What size heater does your sauna need?
A sauna heater is sized to the interior volume of the room, not the number of seats. Two cabins that both seat four can need different heaters if one has a full glass front or a higher ceiling. Work out the volume first, then narrow the list.
Undersizing is the common mistake. A heater that is too small will run constantly, take far longer to reach temperature and may never hold it on a cold day. Oversizing wastes money and can overheat a small room.
Starting points by output
| 4.5 kW | Rooms up to roughly 140 cubic feet. Compact one and two-person cabins. |
|---|---|
| 6 kW | Roughly 140 to 185 cubic feet. The most common size for a two to four-person home cabin. |
| 8 kW | Roughly 185 to 250 cubic feet. Four-person cabins and barrels. |
| 9 kW | Roughly 210 to 280 cubic feet. Larger cabins, or a room with a lot of glass. |
These ranges are ours, not the manufacturer's.
They are a starting point for narrowing the list, published so you can make a decision without calling us. Glass area, ceiling height, insulation and whether the room is indoors or outdoors all move the answer, and the installation manual for your specific cabin and heater governs. Tell us which sauna you have and we will confirm the size in writing before you order.
Our saunas and what fits them
The SaunaLife cabins we carry ship without a heater, deliberately, so you can choose electric or wood-fired and size the output yourself. Published interior volumes and the range we suggest for each are in the sauna heater sizing guide.
The Blisspod Prague barrels arrive with a 6 kW Toule heater, and the Turku, Helsinki, Vassa and Tampere Finnish barrels arrive with an 8 kW Harvia and WiFi control. Those are complete and need nothing from this page.
Electric or wood-fired
This decides siting, budget and how the sauna actually gets used, so settle it before you compare models.
| Electric | Set a temperature and walk away. Needs a dedicated circuit run from your panel to the sauna, which means a licensed electrician and often a trench. Easiest where the sauna is near the house or power is already nearby. |
|---|---|
| Wood-fired | No electrical supply at all, which is why it wins at the bottom of a garden. In exchange it needs a flue, correct clearances and somewhere dry to keep wood. You light it and wait, which some people consider the point and others consider a chore. |
Wood-fired outputs do not compare to electric ones.
A wood stove rated at 16.5 kW is not twice the heater that an 8 kW electric is. The two are measured differently, and a wood stove is matched to a room-volume range the manufacturer publishes rather than to the kilowatt figure. Do not read across from the table above. Tell us the room and we will confirm which stove the manufacturer rates for it.
What is actually in the box
This is the most common surprise on a heater purchase, and it is the reason two heaters at the same output can sit a thousand dollars apart.
| Heater only | The heater unit. On most electric models the controller and the stones are separate purchases. The listing says which. |
|---|---|
| Package | Listings marked Package include the controller, and on some models the stones and mounting kit as well. The HUUM DROP and HIVE packages include the UKU controller. The listing states exactly what is in the box. |
| Combi | A heater and steam generator in one unit, for humidity without pouring water. Harvia Virta Combi models are the ones here. |
Stones
Every traditional heater needs stones, and on most models they are not included. The quantity is specified by the heater, not by taste. We carry rounded stones in 33 lb and 44 lb boxes, and the listing for each heater states how much it takes.
Controllers
An electric heater needs a controller unless it has built-in controls. Built-in means the dial is on the heater itself, which is simpler and cheaper but means setting the temperature inside a hot room. A separate wall or app controller lets you preheat from the house. The HUUM UKU is app and WiFi capable; Harvia offers both built-in and separate control depending on model.
Before you order
- Confirm the interior volume of your cabin — length, width and height of the room itself, not the exterior.
- Check your electrical panel. Electric sauna heaters in this range run on 240V and need their own dedicated circuit sized to the heater. This is not a wall outlet. Several manufacturers void the warranty if the connection was not made by a licensed electrician.
- Decide where the controller goes if the heater takes a separate one, because that is a second cable run.
- Add stones to the order unless the listing says they are included.
- For wood-fired, plan the flue and the clearances before anything else. That is a roof penetration on most cabins.
Send us a photo of your panel and the model of sauna you have, and we will tell you what is involved before you spend anything.
Common questions
Can I put any heater in any sauna?
No. The heater has to be rated for the room volume, and the cabin manufacturer usually specifies a type and sometimes an approved list. Check the cabin's manual as well as the heater's, and ask us if the two do not agree.
How do I calculate interior volume?
Multiply the interior length, width and height of the room in feet. A room with a large glass door or glass wall behaves as though it were bigger, because glass loses heat far faster than insulated timber, so size up when a cabin has a full glass front.
Do I need 240V?
For the electric heaters on this page, yes, and it has to be a dedicated circuit sized to the specific heater. The requirement is on each listing. An infrared sauna is a different thing entirely and several of ours run on 120V; see infrared saunas if that is what you were after.
What is the difference between a pillar heater and a wall heater?
A pillar heater such as the Harvia Cilindro stands on the floor and holds a tall column of stones, which gives a softer, more even steam and takes up floor space. A wall-mounted heater keeps the floor clear in a small room. The heat is the same; the footprint and the look are not.
Can I install it myself?
The heater can usually be mounted by the person building the sauna. The electrical connection cannot. Any electric heater here needs a licensed electrician for the final connection, and doing it yourself will void the warranty on most models. A wood stove needs the flue installed to the manufacturer's clearances, which is work most people have done.
How long until it is hot?
An electric heater sized correctly to the room generally takes somewhere between 30 and 60 minutes depending on the cabin, the outdoor temperature and the insulation. A wood stove takes longer and needs tending. The manufacturer's figure is on the listing where they publish one.
Not sure which one? Call 866-427-8202
Tell us the sauna you have or are buying, the interior dimensions, and what is at your electrical panel. We will confirm the output in writing before you order rather than after the crate arrives.
Or email support@homemedspa.com.
Sauna heaters reach high surface temperatures and present burn and fire risks if installed or used incorrectly. Follow the manufacturer's installation manual and clearance requirements, have electrical work done by a licensed electrician, and supervise children. These products are intended for general wellness and relaxation. They are not medical devices and are not intended to diagnose, treat, cure, or prevent disease.
