Smart Electric Heater 2026: Buying Guide and 5 Models Worth Knowing

Which smart electric heater should you choose in 2026?

For a fixed installation, the Thermor Equateur 4 is the most complete option: a dual heating body with cast-iron inertia, open window and presence detection, and control through the Cozytouch app. If you want a portable unit you simply plug in, the Mill Gentle Air WiFi oil-filled radiator offers a polished app and an open window function, with no electrician needed.

Between those two, the Atlantic Oniris focuses on design and responsiveness, the Sauter Orosi 2 on entry-level fluid inertia, and the Rointe Kyros WiFi on built-in Wi-Fi that needs no gateway. This guide is based on manufacturer specifications, published independent reviews and verified buyer feedback. For related devices, see our smart space heaters page.

The criteria that really matter

Type of heating body

“Inertia” covers several technologies, and marketing sheets often blur them:

• Fluid inertia: an element heats a sealed thermal fluid. Heat is soft and even, warm-up is reasonable. This is how the Sauter Orosi 2 and Rointe Kyros WiFi work.
• Cast-iron inertia: a cast-iron block stores heat and releases it slowly. Paired with a fast-reacting heating front panel, it is called “dual technology”, as on the Thermor Equateur 4.
• Aluminium body with heating front: less storage, more responsiveness. This is the Atlantic Oniris design.
• Dry stone or ceramic inertia: refractory bricks store heat for longer. Best for rooms heated over long periods.
• Glass front: ranges such as Campa’s Campaver combine a thick radiant glass front with rear heating elements. The main appeal is design, not stone storage.
• Portable oil-filled: a free-standing oil radiator you plug into a socket. It is a supplementary heater with no installation, like the Mill Gentle Air WiFi.

The more inertia, the longer the room stays warm after switch-off, but the slower the heater reacts to a new set-point. High inertia suits rooms used all day; responsiveness matters more for rooms used occasionally.

Built-in Wi-Fi or gateway

This is the most misunderstood point. Thermor, Atlantic and Sauter heaters (all part of Groupe Atlantic) use the Cozytouch app, but depending on the model you need a gateway (the Cozytouch bridge) connected to your router. The Rointe Kyros WiFi and Mill Gentle Air WiFi have Wi-Fi built in: the app is enough. Check this before buying, as it changes both cost and setup.

Pilot wire

The pilot wire (fil pilote) is specific to France: a dedicated conductor sends orders (Comfort, Eco, Frost protection, Off, and on six-order versions Comfort -1 and Comfort -2) from a central programmer. If your home has one, choose a compatible heater. Plug-in portable heaters do not need it.

Automatic detection

Two features make a real daily difference. Open window detection cuts or reduces heating when the temperature drops sharply during airing. Presence detection lowers the set-point when the room is empty. The fixed models in this guide offer both on most versions; the Mill Gentle Air WiFi offers the open window function and predictive start.

Power

A common rule of thumb is about 100 W per m² in a home with average insulation, less in a recent well-insulated home, more in an older building. For accurate sizing, a heating professional will account for volume, orientation and actual heat losses.

5 models worth knowing

Thermor Equateur 4: the most complete

The Equateur 4 combines a cast-iron heating body with a heating front panel. It comes in skirting, horizontal and vertical formats from 750 to 2000 W and is made in France. It includes open window and presence detection, and is controlled remotely via Cozytouch, with energy monitoring and voice control through Google Assistant.

Strengths: gentle cast-iron heat, responsive front panel, wide range of formats, mature app.

Limits: fixed heater to be installed, Cozytouch gateway required for remote control, premium positioning.

Best for: homeowners replacing convectors who want durable equipment for living areas.

Atlantic Oniris: responsive design

The Oniris uses an aluminium heating body and a fast-warming heating front. Its digital touch control unit and extra-flat front suit contemporary interiors. It offers open window and presence detection and is controlled via Cozytouch (optional gateway), including by voice with Google Assistant.

Strengths: refined look, responsiveness, same ecosystem as Thermor.

Limits: less heat storage than cast-iron or stone, gateway needed for remote control.

Best for: living rooms where design matters as much as performance.

Sauter Orosi 2: affordable fluid inertia

The Orosi 2 is a fluid-inertia heater with a digital thermostat, presence and absence detection, window opening detection and PIN lock for settings. Remote control uses a connectivity box from the Cozytouch ecosystem. It carries NF Électricité certification.

Strengths: even heat, complete automatic functions, entry-level positioning among French brands.

Limits: connectivity relies on a separate box, more classic design.

Best for: households equipping several rooms who want the best balance of features and budget.

Rointe Kyros WiFi: built-in Wi-Fi, no gateway

The Kyros WiFi from Spanish maker Rointe is a wall-mounted thermal-fluid radiator with a recycled aluminium body. Its Wi-Fi module is built in: you set it up and schedule it directly in the Rointe app, with energy monitoring, open window detection and early start. It is offered in 600, 1200 and 1800 W versions among others.

Strengths: no gateway to buy, built-in energy monitoring, available from several online retailers.

Limits: pilot wire not highlighted, smaller distribution network in France than Groupe Atlantic brands.

Best for: anyone who wants a connected fixed heater that is simple to commission, with no extra hub.

Mill Gentle Air WiFi: portable, no installation

The Gentle Air WiFi from Norwegian brand Mill is a free-standing oil-filled radiator with a closed shape. The 1500 W version has three power levels (600, 900 and 1500 W) and targets rooms of roughly 18 to 22 m²; a 2000 W version also exists. It connects over Wi-Fi (set up via Bluetooth) to the Millheat app, with scheduling, an open window function and predictive heating. It has tip-over and overheat protection.

Strengths: no installation, clear app, easy to move between rooms.

Limits: supplementary rather than main heating, takes floor space, no pilot wire.

Best for: renters, home offices, guest rooms or poorly heated rooms.

Comparison table

Mistakes to avoid

• Forgetting the gateway: a “connectable” heater is not always connected out of the box. Check whether a bridge or box is required.
• Choosing maximum inertia everywhere: for a guest room or office used a few hours a day, a responsive model fits better.
• Undersizing power: an underpowered heater runs constantly without reaching the set-point.
• Plugging a portable heater into a power strip or an undersized smart plug: use a wall socket, and only a smart plug explicitly rated for the heater’s power.
• Buying an unknown brand: without a reliable app publisher, the connected features may stop working after a few years.

Installation and safety

A fixed heater should be connected by a qualified electrician, on a circuit suited to its power and compliant with local wiring rules, including bathroom safety zones. Never cover a heater and keep the clearance recommended by the manufacturer. Place portable models on a stable surface, away from curtains and laundry, and check they have tip-over protection.

On the regulatory side, EU ecodesign Regulation (EU) 2015/1188 has set efficiency requirements for local space heaters since 2018, which made electronic thermostats and weekly scheduling standard. For whole-home heating control, read our smart home energy saving guide and our article on the smart thermostat with a heat pump.

Our verdict

To replace convectors in a home you own, the Thermor Equateur 4 remains the most complete reference. To equip several rooms on a controlled budget, the Sauter Orosi 2 covers the essential automatic functions. If you cannot do any works, the Mill Gentle Air WiFi is the simplest connected supplementary heater. The Atlantic Oniris and Rointe Kyros WiFi round out the choice for design-led interiors and for those who want to skip the gateway.