Most outdoor saunas require a 240V trench. This one does not. The Solaris Small is the world’s first solar-powered, off-grid electric sauna: 3 kW Harvia KIP heater running off integrated rooftop panels and an onboard battery bank. Named to TIME’s Best Inventions of 2025 list. 86 by 60 inches, two to three people, Tile Oak cladding inside and out, Brushed Alder benches, solar-tinted panoramic glass, RGB LED therapy. No chimney, no service drop, no wood pile. Built in Finland by Kirami. Twelve-week build, ships free.