ThermaSol Astra Indoor Glass Sauna Cabin 4 Person

A Sauna That Belongs in the Room

Most home saunas look like something you tuck away. The Astra looks like something you design a room around.

A clean-lined corner layout with a panoramic clear-glass front framed in brushed Tyrol wood, it sits open and airy against any interior - no cramped wooden box, just wood, glass, and light. Step inside, settle onto the smooth thermo-aspen benches, and let the 9kW Harvia Virta build a deep, even warmth - adjustable up to 194°F - held exactly where you want it by multi-layer wood-fiber insulation. A full-spectrum LED backrest with independent controls sets the mood, and the Harvia Xenio touchpad lets you schedule sessions, set a delay start, and pre-heat from your phone through the MyHarvia app. The world stays on the other side of the glass.

The Astra is built from natural Tyrol wood and thermo-aspen, left raw and untreated on the inside the way a real sauna should be - a living material with its own grain and character, one that warms, breathes, and ages with the room rather than a sheet of laminate pretending to be wood.

And it's meant to be built in, not merely delivered. The Astra arrives as pre-finished panels and goes together in clear phases - walls, benches, ceiling, glass - over a weekend, with two to four people, a few common tools, and no crane or contractor. It sits right on your existing level, water-resistant floor - tile, concrete, vinyl, or laminate - and the corner layout comes left- or right-handed to fit your space. The sauna you helped raise becomes part of the house in a way a wheeled-in box never is.

For the home where the sauna isn't hidden away but built in - a quiet, beautiful fixture of the life you live indoors.

• Indoor corner sauna with a panoramic clear-glass front - open and airy, never cramped
• Natural Tyrol wood interior, left raw and untreated, with smooth thermo-aspen benches and backrest - a material that ages beautifully with the room
• 9kW Harvia Virta heater (up to 194°F) with Harvia Xenio Wi-Fi control + MyHarvia app
• 12-hour delay start and weekly scheduling - pre-heat on your terms
• Full-spectrum LED backrest with independent mood-lighting controls
• Multi-layer wood-fiber insulation for efficient, consistent heat
• Left- or right-corner layout; seats 4-5
• Pre-finished panels assembled in clear phases - a weekend project for two to four people, no crane
• Sits on your existing level floor; can be disassembled and relocated
• Requires a dedicated 240V/40A circuit and a 4.3" vent ducted to the outside - plan placement accordingly
• Included: sauna stones, control, sensor, 2 headrests, and wood platform

Sauna use isn't right for everyone. Consult your physician before use, especially if you are pregnant or have a heart condition, high or low blood pressure, or any cardiovascular or other medical concern. Begin with shorter, lower-heat sessions, hydrate, avoid alcohol before use, don't exceed ~30 minutes, and supervise children. Use only clean water on the stones. Install indoors in a dry, climate-controlled space, keep the vent connected and unobstructed, and leave benches uncovered in use.

• Free shipping in the continental US; cost quoted by location
• Delivered via flatbed trailer with on-site offloading, ~12-13 weeks; notified ~2 weeks ahead
• Assembly is a guided, multi-phase build (walls, benches, ceiling, glass) - plan on two to four people and a weekend, using common tools (drill with cross-head and torx bits, level, ladder, rubber mallet)
• The tempered-glass panels require careful two-person handling during install - the edges can shatter on a hard knock, so the glass goes in last and slow
• Plan your space: the cabin is 87" x 87" x 83", but you need a minimum assembly clearance of 110" W x 110" D x 107" H, a room ceiling height of at least 8', and a 2" air gap between the unfinished cabin sides and adjacent walls
• Ventilation: the sauna requires a 4.3" vent connected to a duct that leads outside the wall cavity, to carry warm, moist air away from the structure. This affects where the Astra can go - choose a room where that duct run is possible
• Sits directly on existing level, water-resistant flooring (concrete, ceramic tile, vinyl, or laminate)
• Electrical (heater, control, lighting) is wired during assembly; the heater requires a dedicated 240V, 40-amp circuit installed by a licensed electrician (lighting 110V). All electrical work must be done by a licensed electrician
• The Astra can be disassembled and relocated by a professional if you move - though the glued ceiling frame, glass handling, and vent connection mean it's a planned job, not a quick shuffle

Download the ThermaSol Astra specification sheet (PDF)

Is the Astra an indoor or outdoor sauna?
Indoor. It's designed to sit inside a dry, climate-controlled space on an existing level floor, with a panoramic glass corner front that blends into modern interiors.

How many people does it seat?
Four to five, in an 87" x 87" corner layout (53 sq ft interior).

How hard is it to assemble?
It's a guided, multi-phase build rather than a flat-pack chair. Plan on two to four people over a weekend, with common tools - a drill, level, ladder, and rubber mallet. The panels are pre-finished and the joints are pre-drilled, so it goes together in a clear sequence, but the tempered glass goes in last and needs careful two-person handling.

Does it need ventilation?
Yes. The Astra requires a 4.3" vent connected to a duct that runs outside the wall cavity, which carries warm, moist air away from the structure and protects it long-term. Choose a room where that duct run is possible - it's worth confirming before you order.

How much room do I actually need?
More than the cabin footprint. Plan for a minimum assembly clearance of 110" x 110" x 107" tall, a room ceiling height of at least 8', and a required 2" air gap between the unfinished cabin sides and adjacent walls.

What electrical setup does it need?
The 9kW Harvia Virta heater needs a dedicated 240V, 40-amp circuit; the lighting runs on 110V. All electrical work - heater, controller, and LED wiring - must be completed by a licensed electrician, and is done during assembly.

Does it need a special floor?
It sits directly on existing level, water-resistant flooring - concrete, ceramic tile, vinyl, or laminate. If your floor doesn't qualify, an alternative base may be needed.

Can I control it from my phone?
Yes - the Harvia Xenio control offers a 12-hour delay start, weekly scheduling, and Wi-Fi control through the MyHarvia app, so it's hot when you want it.

What's included?
Sauna stones, the control and temperature sensor, two headrests, a wood platform, and MyHarvia app access. Optional accessories (pail and ladle, cushions, aromatherapy, decorative stones) are available.

Can I move it later?
Yes - it can be disassembled and relocated. Because of the glued ceiling frame, the glass handling, and the vent connection, treat a move as a planned reinstall rather than a quick shuffle.