing resistive electric heating is prohibited. A 2022 decree goes further: existing electric heating must be replaced with a renewable system before 1 January 2033, with exemptions and subsidies provided for.
  • In Geneva, connecting fixed resistive electric heating to the grid requires authorisation from the cantonal department, granted only in exceptional cases.

In practice, underfloor heating installed today to heat a home is hydronic, supplied by a heat pump, a district heating network or the building's central heating. For a small electric comfort element in a bathroom, have your installer check the rules before you buy.

New build or renovation: three ways to install it

In a new building the question does not arise: the pipes are laid on insulation and embedded in a screed 6 to 8 centimetres thick. In a renovation, everything depends on the height available and the condition of the existing floor.

  1. Conventional screed: the covering and often the old screed are removed, insulation and pipes are laid, then a new cement or anhydrite screed is poured. This performs best but is also the heaviest option: allow 8 to 12 centimetres, significant weight and several weeks of drying before the covering goes down.
  2. Low-profile or dry system: grooved boards 2 to 4 centimetres thick hold small-diameter pipes and are covered with a thin screed or spreader plates. Ideal when the structure cannot be touched, at a higher cost per square metre.
  3. Milling: a machine cuts channels directly into the existing screed, the pipes are pressed in and covered with a levelling compound. You lose only a few millimetres of height and the job is quick, but the screed must be sound, thick enough and free of embedded pipes or cables.

Whatever the method, check three things before choosing: clearance under doors and at thresholds, the junction with stairs and neighbouring rooms, and the insulation beneath the floor. Without insulation, part of the heat goes to the neighbour below or to the cellar.

The floor covering matters as much as the pipes

Every covering slows the flow of heat. The European standard EN 1264, used in Switzerland, recommends a covering thermal resistance of no more than 0.15 m²K/W.

  • Tiles and natural stone are the best choices: they conduct heat very well.
  • Engineered parquet fully bonded to the screed works well, provided the manufacturer states it is compatible. Stable species such as oak cope with variations better than beech or maple.
  • Vinyl and linoleum are fine if they are certified for underfloor heating.
  • Thick carpet and solid wood floating on an insulating underlay should be avoided: they force a higher water temperature and the low-temperature advantage disappears.

For comfort and to protect coverings, the surface temperature is limited to around 29 °C in living areas. That is why underfloor heating assumes a reasonably well-insulated home: in a house with high heat losses, it cannot deliver enough heat without exceeding that limit.

In an apartment block or condominium

In Geneva and Lausanne many projects concern a flat. Three constraints then come into play.

  • Consent: as a tenant, nothing happens without written consent from the landlord or the property manager. In a condominium (PPE), work on screeds and the shared heating network usually needs the administrator's approval, sometimes a vote of the owners' meeting.
  • Acoustics: replacing a screed can worsen impact-sound insulation. The SIA 181 standard sets the requirements; an acoustic layer under the new screed avoids disputes with the neighbour below.
  • Connection: hooking underfloor heating up to the building's central heating needs a mixing unit to lower the temperature, hydraulic balancing and often an individual heat meter.

Heating in winter, cooling in summer

With a reversible heat pump or a geothermal probe, the same pipework can circulate cool water in summer. This is underfloor cooling. It is not air conditioning: the gain is around 2 to 3 degrees, with no dehumidification. But it is silent, needs no extra outdoor unit and is very cheap to run, especially with free cooling from a ground probe.

The limit is condensation. If the water is too cold in humid weather, the floor can become damp. A control system with a humidity sensor that keeps the water above the dew point is essential.

How much does underfloor heating cost

Prices vary widely with access, floor area and the chosen covering. The following ballpark figures, excluding VAT, help prepare a budget for a home in Geneva or the canton of Vaud:

  • Pipes, insulation, manifold and room-by-room controls in a new build: about CHF 80 to 130 per square metre.
  • Milling into an existing screed, levelling included: about CHF 90 to 150 per square metre.
  • Low-profile system in a renovation: about CHF 120 to 200 per square metre.
  • Full renovation with demolition, new screed and covering: often CHF 250 to 450 per square metre, depending on the covering.

Heat generation comes on top. Underfloor heating is not subsidised as such, but it is often part of a wider project replacing a boiler or electric heating with a heat pump, which can be. Cantonal programmes almost always require the application to be filed before work begins.

An old underfloor system that heats poorly

Many buildings from the 1970s and 1980s already have underfloor heating. It often heats poorly, and the boiler is not always to blame. Pipes from that era had no oxygen barrier: oxygen passes through the plastic, corrodes the metal parts and forms sludge that gradually clogs the loops.

Power flushing, replacing the manifold, adding a sludge separator and rebalancing often restore good performance without breaking up the floors. It is also a step to plan before connecting an old floor system to a new heat pump.

The most common mistakes

  • Choosing the floor covering after the system, then finding out the dream parquet is not compatible.
  • Leaving out insulation under the pipes, especially above a cellar or garage.
  • Laying the covering on a screed that is still damp, or skipping the gradual heat-up that manufacturers require.
  • A single loop for several rooms without a thermostat in each, when cantonal rules generally require room-by-room control in new builds.
  • Raising the flow temperature to compensate for an undersized system, which cancels out the benefit of the heat pump.

Frequently asked questions

Can underfloor heating be installed in an older apartment?

Yes, in most cases. Milling or a low-profile system keeps door and threshold heights unchanged. You need consent from the landlord or the condominium, a screed in good condition and a solution for acoustic insulation.

Is electric underfloor heating allowed in Geneva or the canton of Vaud?

Not as main heating. Vaud prohibits new resistive electric heating in principle and requires existing systems to be replaced before 2033. In Geneva, connecting it is authorised only in exceptional cases.

How long does the work take?

Milling an apartment takes a few days. With a new screed, add the drying time, often three to six weeks depending on thickness and screed type, before the covering can be laid.

Is underfloor heating compatible with a heat pump?

It is the best combination. The low flow temperature, often 30 to 35 °C, lets the heat pump reach its best efficiency and use noticeably less electricity than with conventional radiators.

Can parquet be laid over underfloor heating?

Yes, if the manufacturer declares it compatible and its thermal resistance stays low. Fully bonded engineered parquet is the best fit; thick solid wood on an insulating underlay should be avoided.