Split-face olivine diabase stones, 10–15 cm, sold in 44 lb boxes. These are the large-format stones — roughly 4 to 6 inches across — designed for Harvia's bigger heaters and wood-burning stoves.

44 lbs of stones, each roughly 4" to 6" across.

Size, and that's the whole difference. The AC3000 is the same stone type at 5–10 cm; these are 10–15 cm. Both are split-face olivine diabase. Which one you need depends entirely on your heater — they aren't interchangeable.

The Harvia Virta and Virta Combi series specify AC3020, and so does the M3 wood-burning stove. Larger heaters need larger stones. Always check your heater's manual before ordering.

Depends entirely on your heater's stone capacity. The Virta series takes 150 lbs, which is four boxes. The M3 wood stove takes 66 lbs, which is two. Check your heater's specification, or tell us the model and we'll tell you exactly how many.

No, unless your heater specifies them. Stone size isn't cosmetic — it determines airflow through the heater. Stones that are too large for a compact heater leave gaps that reduce heat transfer; stones too small for a large heater pack too densely and choke the airflow. Follow the manual.

At best, a heater that doesn't perform as it should. At worst, restricted airflow that runs the elements hotter than designed and shortens their life. It's a cheap mistake to avoid — just check the manual or ask us.

A dense volcanic rock that handles repeated heating and rapid cooling without splitting — which is exactly what a sauna does to stone every session. It's the standard material for quality sauna stones for that reason.

The stones are broken rather than tumbled, leaving angular faces and sharp edges. That shape creates more surface area and gives a crisper, more immediate burst of steam when water hits them, compared to the softer steam from rounded stones.

Follow your heater's manual first — most Harvia heaters specify split-face. Rounded stones like the R-991 are designed for the Spirit series specifically. If your heater calls for split-face, use split-face.

Because they can explode. Ordinary stone often holds trapped moisture or has a layered structure that fails when you pour water on it at 190°F. River rock and granite are particularly risky. Sauna stones are selected and tested for this specific abuse.

Yes — they're selected, cleaned and intended for sauna use, and they carry no Prop 65 warning.

Yes. Rinse them before loading to clear off dust from handling and transport. Otherwise the first few heats will smell of hot dust.

Loosely. This is the single most important thing — stack them so air can move freely between the stones, never wedged tight or forced in around the elements. Good circulation is what keeps the elements cool enough to last.

You choke the airflow. The elements run hotter than designed, the heater works harder to reach temperature, and element life drops significantly. It's the most common cause of premature heater failure and it's entirely avoidable.

Fill to the capacity in your heater's manual — no more, no less. Underfilling exposes elements and wastes steam potential; overfilling restricts airflow and can obstruct the heater's own safety sensors.

Larger stones at the bottom, smaller toward the top, is the general rule — it keeps the base stable and the airflow open. Your heater's manual is the authority if it specifies otherwise.

Some heaters benefit from a mixed load — larger stones at the base for stability and heat capacity, smaller ones above. Check your manual, and ask us if you're unsure whether your heater is one of them.

Once a year for a home sauna. More often for heavy or commercial use.

Look for cracking, crumbling, or stones that have visibly shrunk and settled. If the pile has compacted and airflow looks restricted, or you're finding grit at the bottom of the heater, it's time. Stones are consumable — they don't last forever.

Typically a year or two with regular home use, longer if you sauna occasionally, shorter in a commercial setting. Each heating cycle stresses them a little more.

Degraded stones restrict airflow, the heater runs hotter, and the elements fail early. Replacing a box of stones is considerably cheaper than replacing a heater — this is genuinely the highest-return maintenance you can do.

Yes, once a year. Stones settle and compact over time even without breaking down. Taking them out, checking them and restacking loosely restores the airflow.

Yes, a rinse in plain water is fine and clears accumulated dust. Let them dry before reloading. Skip soaps and cleaning products entirely.

Yes — that's what they're for. Ladle plain water over the stones for löyly, one ladleful at a time. Never pour water directly onto the heating elements themselves.

Only sauna-specific products, diluted in the water bucket rather than poured neat onto the stones. Undiluted oils scorch, stain, leave residue that's difficult to remove, and in some cases can ignite.

No. Salt corrodes the heater, and sugary liquids like beer burn on and leave residue that smells for months. Plain water only — or a proper sauna fragrance in the bucket.

The first heat or two may have a faint mineral smell as any residual dust burns off. Rinsing them before loading minimises it, and it clears quickly.

No, and that's expected — these are natural stone, so every piece is unique in shape and size. Harvia suggest buying an extra box so you can select the best-fitting pieces for your heater and keep the rest as spares. Worth considering given the freight on stone.

It's not required, but it gives you choice on fit and a supply for topping up as stones settle. The trade-off is freight — stone is heavy, and shipping a spare box costs more than the box.

By parcel carrier, in 44 lb boxes. Freight is calculated to your address, and because stone is dense, shipping is a real cost rather than a rounding error. Ask us for a delivered price.

Sometimes, and we'd rather tell you than quietly sell you the freight. If a local sauna supplier stocks proper 10–15 cm split-face stone, buying locally can work out better on a large load — and the Virta series needs four boxes, which is 176 lbs of rock. Just make sure it's genuine sauna stone in the right size.

Yes, and it's usually the sensible way to do it — one quote, one delivery conversation, and we make sure the quantity actually matches your heater's capacity rather than leaving you to work it out.

Tell us your heater model before you order and it won't happen. Stone capacity varies enormously — the Virta takes 150 lbs, the M3 stove 66 lbs, and the Cilindro range needs the smaller AC3000 instead.

No. Sauna stones are a consumable, like brake pads or filters — they're expected to degrade with use and get replaced periodically. That's normal and not a defect.

Yes — the Harvia M3 wood stove specifies AC3020, taking two boxes for its 66 lb capacity. Wood stoves generally take the larger stone size, so these are usually the right choice there.

No. Infrared saunas have no stones and no steam — they heat you directly rather than heating the air and a stone mass. If you have an infrared cabin, you don't need stones at all.

They're just rock — ordinary landscaping material once they've broken down. Drainage, path fill, or general disposal. Nothing hazardous about them.

Freight on stone varies significantly by address and quantity, and most buyers need these quoted alongside a heater. Request pricing and you'll get one delivered figure rather than a number you have to add shipping to.

We're an authorized Harvia dealer. Tell us your heater model and we'll confirm the right stone size and quantity before you spend anything — which matters more than it sounds, because the wrong size or a short order means a second freight charge on something heavy.

Please review our return policy at thesaunarepublic.com/policies/refund-policy. Given the weight and freight cost on stone, it's worth confirming size and quantity with us before ordering rather than after.

Call (302) 273-0861 or email info@thesaunarepublic.com and we'll be glad to help.