Heater Sizing for 6x8 and 8x10 Saunas

Published March 2026 - Heater Sizing

Heater sizing is one of the most important decisions in sauna design. The right heater warms the room efficiently and maintains steady heat. For common sizes like 6x8 and 8x10, we start with room volume and then adjust for insulation quality, glass, and exterior exposure.

Quick Heater Sizing Guidelines

Room SizeTypical Heater RangeNotes
6x8 (approx. 7-8 ft ceiling)6-8 kWAdjust upward for glass doors or exterior walls.
8x10 (approx. 7-8 ft ceiling)9-10.5 kWHigher end for outdoor or poorly insulated rooms.

What Changes the Heater Size?

Electric vs. Wood-Fired

Electric heaters are common for residential saunas and have consistent output. Wood-fired heaters can provide a different experience but require additional planning for clearances and venting. We design for both depending on your goals.

Need Heater Sizing Help?

We can size the heater and provide electrical planning in your design package.

Heater Sizing & Electrical Planning

For a full design package, visit our Sauna Design in South Lake Tahoe page or get started here.