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The three kinds
Electric stone heaters are the most common in home saunas. Elements heat a basket of stones, and a control panel (on the unit or on the wall) sets temperature and time. Many can be scheduled or controlled from a phone.
Wood-burning stoves heat stones with a fire. They need a chimney, heat shields and clearances to combustible surfaces, and they suit outdoor and off-grid saunas.
Infrared emitters are not heaters in the same sense. They are panels built into infrared cabins and are chosen with the cabin, not separately. See infrared vs traditional.
How sizing works
Heaters are rated in kilowatts. Too small and the room never reaches temperature; too large and it overshoots and cycles. To size:
- Measure the room: length × width × height in feet gives cubic feet.
- Check the heater maker’s chart for that volume.
- Size up for glass doors or walls, uninsulated or log walls, high ceilings, or outdoor use in a cold climate.
As a starting point, many manufacturers use roughly 1 kW per 45–50 cubic feet, with the chart and installation manual taking priority.
Stones and steam
More stone mass generally means softer, longer-lasting steam when you pour water. Use only stones sold for sauna heaters, never river stones of unknown type, and follow the manual on quantity and stacking. Check them periodically and replace cracked ones.
Wiring and installation
- Most electric sauna heaters need a dedicated 240V circuit sized to the heater’s rating.
- Controls, temperature sensors and high-limit cut-offs must be placed where the manual says.
- Keep the clearances to walls, benches and ceiling that the manual lists.
- Use a licensed electrician; many places require a permit.
- Do not run a heater from an extension cord or a shared power strip.
Features worth paying for
- Clear, reachable controls with a timer and safety cut-off
- A stone capacity that suits how much steam you like
- Wi-Fi or scheduling if you want to pre-heat on your way home
- Easy-to-find replacement elements and a meaningful warranty
Frequently asked questions
What size sauna heater do I need?
Use the manufacturer's sizing chart for the heater you are considering. As a rough rule, many makers suggest about 1 kW for every 45 to 50 cubic feet of room volume, then a larger heater if the room has glass, uninsulated or log walls, or sits outdoors in a cold climate.
Can I plug a sauna heater into a regular outlet?
Most traditional electric sauna heaters are hardwired on a dedicated 240V circuit and cannot use a regular outlet or an extension cord. Some small infrared cabins plug into a dedicated 120V outlet. Follow the heater's installation manual and use a licensed electrician.
How many stones does a sauna heater need?
The heater manual specifies the stone weight and type. Use stones made for sauna heaters, stack them loosely so air can flow, and replace any that crumble.
Electric or wood-burning heater?
Electric heaters are convenient, controllable and often programmable. Wood-burning heaters need no electrical circuit and are favored for a traditional feel, but they need a chimney, clearances, tending and fuel.