Yes, you can preheat a sauna with WiFi control. A WiFi-enabled electric sauna heater lets you start the heating process remotely using a smartphone app, so the sauna is ready and waiting at the right temperature when you walk in. This works through a WiFi controller paired with your heater and a free mobile app. Below, we answer the most common questions about how remote sauna heating works in practice.
How does WiFi sauna control actually work?
WiFi sauna control connects your electric sauna heater to your home network through a dedicated controller. You manage the heater from a smartphone app, sending commands over the internet to the controller, which then adjusts the heater directly. The whole system works from anywhere with a mobile data or WiFi connection, not just from inside your home.
The controller sits either inside or outside the sauna room and communicates with the heater’s power unit. A temperature sensor monitors the sauna room temperature and feeds that data back to the app in real time, so you can see exactly how warm the room is getting. A door switch is included as a safety feature, cutting power to the heater if the sauna door opens unexpectedly during remote operation.
Our Narvi Flow WiFi controller works on this exact principle. You open the app, tap to start the heater or set a timer, and the controller handles everything from there. The app is free and available on both iOS and Android.
What temperature can you set when preheating remotely?
When preheating a sauna remotely via a WiFi app, you can typically set the target temperature within the same range as the physical controller, usually between 40°C and 110°C (104°F to 230°F). The app sends your chosen temperature to the controller, which runs the heater until the sensor reads that temperature in the hottest part of the room.
One thing worth knowing: the temperature shown in the app reflects what the thermostat sensor reads, which is placed at the hottest point in the sauna, typically 10 cm below the ceiling above the heater. The reading on a wall thermometer elsewhere in the room will be lower. This is intentional. Monitoring the hottest spot is a safety requirement, not a flaw in the system.
For a typical home sauna session, most people set the target somewhere between 70°C and 90°C. For a softer, steamier experience, a lower temperature combined with generous löyly works well. For a more intense heat, push it higher.
How long before your sauna is ready after a remote start?
Heating time depends on the size of the sauna room, the power of the heater, and the starting temperature of the room. A small home sauna of around 4 to 6 cubic metres with a properly sized electric heater typically reaches bathing temperature in 30 to 45 minutes. Larger rooms or heavily insulated log structures take longer, sometimes 60 to 90 minutes.
This is exactly where remote preheating saves you time. Instead of waiting around after you get home, you start the heater from your phone while you are still on your way. By the time you have changed and poured yourself a drink, the sauna is ready.
The WiFi app lets you either start the heater immediately or schedule a specific start time. Scheduling is useful when you know exactly when you want to bathe. The immediate start is handy when your plans are more spontaneous.
Is it safe to preheat a sauna when no one is home?
Yes, preheating a sauna remotely is safe when the heater and controller are properly installed and meet current safety standards. Modern WiFi sauna controllers include built-in safety features specifically designed for unattended operation. These include a door switch that cuts power if the sauna door opens, overheating protection sensors, and a maximum operating time limit that prevents the heater from running indefinitely.
A few practical points matter here:
- The heater must be installed by a certified electrician. This is not optional. Electric sauna heaters must not be connected through an RCD (residual current device) according to standard 60364-7-703, and only a qualified electrician understands these requirements.
- The door switch included with WiFi controllers acts as a physical safety interlock. If someone opens the sauna door while the heater is running remotely, the system responds.
- Overheating protection is built into the system at the sensor level, separate from the main temperature control.
- Always follow the maximum operating time settings in your controller. These exist for a reason.
Remote preheating has become a standard feature in Finnish homes and community saunas precisely because the safety systems work reliably when the installation is done correctly.
Which Narvi sauna heaters support WiFi control?
Our electric sauna heaters that come with the Narvi Flow controller support WiFi control. Most of our standard electric heater models are available with the Flow WiFi controller included, and the controller can also be purchased separately and connected to our e-model heaters (models without a built-in controller).
The range covers heaters from compact wall-mounted units for small home saunas up to floor-standing models for larger spaces. If you already own a Narvi e-model electric heater, you can add WiFi control by purchasing the appropriate Narvi Flow WiFi Controller package separately. There are two versions: one for heaters under 11.0 kW and one for heaters between 11.0 and 18.0 kW.
The Narvi Flow WiFi controller is also well suited to community saunas, rental cabins, and hotel saunas. Its Easy Mode and On/Off Mode let you lock down the settings so guests can only switch the sauna on and off, while the temperature and timing stay preconfigured by the operator.
Browse the full range of heaters and controllers to find the right combination for your sauna.
What do you need to set up WiFi sauna control at home?
To set up WiFi sauna control, you need four things: a compatible electric sauna heater, a WiFi sauna controller, a home WiFi network that reaches the sauna, and a certified electrician to handle the wiring and connection.
Here is what the setup involves in practice:
- Choose a compatible heater. Any of our electric heaters with a Flow controller included, or an e-model heater paired with the appropriate Flow WiFi controller package.
- Book a certified electrician. The controller and heater must be wired by a professional. This covers both the power connection and the correct placement of the temperature sensor and overheating protection sensor.
- Place the temperature sensor correctly. It goes 10 cm below the ceiling, above the heater. This is the hottest point in the room and the correct monitoring location for safety.
- Connect the door switch. This is included with the WiFi controller and must be fitted to the sauna door as part of the installation.
- Download the Narvi Flow app. Available free on the App Store and Google Play. Once the controller is connected to your WiFi network, the app pairs with it and you are ready to go.
Optional additions include a humidity sensor, lighting connection (up to 100 W), and extension cables for the controller if the cable needs to reach further. The controller itself is splash-proof (IPX5), so it can be installed inside the sauna room if that suits your layout.
WiFi sauna control is one of those upgrades that genuinely changes how you use your sauna. You stop planning your evening around the heater and start planning the heater around your evening. We have been making electric sauna heaters in Rauma, Finland since 1937, and the Narvi Flow controller is our answer to making that experience as effortless as possible. If you want to find the right heater and controller combination, our local dealers carry stock and can advise on installation. Find your nearest dealer here. If you have specific questions about compatibility or setup, get in touch with us directly and we will help you find the right solution.