The Harvia AC4000 stones are decorative stones, not primary heating stones. They are intended to be placed loosely on top of standard sauna stones to maintain airflow and protect heating elements from direct contact.
When installed correctly, these stones help create a visually appealing steam effect while preserving proper heater function. For best results, the stones should be rinsed before use and arranged gently without compacting, ensuring optimal circulation and long-term durability.
These stones are best suited for sauna users who value aesthetic refinement alongside traditional sauna performance.