Sauna heaters

Types of heater

The more stones a heater holds, the more heat it stores and the softer the steam. See combi saunas for heaters with a steamer.

Sizing a heater

1. Measure the inside of the sauna and multiply length × width × height to get the volume in m³.
2. Add 20 to 25% if it has glass doors or windows, uninsulated walls, tiles or stone, or stands outdoors.
3. Pick a heater rated for that volume. Manufacturers give a range for each heater.

Loghouse fits a 9 kW Harvia heater as standard in its outdoor saunas. See what size sauna for room sizes.

Controls

• Built-in controls: dials on the heater for temperature and a timer. Simple and cheaper.
• Separate control panel: mounted outside the sauna, often with a start-time setting. Some heaters require one.
• App or Wi-Fi control: lets you start heating from your phone, so it's ready when you get home.

Heater prices

Prices in euro as listed in October 2026, from Timbertrove and Finnmark Sauna's Irish store (Finnmark is a UK company). Where a heater comes in several sizes, the price is usually for the smallest. Timbertrove showed the Vega as sold out. Stones are usually extra: about €45 to €51 per 20 kg box.

Fitting a heater

• Electric heaters need a dedicated circuit, installed and certified by a registered electrical contractor. See electrical requirements.
• Follow the safety clearances in the manual: distances to walls, benches and the ceiling, and a guard rail around the heater.
• Wood-burning stoves need a properly installed flue and clearances to combustible materials.