About Löyly Sizer

Löyly Sizer is made in Finland by a sauna owner who got different answers from every heater calculator and wanted to see why. Löyly is the Finnish word for the steam that rises when water hits the hot stones.

How heaters are chosen

A heater appears in the results only when its manufacturer's rated room range covers your calculated volume. The order depends on how close its power is to the recommendation and where your room sits in its range. Commission plays no part.

Heater data

The calculator searches 48 heaters and stoves from 11 brands: Harvia, HUUM, Saunum, Helo, Tylö, Finlandia, Amerec, Tulikivi, Kastor, IKI, Narvi. Each model's rated room range is taken from the manufacturer's own product page or, where that was not available, from a retailer's listing; every model links to its source. Ranges were collected in October 2026 and may change.

Affiliate disclosure

Some product links may be affiliate links. If you buy through one, we may earn a commission at no extra cost to you. This pays for the site and keeps the calculator free.

Privacy

The calculator runs entirely in your browser. The numbers you enter are not sent anywhere.

Contact

Corrections to heater data are welcome: hello@thesaunasizer.com