Kuuma Sauna Stove FAQ’s

Is the metal heavy enough to prevent warpage?

Yes, under normal operation.  Kuuma Wood-Burning Sauna Stoves are manufactured with American Steel in the United States from a combination of 1/4″, 3/8″ mild steel, and 3/8″ stainless steel to form the most durable sauna stove on the market.

Does my stove need to be cured before using it?

Yes, even though we clean it well, there are still residual oils and preservatives on the steel, plus the high temp paint smokes a bit on initial heating.  It is best to fire your stove outside on a low setting for several hours with at least one 3-4′ section of stove pipe “To create a draft.” The smoke is strong but safe to breathe.

Finished taking a sauna now what?

We highly recommend the Bake and Breathe method (Blog) to keep your sauna stove and sauna in optimal condition.

How long should I leave my draft open when heating my hot room?

The draft should never be left in the high burn position for longer than (5-10) minutes to prevent overheating.  Your hot room should be up to temperature in roughly 45 minutes in a well-insulated hot room.  When the draft lever is left in a full-open position, you send all the heat right up the chimney, and it’s not heating your hot room.  It will also severely overheat the stove.  To heat your hot room effectively, you want to lower the draft lever between 1/8th and 1/4 open after the logs are burning well.  This will heat the hot room and not send the heat up the chimney.

Is it approved to UL standards?

Yes, it’s approved to UL #1482 by PFS. It’s the only one on the market that we are aware of at this time.  This is required by most insurance companies.

Is it brick-lined and baffled?

Yes, it is brick-lined to prevent warpage and, coupled with the baffle, enhances the burning of gases.

How is the steam (löyly) with the Kuuma sauna stove?

Good steam is a key attribute of a great sauna.  The Lämpömassa behind our design results in awesome steam.  Use only clean, mineral-free water (rain or lake water should work great) on your sauna rocks to make steam.  We strongly recommend that you do NOT use water with a high sodium content (think what our cars in MN look like verse ones that don’t see the winter), especially if you don’t practice the Bake and Breathe method because salt, heat, steel, moisture, and paint don’t play nice and will result in premature rusting.

Is it an air-tight stove?

Yes, the only air it gets is what you set on the carburetor. The doors are sealed for airtightness.  If you get the glass window, we have an intentional air gap.

The small gap is intentional (Video). 

Do we supply chimney parts?

No, everything can be sourced locally or online.

For the chimney, a standard 6″ collar comes off of the stove.  Duravent is a good brand, and they carry all the pieces you will need, such as the adapter to go through your ceiling while meeting the proper codes.

In the chimney, you need a damper for backdraft protection. It’s best to put it up high enough for children not to access it.

You can do single-walled pipe from the stove all the way up until you are 18″ below the ceiling.  Then you need to switch over to double or triple wall insulated Class A pipe through the top.

If possible, go straight up from the stove through the ceiling if you must make a 90*, use (2) 45*’s and make a radiant bend instead of a hard 90*.

If you use a chimney cap, it needs to be the open kind.  Don’t use a restrictive chimney cap.  We recommend a chimney hat with no screen, mesh, or restrictions.  This is the one we use, and it works great!  Famco (Wind Directional Chimney Cap)

Blog Post on the Chimney Components

Does my Kuuma stove come with rocks?

No, but we recommend granite or quartz, often found locally at lakes and streams.  Many retail landscaping businesses often sell them as well.  We recommend golf ball size with a slight variation.  Please wash with warm water and soap before installation if you pick your own. Sauna Rocks

What are the sauna combustion air requirements?

Running with the draft wide open, the maximum amount of air consumption is 4 square inches.

Can you heat water for bathing while it heats the room?

Yes, water heats very quickly with the optional 12 or 16-gallon stainless steel hot water tank. It’s very convenient for applications without running water.

Can you see the fire?

Yes, if ordered, an optional 5″ x 8″ glass window is available to watch the burn, provide an additional light source, and make your sauna experience even more romantic and enjoyable.

Is the glass window easy to clean?

If ever needed, it’s easy to clean by dipping a wet rag into ash located in either the firebox or ashpan and wiping, followed by drying with a paper towel.

The small gap is intentional (video).

What size room will it heat?

Based upon how well the heating room is insulated, the small stove is for up to an 8′ x 8′ x 9′ room, the medium is for up to 10′ x 10′ x 9′, and the large is for bigger saunas.

How long should it take to heat my sauna?

Many factors (see blog post) come into play when determining how long it will take to heat your sauna.   What kind of wood are you using?  What material is your sauna constructed out of?  Do you have a damper on your stove pipe?  If so – on normal days, your damper should be closed roughly 50%, and on windier days, it should be about 75%, but of course, it needs to be adjusted specifically for your local conditions.  Otherwise, you could be shooting all of the hot air up the chimney.

What length of wood works best for each sauna stove?

16″ wood lengths for the small and medium sauna stoves. 20″ wood lengths for the large sauna stove.

Can you load wood from outside of the dressing room?

Yes, the 8″ or 12″ optional extensions are used to go through the wall.  We don’t recommend this because an outside feed adds about $1,000 to building construction costs, and you also lose 25% of the heat from the stove, so you need to upsize one stove size.  Almost all stove damage we’ve ever seen due to overheating has been because the draft isn’t properly managed because the control isn’t in the hot room.  If you still want an outside feed knowing this, we will be happy to build it for you.

**Inside versus Outside Feed Blog**

What are the Clearance Requirements (Meet UL standards for insurance)?

• • You always need a 48″ clearance in front of your stove.
  • Using a heat shield, you need a 7″ clearance on the side and 8″ clearance on the back from the shield on the stove to a non-combustible shield on the wall with a 1″ air gap behind it (PDF).
  • If you have heat shields on your sauna but not on the wall or vice versa, you need a 15.5″ clearance on the side and a 13.5″ clearance on the back (PDF).
  • Without heat shields or non-combustible surfaces, you need a 38″ clearance on the side and a 28″ clearance on the back (PDF).
  • A wall heat shield (non-combustible) needs to be 4″ off of the floor and create a total height of 52″.  The width needs to extend past the sauna stove 8″ on each side.
  • If your ceiling is 8′ or less, a 3’x5′ heat shield on the ceiling with a 2″ air gap above it is required (PDF)—Law of Loyly (Bench Height).
  • Clearances to the edge of the non-combustible floor (PDF).

Sauna Building Tips:

Being in the sauna business, we often get many questions about building a sauna.

First Recommendation:

Spend a lot of time on Saunatimes.com, created by Glenn Auerbach.  He has done more research than anyone we know, and you can find nearly any information needed. He also has a great ebook for $25 that has helped hundreds of people build a kickass sauna!

General Recommendations:

• • People typically make the top bench too wide.  We recommend 20-21″.  More than that is uncomfortable to sit on.
  • The second bench is primarily to rest your feet or for sitting on. Again, please don’t install it too low.  If it’s too low, it tends to cut off circulation in the legs for shorter people.  It should be approximately 12″ below the top bench.
  • Ceiling height minimum of 8′.  This avoids needing a ceiling heat shield (ugly)—Law of Loyly (Bench Height). 
  • 1 or 2 steps to get on the second bench.  They should be fixed and not moveable.
  • Attach a handrail to the wall next to the steps to assist with safety when getting on or off the benches
  • Ventilation Blog Post