About Saunalaskuri

Saunalaskuri (Finnish for "sauna calculator") is an independent, self-funded project that helps people in Finland plan, build and run their saunas. The site is in Finnish; this page summarises it in English.

What we do

Saunalaskuri publishes 12 free calculators in three groups: the heater (power in kW, sauna stones, heating time, safety distances), the room (sauna size, bench heights, ventilation, insulation) and running costs (electricity, firewood, water and yearly totals). Each calculator shows its formula and its sources: the Finnish sauna design card RT 91-10440, the heater safety standard SFS-EN 60335-2-53, the Finnish Safety and Chemicals Agency (TUKES) and the published guidance of heater manufacturers such as Harvia, Helo and Narvi. Seven practical guides cover sizing, stones, benches, floor plans and energy use.

Saunasuunnittelija: our sauna-planning assistant, built on Claude

Saunasuunnittelija ("sauna planner") is an assistant, currently in beta, that lets people describe their sauna in their own words, in Finnish, instead of filling in one form at a time. It runs on Anthropic's Claude API. Claude uses tool calls to run the site's own 12 calculators, so every figure comes from the same audited formulas as the calculator pages, and each answer links to the calculators it used. It can chain them — room size to heater power to stones to heating time to cost per session — and it states the assumptions it made.

The assistant has explicit limits. Electrical connection of a heater is always left to an authorised electrician, manufacturer installation manuals take precedence over general safety distances, and health questions go to a doctor. Conversations are not stored by Saunalaskuri.

Who is behind it

Saunalaskuri was founded and is built by Sebastian Orona, working from Argentina for a Finnish-speaking audience. The project started in May 2026 and was registered as a business in July 2026. It is self-funded, with no outside investors.

Timeline

• May 2026 — saunalaskuri.com launched with its first three calculators.
• June 2026 — all 12 calculators live across three categories.
• July 2026 — business registered.
• August 2026 — guides section with seven practical guides; redesigned home page.
• October 2026 — Saunasuunnittelija assistant opened in beta.

Contact

Write to [email protected]. We read every message and reply within five working days.

Last updated: October 2026.