Harvia Vulcanite Sauna Heater Stones, Split-Face, 5-10cm (AC3040)

The durable Harvia AC3040 is a vulcanite sauna stone designed to perform at fluctuating temperatures with maximum efficiency. Sold in 44.1 lbs (20 kg) boxes. Supplied in black.

With volcanic origins dating back millions of years, the fine-grained dark grey sauna stones shine black when wet for a beautiful, versatile look to compliment any sauna interior. Split-face stones store plenty of heat, are easy to stack, and enable strong air circulation for efficient and plentiful steam when water is poured upon them.

• Sauna heater stones are made of fine-grained, dark grey volcanic rock that turns black when wet for a unique touch.
• Split-face design stores plenty of heat, making water vaporize efficiently when splashed on the broad surface.
• Easy to stack with good air circulation, high thermal conductivity, and excellent resistance to heat fluctuations.
• Compatible with electric sauna heaters or as surface layer stones for wood-burning sauna stoves.

This item is not tied to a specific heater or stove model — it suits any Harvia sauna.

• Sauna stones are not a decorative topping — they are the thermal mass that makes a sauna a sauna.
• Rinse before loading to wash off dust.
• Stack loosely by hand, largest at the bottom. Never wedge, hammer or pack them.
• Re-stack once a year and replace any that have split or crumbled.

How many boxes of stones do I need?

Each box holds 44 lb, except the rounded R-991 at 33 lb. Your heater's product page gives its stone capacity and the number of boxes Harvia specifies. Order one box more than the minimum so you can set aside any that will not stack cleanly.

How often should sauna stones be replaced?

Re-stack them once a year and replace any that have cracked or crumbled. Stones break down with thermal cycling, and a bed of broken fragments chokes the airflow the heater needs to survive.