Description
If you are filling a heater from empty, this is the default answer. Split-face olivine diabase is the stone Harvia ships with its own heaters: angular, so it stacks loosely and air moves through the pile; dense, so it holds heat; and broad-faced, so a ladle of water flashes off a wide surface instead of pooling.
This is the same box the heater option adds. On our Harvia and Finlandia cards the “Sauna stones” choice puts AC3000 in the cart at +$66; buying it here separately makes sense when you are replacing stones that have crumbled, topping up a heater that came half-filled, or ordering a spare so you can sort for fit.
Stones are consumable. Re-stack them once a year and replace what has broken down — packed or crumbling stone chokes the airflow, and that is what actually kills heating elements.
How many boxes do I need?
Every heater states its stone capacity on its own Specifications tab — a wall heater like the KIP or Finlandia FIN takes one 44 lb box, a Cilindro takes five, a Virta Pro six. Order to that number; a heater run below its rated charge overheats its elements.
