Connect your sauna heater to a hardwired mechanical timer, a properly rated smart switch, or a dedicated sauna controller with built-in scheduling, then set the preheat to finish about 10 minutes before you plan to get in so you're not paying to heat an empty room.
You spent good money on that sauna, and you're using it regularly. But if you're heating it up and letting it idle while you shower, answer emails, or convince yourself to actually get in, you're wasting energy and money.
The fix is simple: a timer or smart device.
Here is exactly how to set up your sauna so it uses power only when it needs to, without sacrificing heat quality or safety.
Why Saunas Waste Energy (And How Much)
A typical electric sauna heater draws between 4.5 kW and 9 kW. Running that for an hour costs somewhere between $0.60 and $1.50 depending on your local electricity rates. That does not sound like much until you multiply it by daily use.
The bigger waste is the warm-up period. Most saunas take 30 to 45 minutes to reach temperature. If you heat it up and then get distracted, that is 45 minutes of full-power draw with nobody inside. Do that three times a week and you are burning an extra $75 to $150 per year on heat that evaporated into an empty room.
A timer or smart switch eliminates that waste.
The Three Options for Controlling Your Sauna
Option 1: A hardwired mechanical timer
This is the simplest and most reliable solution. A mechanical timer installed between your sauna heater and the power supply acts like an old laundry room timer. You set how long the heater runs, and it shuts off automatically.
Most sauna-specific timers allow up to 60 or 90 minutes of run time. You turn the dial, the heater starts, and when time runs out, the power cuts. No apps, no WiFi, no failure points.
The downside: you have to walk to the timer to start it. That means if you want the sauna ready when you get home, you are out of luck unless you install a timer that can be set to start later.
Best for: Men who sauna at consistent times and want zero complexity.
Option 2: A smart plug or smart switch
If your sauna heater plugs into a standard wall outlet (common with smaller infrared saunas), a smart plug rated for the correct amperage works. You control it from your phone. You can set schedules, turn it on from the driveway, or shut it off remotely if you forgot.
For hardwired saunas (most traditional Finnish saunas), you need a smart switch rated for the heater's load. This is not a standard light switch. You need a contactor-rated smart switch that can handle 30 to 60 amps depending on your heater. Do not guess. If you are not comfortable with electrical work, hire an electrician.
The advantage: you can heat the sauna on your schedule. Set it to start 45 minutes before you typically finish work. Walk in, and it is ready.
The risk: smart devices fail. WiFi goes down. Firmware updates break things. If your smart switch fails in the "on" position, your sauna could run indefinitely. That is why you never rely on a smart device as your only safety mechanism. The heater should still have its own built-in overheat protection and a separate limit thermostat.
Best for: Men who want remote control and schedule flexibility.
Option 3: A dedicated sauna controller with scheduling
Some modern sauna heaters come with digital controllers that include built-in timers and scheduling. Brands like Harvia, Tylo, and Saunacore offer controllers that let you set daily or weekly start times.
These are the gold standard. The timer is integrated into the heater's safety system. You set Monday through Friday to start at 5:30 PM, and the sauna handles the rest. The heater still has all its built-in safety limits. You are not adding a failure point, you are using a feature that was designed for the system.
The downside: cost. A new controller can run $200 to $600, and retrofitting it to an older heater may not be possible.
Best for: Men building a new sauna or upgrading an existing system.
Practical Protocols That Save Energy
Preheat only what you need
A sauna does not need to sit at full temperature for 30 minutes before you use it. Most saunas are ready to enter when they reach temperature. The stones need time to heat if you are using a traditional Finnish sauna with löyly (steam), but that takes about 20 minutes after the air is hot, not 45 minutes of preheat.
Set your timer so the sauna reaches temperature 10 minutes before you plan to enter. That gives the stones time to absorb heat without wasting 30 extra minutes of run time.
Use the residual heat
After your session, the sauna stays hot for 30 to 60 minutes depending on insulation. If you plan to do multiple rounds with breaks between, do not turn the heater off and on. Leave it running at a lower setting or let the residual heat carry you through. One long continuous session uses less energy than two separate heat-ups.
Match session length to heater size
A heater that is too large for your sauna room will cycle on and off more frequently, wasting energy. A heater that is too small will run constantly, also wasting energy. The general rule is 1 kW of heater power per 45 to 50 cubic feet of sauna room volume. If your heater is oversized, a timer that limits run time becomes even more important because the room will reach temperature faster than expected.
What Not to Do
- Do not use a standard dimmer switch to control sauna heat. Sauna heaters are resistive loads. Dimmer switches are not rated for that current and will fail, potentially causing a fire.
- Do not use a WiFi smart plug rated for 15 amps on a heater that draws 20 amps. Read the label. If the heater's amperage exceeds the smart device's rating, hardwire a contactor instead.
- Do not set the timer to run overnight while you sleep. Saunas are designed for supervised use. Running unattended increases fire risk even with safety systems.
A timer or smart device saves you roughly 15 to 25 percent on sauna energy costs by eliminating idle heat time. That is about $50 to $100 per year for a daily user. The device pays for itself in one to two seasons.
The safest setup is a hardwired timer or a dedicated sauna controller. Smart switches work but require proper electrical rating and should never be your only safety mechanism.
Set your preheat to arrive 10 minutes before you do. Use the residual heat between rounds. Match your session length to your heater size.
And if you are still manually running to the basement to turn the sauna on and then forgetting about it for an hour, stop. You are paying for heat nobody is using.
Frequently asked questions
how much energy does a sauna waste when left idling
A typical electric sauna heater draws between 4.5 kW and 9 kW, and most saunas take 30 to 45 minutes to reach temperature. If you heat it up and get distracted, that's full-power draw with nobody inside. Doing that regularly can cost you an extra $75 to $150 per year on wasted heat.
can I use a smart plug to control my sauna
You can use a smart plug on smaller infrared saunas that connect to a standard wall outlet, but only if the plug is rated for the heater's amperage. For hardwired traditional saunas you need a contactor-rated smart switch that can handle the heater's load, and a smart device should never be your only safety mechanism.
how much can a timer save on sauna energy costs
A timer or smart device can save roughly 15 to 25 percent on sauna energy costs by cutting out idle heat time. For a daily user that works out to about $50 to $100 per year, meaning the device can pay for itself in one to two seasons.
what is the safest way to put a sauna on a timer
The safest options are a hardwired mechanical timer or a dedicated sauna controller from the heater manufacturer, since both keep the timer integrated with the heater's existing safety systems. Smart switches add flexibility but require correct electrical ratings and should always be backed up by the heater's own built-in overheat protection.